Addional Disk Space for JTI Analycs in ElascSearch
Considerable storage space is needed to support JTI analycs in ElascSearch. Each JTI record event
requires approximately 330 bytes of disk space. A reasonable esmate of the number of events
generated is (<num-of-interfaces> + <number-of-LSPs>) ÷ reporng-interval-in-seconds = events per
second.
So for a network with 500 routers, 50K interfaces, and 60K LSPs, with a congured ve-minute
reporng interval (300 seconds), you can expect something in the neighborhood of 366 events per
second to be generated. At 330 bytes per event, it comes out to 366 events x 330 bytes x 86,400
seconds in a day = over 10G of disk space per day or 3.65T per year. For the same size network, but
with a one-minute reporng interval (60 seconds), you would have a much larger disk space requirement
—over 50G per day or 18T per year.
There is an addional roll-up event created per hour per element for data aggregaon. In a network with
50K interfaces and 60K LSPs (total of 110K elements), you would have 110K roll-up events per hour. In
terms of disk space, that would be 110K events per hour x 330 bytes per event x 24 hours per day =
almost 1G of disk space required per day.
For a typical network of about 100K elements (interfaces + LSPs), we recommend that you allow for an
addional 11G of disk space per day if you have a ve-minute reporng interval, or 51G per day if you
have a one-minute reporng interval.
See NorthStar Analycs Raw and Aggregated Data Retenon in the
NorthStar Controller User Guide
for
informaon about customizing data aggregaon and retenon parameters to reduce the amount of disk
space required by ElascSearch.
Addional Disk Space for Network Events in Cassandra
The Cassandra database is another component that requires addional disk space for storage of
network events.
Using that same example of 50K interfaces and 60K LSPs (110 elements) and esmang one event
every 15 minutes (900 seconds) per element, there would be 122 events per second. The storage
needed would then be 122 events per second x 300 bytes per event x 86,400 seconds per day = about
3.2 G per day, or 1.2T per year.
Using one event every 5 minutes per element as an esmate instead of every 15 minutes, the addional
storage requirement is more like 9.6G per day or 3.6T per year.
For a typical network of about 100K elements (interfaces + LSPs), we recommend that you allow for an
addional 3-10G of disk space per day, depending on the rate of event generaon in your network.
By default, NorthStar keeps event history for 35 days. To customize the number of days event data is
retained:
10