HP StorageWorks XP128 User manual

Brand: HP

Model: StorageWorks XP128

Type: User manual

This manual is also suitable for

HP StorageWorks

Cache LUN XP user guide

for the XP10000/XP12000

Part number: T1716-96002

Second edition: December 2005

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Cache LUN XP user guide for the XP10000/XP12000

Cache LUN XP user guide for the XP10000/XP12000 3

About this guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Intended audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Prerequisites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Firmware versions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Related documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Document conventions and symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

HP technical support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Subscription service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Helpful web sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1 Cache LUN XP for the XP10000/XP12000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Supported volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Cache LUN XP tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Supported emulation types and other parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Supported emulation types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Modified volume types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Unit of cache area allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Number of cache areas allowed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Restrictions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Cache LUN XP modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Priority mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Priority mode details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

General cache capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Bind mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Bind mode details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Bind mode and RAID groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Pre-staging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Required cache size for Cache LUN XP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Open systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Mainframe systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Starting Cache LUN XP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Cache LUN pane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

CLPR drop-down list. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Prestaging check box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

LDEV tree. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

LDEV table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Cache LUN XP pie chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Cache settings section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Setting (creating) a cache extent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Releasing (removing) a cache extent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Changing an extent’s mode and pre-staging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Partial Cache Residence (PCR) operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Overview of the PCR function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

PCR operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

PCR pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Viewing the current PCR settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Setting the PCR cache for management information (i-node) and log information . . . . . . . . . . . . . . . . . 24

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Figures

1 Cache LUN XP operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Example of LBA value setting with LUSE volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Contents

3 Cache LUN pane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4 Multi Set pane. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

5 Multi Release window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

6 PCR cache area (cache extent) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

7 PCR pane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

8 PCR information table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Tables

1 Recommended and minimum firmware versions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 Document conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3 Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4 Cache LUN XP icons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Cache LUN XP user guide for the XP10000/XP12000 5

About this guide

This guide provides information about the following:

• ”Supported volumes” on page 9

• ”Cache LUN XP tasks” on page 9

• ”Supported emulation types and other parameters” on page 9

• ”Restrictions” on page 10

• ”Cache LUN XP modes” on page 11

• ”Pre-staging” on page 12

• ”Required cache size for Cache LUN XP” on page 13

• ”Starting Cache LUN XP” on page 16

• ”Setting (creating) a cache extent” on page 18

• ”Partial Cache Residence (PCR) operations” on page 22

Intended audience

This guide is intended for customers and HP-authorized service providers with knowledge of the following:

• Disk array hardware and software

• Data processing and RAID storage subsystems and their basic functions

Prerequisites

Prerequisites for using this product include:

• Installation of the HP StorageWorks disk array(s)

• Installation of the license key for this product

Firmware versions

The recommended firmware versions shown below provide the optimal level of support for the features

provided with this product. Older firmware versions can be used; however, product features enabled with

newer firmware will not appear.

Table 1 Recommended and minimum firmware versions

Related documentation

In addition to this guide, please refer to other documents for this product:

• HP StorageWorks Command View XP User Guide for XP Disk Arrays

• HP StorageWorks XP Remote Web Console User Guide for XP12000/XP10000

•

HP StorageWorks Snapshot XP User Guide

You can find these documents at http://www.hp.com/support/rwc/manuals

XP disk array Minimum Recommended

XP12000 50-04-31-00/00 50-04-41-00/00 or later

XP10000 50-04-31-00/00 50-04-41-00/00 or later

Document conventions and symbols

CAUTION: Indicates that failure to follow directions could result in damage to equipment or data.

IMPORTANT: Provides clarifying information or specific instructions.

NOTE: Provides additional information.

TIP: Provides helpful hints and shortcuts.

HP technical support

Telephone numbers for worldwide technical support are listed on the HP support web site:

http://www.hp.com/support/

Collect the following information before calling:

• Technical support registration number (if applicable)

• Product serial numbers

• Product model names and numbers

• Applicable error messages

• Operating system type and revision level

• Detailed, specific questions

For continuous quality improvement, calls may be recorded or monitored.

Table 2 Document conventions

Convention Element

Blue text: Table 1

Cross-reference links and e-mail addresses

Blue, underlined text:

(http://www.hp.com)

Web site addresses

Bold text

• Keys that are pressed

• Text typed into a GUI element, such as a box

• GUI elements that are clicked or selected, such as menu and list

items, buttons, and check boxes

Italic text

Text emphasis

Monospace text

• File and directory names

• System output

• Code

• Commands, their arguments, and argument values

Monospace, italic text

• Code variables

• Command variables

Monospace, bold text

Emphasized monospace text

Cache LUN XP user guide for the XP10000/XP12000 7

Subscription service

HP strongly recommends that customers register online using the Subscriber's choice web site:

http://www.hp.com/go/e-updates

Subscribing to this service provides you with e-mail updates on the latest product enhancements, newest

driver versions, and firmware documentation updates as well as instant access to numerous other product

resources.

After subscribing, locate your products by selecting Business support and then Storage under Product

Category.

Helpful web sites

For additional information, see the following HP web sites:

• h

ttp://www.hp.com

• http://www.hp.com/go/storage

• http://www.hp.com/support

• http://www.hp.com/support/rwc/manuals

Cache LUN XP user guide for the XP10000/XP12000 9

1 Cache LUN XP for the XP10000/XP12000

Use HP StorageWorks Cache LUN XP to reserve areas of cache memory on the disk array for storing

high-use data from the LDEVs. Data access speed is improved because the cache-resident data is available

to the hosts at much faster transfer speeds. This can be applied to both read and write I/O operations.

Supported volumes

Cache LUN XP works with normal volumes, LUSE volumes, and custom volumes (configured through VSC).

Use custom volumes and Cache LUN XP together to achieve higher data access performance (than when

these features are used separately).

Cache LUN XP tasks

Use Cache LUN XP to perform the following tasks:

• ”Setting (creating) a cache extent” on page 18

• ”Releasing (removing) a cache extent” on page 20

• ”Changing an extent’s mode and pre-staging” on page 21

Figure 1 Cache LUN XP operations

Cache LUN XP requires a portion of cache memory, called the Cache LUN XP cache area. You can

change the capacity of the Cache LUN XP cache area when installing or removing cache memory.

Typically, data assigned to Cache LUN XP becomes resident (staged) in cache after it is first accessed by a

host. Then, the host finds the data in cache for the second and subsequent accesses.

Another function, called pre-staging, puts data in the Cache LUN XP cache area when the data is first set

up for caching. Pre-staging allows the host to find data in the cache at the first access.

Cache areas (also called cache extents) can be added or removed at any time. Each cache extent is

defined as a range of logical blocks within an LDEV or as an entire LDEV. Logical blocks are defined by

starting and ending Logical Block Addresses (LBAs).

Supported emulation types and other parameters

Supported emulation types

Supported open system emulation types are OPEN-3, OPEN-8, OPEN-9, OPEN-E, OPEN-L, and OPEN-V.

Supported mainframe emulation types are 3390-3, 3390-3A, 3390-3B, 3390-3C, 3390-3R, 3390-9,

3390-9A, 3390-9B, 3390-9C, 3390-L, 3390-LA, 3390-LB, 3390-LC, 3390-M, 3390-MA, 3390-MB, and

3390-MC.

Modified volume types

LUSE (LU Size Expansion) and VSC (Volume Size Configuration) volumes can be placed in the Cache LUN

XP cache area.

If you want to apply Cache LUN XP to a LUSE volume, you must apply Cache LUN XP to all the LDEVs that

form the LUSE volume.

10 Cache LUN XP for the XP10000/XP12000

Unit of cache area allocation

A Cache LUN XP extent is a range of logical blocks within an LDEV. A logical block is 512 bytes.

For OPEN-V, a cache extent must have at least 128 Logical Block Addresses (LBAs), or 66 KB. For all other

supported open system emulation types, a cache extent must have at least 96 LBAs, or 49.5 KB. This is

known as a cache slot. A cache extent can have a maximum size of an entire LDEV, up to the limits of

Cache LUN XP cache memory. Allocate data to Cache LUN XP with a minimum size of 128 LBAs for

OPEN-V and 96 LBAs for other than OPEN-V.

For mainframe systems, a cache extent must be at least one cache slot or track (48 KB or 64 KB). Its

maximum size may be an entire LDEV, up to the limits of Cache LUN XP cache memory. Allocate data to

Cache LUN XP in units of cylinders and tracks.

Number of cache areas allowed

• In DKC: 1,024

• In LDEV: 1,024

Restrictions

Table 3 Restrictions

Configuration Restrictions • Do not exceed the capacity of the Cache LUN XP cache.

• Do not configure an Auto LUN reserved volume for Cache LUN XP.

• Do not place an LDEV in cache twice.

• You cannot allocate Cache LUN XP cache space for an on-demand LDEV.

• If you allocate Cache LUN XP on the Volume Management Area (VMA) volume

for LUN Security XP Extension, set 10,240 LBAs (5 MB or larger) for the

starting logical block address of the user data. To do this, add 10,240 LBAs to

the LBA value recognized on the host side.

• To apply Cache LUN XP to a LUSE volume using Select All Area, you must

apply it to all the LDEVs that form the LUSE volume.

• If you want to set Cache LUN XP for an LDEV within a LUSE volume using LBAs,

you must know the exact number of LBAs in each LDEV in the LUSE volume.

The number of LBAs listed in the Cache LUN XP panel is only for a single LDEV

and does not match the number of LBAs recognized by the host if the mounted

volume is a LUSE volume.

To identify the exact number of LBAs in an LDEV, display the Basic Information

Display pane, and determine the parity group to which the LDEV belongs.

Next, display the Customized Volume panel and find the exact number of LBAs

in the LDEV.

NOTE: For more information about the Basic Information Display pane,

refer to the HP StorageWorks XP Remote Web Console user guide.

For more information about customized volumes, refer to the HP

StorageWorks LUN Configuration and Security Manager XP user guide.

Cache LUN XP user guide for the XP10000/XP12000 11

Cache LUN XP modes

Cache LUN XP has two modes:

• priority mode

• bind mode

Priority mode

Priority mode requires fewer cache resources but has performance limitations over bind mode. Priority

mode keeps all read data in cache (until you delete the extent), but all writes are destaged to disk normally

(using the same algorithms as for regular, non-Cache LUN XP data). You can set the priority mode from the

operations box located on the lower-right of the Cache LUN pane.

Priority mode details

• All reads following the initial read to a block will result in cache hits (100% cache read hits).

• After destaging of the write block to disk, the duplicated write areas in general cache become free.

• While destaging to disk, read requests to the same block are delayed until the disk operation is

completed.

• Priority mode generates write traffic to disk, whereas bind mode does not.

Configuration Restrictions For example, in Figure 2, the LUSE volume is composed of three LDEVs (00:01,

1,000 LBAs, 00:02, 1,002 LBAs, and 00:03, 1,020 LBAs). If you want to set

Cache LUN XP to 500 LBAs starting from LBA number 1,020, you can set

Cache LUN XP to 500 LBAs starting from LBA number 20 on the second LDEV,

because the first LDEV size is 1,000 LBAs.

Figure 2 Example of LBA value setting with LUSE volumes

• You cannot allocate Pool-VOLs and V-VOLs for Cache LUN XP. For more

information, see the HP StorageWorks Snapshot XP User Guide.

Usage Restrictions • If an LDEV is placed in cache, do not use it for BC/Continuous Access XP quick

restore operations or Auto LUN migration. These operations may swap the

internal locations of the primary and secondary volumes and cause a loss of

data integrity.

• You cannot change a Cache LUN XP extent after it is configured. To change the

specification, you must reset (release) the Cache LUN XP extent, and then

re-allocate (

set) the Cache LUN XP extent.

VSC Automatic Resets In the following cases, a Cache LUN XP cache extent is deleted (reset or released)

automatically:

• If a fixed volume, part or all of which is assigned to Cache LUN XP, is

converted into free space by the VSC Volume to Space function.

• If a custom volume, part or all of which is assigned to Cache LUN XP, is

converted into free space using the VSC Volume to Space function.

• If an LDEV (or VDEV) containing fixed and custom volumes assigned to Cache

LUN XP is initialized by the VSC Volume Initialize function.

Table 3 Restrictions (continued)

12 Cache LUN XP for the XP10000/XP12000

General cache capacity

In addition to the Cache LUN XP cache, you should set the general cache capacity according to the

number of areas set in priority mode. This prevents a reduction in general cache performance.

If the general cache is overloaded (having very little cache space), this can result in a wait for free cache

space. This may degrade access to the general cache.

• If you set up to 512 areas in Cache LUN XP, set 512 MB x 2 (1024 MB) of standard cache.

• If you set 513-1024 areas in Cache LUN XP, set 1024 MB x 2 (2048 MB) of standard cache.

• For OPEN-V, one slot is 66 KB, which requires 4 cache segments (16.5 KB/segment). For example,

16 slots require 1,056 KB of reserved cache.

• For other than OPEN-V, one slot is 49.5 KB, which requires 3 cache segments. For example, 16 slots

require 792 KB of reserved cache.

Bind mode

Bind mode keeps both read and write data in cache, eliminating disk traffic (100% read/write hits). All

data stays in cache until the extent is removed. The data stored in the Cache LUN XP cache is duplexed for

data protection, which requires additional Cache LUN XP cache capacity. If AC power is lost, data is

maintained in cache for up to 48 hours, using battery power. You can set the bind mode from the

operations box located on the lower-right of the Cache LUN pane.

Bind mode details

• All reads following the initial read to a block will result in cache hits.

• Duplicated write blocks are stored in cache and are never “evicted.”

• All read or write blocks stay resident in cache until the extent is deleted.

• Bind mode requires more cache because duplicated write blocks are not destaged to disk.

Bind mode and RAID groups

For RAID-5 or RAID-6 parity groups, a Cache LUN XP extent in bind mode requires a cache capacity three

times larger than the user data.

• For OPEN-V, one slot is 66 KB, which requires 12 cache segments (16.5 KB/segment). For example,

16 slots require 3,168 KB of reserved cache.

• For other than OPEN-V, one slot is 49.5 KB, which requires 9 cache segments. For example, 16 slots

require 2,376 KB of reserved cache.

For RAID-1 parity groups, a Cache LUN XP extent in bind mode requires a cache capacity twice as large

as user data.

• For OPEN-V, one slot is 66 KB, which requires 8 cache segments (16.5 KB/segment). For example,

16 slots require 2,112 KB of reserved cache.

• For other than OPEN-V, one slot is 49.5 KB, which requires 6 cache segments. For example, 16 slots

require 1,584 KB of reserved cache.

To change a RAID-1, RAID-5, or Raid-6 parity group’s mode from priority mode to bind mode, reset and

re-allocate the affected Cache LUN XP extent. When you re-allocate, specify the greater capacity needed

for bind mode.

Pre-staging

As mentioned before, data assigned to a Cache LUN XP cache extent becomes resident (“staged”) in

cache after it is first accessed by the host. Then, the host finds the data in cache for the second and

subsequent accesses. The pre-staging function puts data in cache before the first read. Therefore,

pre-staging allows the host to find data in cache on the first access.

Specify pre-staging when you set up the cache extent. You can use this function with either priority or bind

mode.

You cannot change a Cache LUN XP extent after it is configured. To change the specification, you must

reset (“release”) the Cache LUN XP extent, and then re-allocate (“set”) the Cache LUN XP extent.

Cache LUN XP user guide for the XP10000/XP12000 13

Required cache size for Cache LUN XP

The required cache size for Cache LUN XP depends on the operation modes. For example, in bind mode,

RAID-1 groups require twice the cache size for user data to use Cache LUN XP. However, RAID-5 or RAID-6

groups require three times the cache size for user data to use Cache LUN XP.

NOTE: When external volumes are used, twice the cache size is required for user data to use Cache

LUN XP.

In priority or bind mode, cache size is calculated with the assumption that one slot is the following:

• Open-system volumes

For OPEN-V, one slot is 264 KB (512 LBAs)

For other than OPEN-V, one slot is 66 KB (128 LBAs)

• zSeries and S/390 (3390) volumes

One slot is 66 KB (128 LBAs)

The following sections describe the calculation procedures for each operation mode and RAID level.

Open systems

To calculate the cache size for open systems:

1. Calculate the converted values of the starting and ending addresses.

For specified LDEVs:

a. OPEN-V

Number of LBAs = LDEV size (KB) × 2

Convert LDEV size to number of LBAs

Number of slots = (↑Number of LBAs ÷ 512↑)

Round up the calculated value between the two up arrows (↑) after the decimal point

Converted value of starting address = 0

Converted value of ending address = (Number of slots × 512) - 1

b. Emulation types other than OPEN-V

Number of LBAs = LDEV size (KB) × 2

Convert LDEV size to number of LBAs

Number of slots = (↑Number of LBAs ÷ 96↑)

Round up the calculated value between the two up arrows (↑) after the decimal point

Converted value of starting address = 0

Converted value of ending address = (number of slots × 96) - 1

14 Cache LUN XP for the XP10000/XP12000

For specified volumes:

a. OPEN-V

Starting value = (↓Setting value of starting address (LBA) ÷ 512↓)

Round down the calculated value between the two down arrows (↓) after the decimal point

Setting value of starting address (LBA) is the value entered in the operations box on the Cache

LUN pane

Ending value = (↓Setting value of ending address (LBA) ÷ 512↓)

Round down the calculated value between the two down arrows (↓) after the decimal point

Setting value of ending address (LBA) is the value entered in the operations box on the Cache

LUN pane

Converted value of starting address = Starting value × 512

Converted value of ending address = ( (Ending value +1) × 512) - 1

b. Emulation types other than OPEN-V

Starting value = (↓Setting value of starting address (LBA) ÷ 96↓)

Round down the calculated value between the two down arrows (↓) after the decimal point

Setting value of starting address (LBA) is the value entered in the operations box on the Cache

LUN pane

Converted value of starting address = Starting value × 96

Converted value of ending address = ( (Ending value +1) × 96) - 1

2. Calculate the number of addresses between the starting and ending addresses calculated in step 1.

a. OPEN-V

Number of address = Converted value of ending address - Converted value of starting address + 1

Calculate the number of LBAs used by the user data

b. Emulation types other than OPEN-V

Number of LBAs = Converted value of ending address - Converted value of starting address + 1

Calculate the number of LBAs used by the user data

Number of slots = Number of LBAs ÷ 96

Convert the number of LBAs to the number of slots

Number of addresses = Number of slots × 128

Convert the number of slots with 128 LBA

3. Calculate the required cache size according to the operation modes, or RAID levels, to use Cache

LUN XP.

a. Bind mode

RAID-1:

Required cache size = Number of addresses × (512 ÷ 16) × 2 ÷ 1,024

Units are KB

RAID types other than RAID-1:

Required cache size = Number of addresses × (512 ÷ 16) × 3 ÷ 1,024

Units are KB

b. Priority mode

Required cache size = Number of addresses × (512

÷ 16) ÷ 1,024

Units are KB

Cache LUN XP user guide for the XP10000/XP12000 15

NOTE: If a RAID-5 or RAID-6 volume area is changed from priority mode to bind mode and no cache is

added, only 33 percent of the user data fits into the area previously assigned for priority mode. The

remaining 67 percent is used to save read/write data. If a RAID-1 volume area is changed from priority

mode to bind mode and no cache is added, only 50 percent of the user data fits in the area previously

assigned for priority mode. The remaining 50 percent is used to save read/write data. Changing the

mode without cache extension requires Cache LUN XP reconfiguration.

Mainframe systems

To calculate the cache size for mainframe systems:

1. Calculate the converted values of the starting and ending addresses.

For specified LDEVs:

Setting value of ending address (CC) = (↓((LDEV size × 15) - 1) ÷ 15↓)

Round down the calculated value between the two down arrows (↓) after the decimal point

Setting value of ending address (CC) is the value that is input to the operations box in the Cache

LUN pane)

Setting value of ending address (HH) = ( (LDEV size × 15) - 1) Mod15

Remainder is the setting value of ending address (HH)

Setting value of ending address (HH) is the value entered in the operations box on the Cache

LUN pane

Converted value of starting address = 0

Converted value of ending address = Setting value of ending address (CC) × 15 + Setting value of

ending address (HH)

Setting value of ending address (CC) and Setting value of ending address (HH) are the values

entered in the operations box on the Cache LUN pane

For specified volumes:

Converted value of starting address = Setting value of starting address (CC) × 15 + Setting value of

starting address (HH)

Setting value of ending address (CC) and Setting value of ending address (HH) are the values

entered in the operations box on the Cache LUN pane

Converted value of ending address = Setting value of ending address (CC) × 15 + Setting value of

ending address (HH)

Setting value of ending address (CC) and Setting value of ending address (HH) are the values

entered in the operations box on the Cache LUN pane

2. Calculate the number of addresses between the starting and ending addresses calculated in step 1.

Number of addresses = Converted value of ending address - Converted value of starting

address +1

Calculate the number of addresses of cache used by the user data

3. Calculate the required cache size according to the operation modes, or RAID levels, to use Cache

LUN XP.

a. Bind mode

RAID-1:

Required cache size = (Number of addresses × ( (128 × (512 + 16) ) × 2) ÷ 1,024

Units are KB

RAID types other than RAID-1:

Required cache size = (Number of addresses × (128 × (512 + 16) ) × 3) ÷ 1,024

Units are KB

16 Cache LUN XP for the XP10000/XP12000

b. Priority mode

Required cache size = (Number of addresses × (128 × (512 + 16) ) ) ÷ 1,024

Units are KB

NOTE: If a RAID-5 or RAID-6 volume area is changed from priority mode to bind mode and no cache is

added, only 33 percent of the user data fits into the area previously assigned for priority mode. The

remaining 67 percent is used to save read/write data. If a RAID-1 volume area is changed from priority

mode to bind mode and no cache is added, only 50 percent of the user data fits in the area previously

assigned for priority mode. The remaining 50 percent is used to save read/write data. Changing the

mode without cache extension requires Cache LUN XP reconfiguration.

Starting Cache LUN XP

1. Click Cache LUN in the left pane. The Cache LUN pane appears.

Figure 3 Cache LUN pane

Cache LUN pane

This pane lists the following items.

CLPR drop-down list

Use this drop-down list to select a cache logical partition (CLPR). The CLPR drop-down list displays the CLPR

number and CLPR name.

When you select a CLPR, volumes belonging to the selected CLPR and cache information appear in the

LDEV tree.

NOTE: If you administer only one CLPR, the CLPR drop-down list is not available.

Prestaging check box

Select or clear this check box to enable or disable the pre-staging function:

• If you select this check box, set the Prestaging Mode to Yes and click Apply. A non-pre-staging

operation will be performed and then a pre-staging operation will be performed.

Cache LUN XP user guide for the XP10000/XP12000 17

• If you clear this check box and then click Apply, a non-pre-staging operation will be performed, but a

pre-staging operation will not be performed. If you select this check box later and then click Apply, only

a pre-staging operation will be performed.

When a pre-staging operation is in progress, the text Prestaging operation in progress is shown at the

bottom of the Cache LUN pane. The progress is displayed in percentage.

The Prestaging check box is enabled in Modify mode and is selected by default. However, the Prestaging

check box is disabled in either of the following conditions:

• No cache

• Prestaging mode is set to No for each cache

LDEV tree

The LDEV tree displays the CU number (for example, CU 00) and LDEV number (for example, LDEV 00)

available for Cache LUN XP operations in a tree. The tree uses the following icons to show the settings:

The LDEV tree does not show Auto LUN-reserved volumes because they cannot be used in Cache LUN XP

operations.

LDEV table

Information about the LDEV selected in the tree appears on a single line in the upper-right portion of the

pane. It includes LDEV number, emulation type, capacity, RAID level, and VMA information.

The LDEV’s capacity is shown in MB for open systems, or cylinders and tracks for mainframe systems. The

table shows the cache settings for the LDEV selected in the tree and contains the following columns:

• LBA (open systems only): Displays the logical block starting and ending addresses.

• CC HH (mainframe systems only): Displays the cylinder and head starting and ending addresses.

• Capacity: Displays the capacity of the cache extent in megabytes for open systems. Displays the

capacity of the cache extent in cylinders and tracks for mainframe systems.

• Mode: Displays the mode of the cache extent. PRIO indicates priority mode, BIND indicates bind mode,

and - indicates that the LDEV is not assigned to the cache.

• Prestage: If this is blank, then pre-staging is not set. ON indicates that pre-staging is set.

Cache LUN XP pie chart

The text above the pie chart lists the used cache and the amount of free space left in cache. For the

XP10000/XP12000, it also lists the total Cache LUN XP area and size that can be created in the SLPR

(storage logical partition).

In the pie chart, pink indicates the amount of cache available, blue shows cache used, and yellow shows

the size of the specified cache extent.

Cache settings section

Sets the mode and area for data that will reside in the Cache LUN XP cache. Also displays the settings for

an existing cache extent. This area contains the following:

• Cache LUN Mode): Select the Cache LUN XP mode by clicking either Bind or Prio.

• Prestaging Mode: Select the Prestaging check box (located above the LDEV tree) to perform the

pre-staging operation, and then click Apply. Click Yes if pre-staging is enabled. Click No if pre-staging

is disabled.

Table 4 Cache LUN XP icons

Icon Description

Indicates an LDEV for which Cache LUN XP is not set.

Indicates an LDEV for which Cache LUN XP is set.

Indicates a LUSE volume (two or more LDEVs) for which Cache LUN XP is not set.

18 Cache LUN XP for the XP10000/XP12000

• Start: The starting address for data that will reside in the cache. This is expressed as a logical block

address for open systems and as a cylinder and head address for mainframe systems.

• End: The ending address for data that will reside in the cache. This is expressed as a logical block

address for open systems and as a cylinder and head address for mainframe systems.

NOTE: If you specify the VMA volume, and it has not been set for Cache LUN XP yet, the next LBA of

LBAs for the VMA appears in the Start box.

• Select All Area: If you select this check box, all data areas in the selected LDEV will be set to Cache

LUN XP cache.

This check box can be selected if no data areas in the selected LDEV are set to Cache LUN XP cache.

This check box cannot be selected and is grayed out if some data areas in the selected LDEV are set to

Cache LUN XP cache. If you select the Select All Area check box, nothing will be set to the starting

address and the ending address, and the Start and End fields remain empty.

• Available Cache LUN Size): Displays the size you can set. Bind displays the size you should set for bind

mode and Prio displays the size you should set for priority mode.

• Multi Set / Release: Selecting this check box and then clicking Set displays the Multi Set pane, which

you can use to make Cache LUN XP settings on more than one LDEV. Selecting this check box and then

clicking Release displays the Multi Release pane, which you can use to cancel Cache LUN XP settings

on more than one LDEV.

Data that will reside in the Cache LUN XP cache is specified by the starting address in the Start field

and the ending address in the End field. When the Select All Area check box is selected, all data areas

of the selected LDEVs will be set for the Cache LUN XP.

If you cancel the settings, all the settings specified for the LDEV will be canceled.

The Multi Set / Release check box does not select and cancel an individual Cache LUN XP data area

specified for the LDEV. You must use the Release button to cancel an individual Cache LUN XP data

area.

If you select the VMA volume from the LDEV tree in the Cache LUN XP panel, only volumes for which

VMA is set are displayed in the Multi Set /Release panel. If you select a non-VMA volume, only

volumes for which VMA has not been set are displayed in the Multi Set/Release panel.

Buttons

• Set: Creates a cache extent.

• Release: Deletes a cache extent.

• Apply: Applies the parameters to the disk array. You can then set or release other cache extents.

• Cancel: Cancels the operation.

Setting (creating) a cache extent

1. In the LDEV tree of the Cache LUN pane, click the CU:LDEV number of the LDEV you want to put in

cache.

The LDEV table displays Cache LUN XP information for the LDEV you selected.

2. Select an area to be made resident in the Cache LUN XP cache from one of those marked “-” in the

Mode column. The Set button is enabled. The From and To boxes display the selected area’s values.

3. Click Bind or Prio to indicate the mode.

4. Click Yes or No to indicate whether to set pre-staging.

5. Complete one of the following steps:

• To place all data on an LDEV into cache, go to step 6.

• To place specific data from an LDEV into cache, go to step 7.

• To place all data on multiple LDEVs into cache, go to step 8.

• To place specific data from multiple LDEVs into cache, go to step 9.

6. To place all data on an LDEV into cache:

a. Select the Select All Area check box.

Cache LUN XP user guide for the XP10000/XP12000 19

b. Clear the Multi Set / Release check box.

c. Click Set. A confirmation dialog box appears.

d. Click OK to continue. The new settings are shown in blue on the Cache LUN pane. To cancel

operations, click Cancel. Go to step 10.

7. To place specific data from an LDEV into cache:

a. If the Select All Area check box is grayed out, go to the next step. If the Select All Area check box is

activated, clear the Select All Area check box.

b. Enter the starting and ending addresses (LBAs or CC HHs) of the area to be made resident in the

cache.

For open systems, Cache LUN XP identifies a logical area in units of 128 blocks for OPEN-V, and

96 blocks for other than OPEN-V. For OPEN-V, if you have entered 1 as the starting logical block

address and a value less than 128 as the ending logical block address, Cache LUN XP

automatically changes the ending block address to 128. For other than OPEN-V, if you have

entered 1 as the starting logical block address and a value less than 96 as the ending logical block

address, Cache LUN XP automatically changes the ending block address to 96.

c. Clear the Multi Set / Release check box.

d. Click Set. A confirmation dialog box appears.

e. Click OK to continue. The new settings are shown in blue on the Cache LUN pane. To cancel

operations, click Cancel. Go to step 10.

8. To place all data on multiple LDEVs into cache:

a. Select the Select All Area check box.

b. Select the Multi Set / Release check box.

c. Click Set. A confirmation dialog box appears.

d. Click OK to continue. The Multi Set pane appears.

Figure 4 Multi Set pane

e. In the CU drop-down list, click the CU.

f. In the table, click more than one LDEV and then click Set. The Multi Set pane closes and the new

settings are shown in blue on the Cache LUN pane. To cancel operations, click Cancel. Go to

step 10.

9. To place specific data from multiple LDEVs into cache:

a. If the Select All Area check box is grayed out, go to the next step. If the Select All Area check box is

activated, clear the Select All Area check box.

b. Enter the starting and ending addresses (LBAs or CC HHs) of the area to be made resident in the

cache.

20 Cache LUN XP for the XP10000/XP12000

For open systems, Cache LUN XP identifies a logical area in units of 128 blocks for OPEN-V, and

96 blocks for other than OPEN-V. For OPEN-V, if you have entered 1 as the starting logical block

address and a value less than 128 as the ending logical block address, Cache LUN XP

automatically changes the ending block address to 128. For other than OPEN-V, if you have

entered 1 as the starting logical block address and a value less than 96 as the ending logical block

address, Cache LUN XP automatically changes the ending block address to 96.

c. Select the Multi Set / Release check box.

d. Click Set. A confirmation dialog box appears.

e. Click OK to continue. The Multi Set pane appears.

f. In the CU drop-down list, click the CU.

g. In the table, click more than one LDEV and then click Set. The Multi Set pane closes and the new

settings are shown in blue on the Cache LUN pane. To cancel operations, click Cancel. Go to

step 10.

10.To make data in other volumes reside in the Cache LUN XP cache, repeat the previous steps.

NOTE: You cannot use the Release button to delete the set data until you click Apply or Cancel.

11.To enable the pre-staging function, select the Prestaging check box. To disable the pre-staging function,

clear the Prestaging check box.

12.If the settings are correct, click Apply. A confirmation dialog box appears.

13.Click OK to confirm. The Cache LUN XP operation begins. If prestaging was selected, the prestaging

operation will occur next. When the operation has been completed, a confirmation dialog box

appears.

14.Click OK.

Releasing (removing) a cache extent

1. In the LDEV tree of the Cache LUN pane, click the CU:LDEV number of the LDEV you want to remove

from cache. The LDEV table displays Cache LUN XP information about the LDEV you selected.

2. Select an extent to be removed from the Cache LUN XP cache. The Release button is enabled.

3. Complete one of the following steps:

• To remove specific data from cache, go to step 4.

• To remove all data from cache, go to step 5.

4. To remove specific data from cache:

a. Click Release. A confirmation dialog box appears.

b. Click OK to continue. The new settings are shown in blue on the Cache LUN pane. To cancel

operations, click Cancel. Go to step 6.

5. To remove all data from cache

a. Select the Multi Set / Release check box.

b. Click Release. A confirmation dialog box appears.

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