TNPFA 4.1.1 Installation and User Guide - e IBM Tivoli Composite ...

The memory footprint for each TVA is dependent on how many buckets it has to hold.
Period Coverage Number of
Buckets
Resolution
(seconds)
Resolution TVA Memory
Requirement
Hour 1 hour 360 10 10 seconds 12296 Bytes
Day 25 hours 300 300 5 minutes 10376 Bytes
Week 7 days 1 hour 338 1800 30 minutes 11592 Bytes
Month 31 days 2 373 7200 2 hours 12712 Bytes
hours
Quarter 93 days
4 hours
26 minutes
40 seconds
272 29600 8 hours
13 minutes
20 seconds
9480 Bytes
Year 366 days 366 86400 24 hours 12488 Bytes
Month 31 days 8940 300 5 minutes 286856 Bytes.
(HiRes) 1 hour
Figure 3-7 Memory requirements
The number of TVAs that must be stored depends on the traffic that is received. If all the flows are for
one IP Address, Application Name pair then there is one TVA. If only a single octet is sent to another
port on that same IP address then a second TVA is created for that IP Address, Application Name pair
to hold that information. The memory footprint is the same for any aspect that records octets, flows, or
packets.
As traffic information is analyzed by Tivoli Netcool Performance Flow Analyzer, the number of TVAs
increases as the flow analyzer recognises that existing TVAs do not cover the data presented. If the
traffic is quite widely spread across IP address and ports, the memory required to store all the octets
broken down by IP Address, Application Name increases by TVA, until the available RAM is used up
by Tivoli Netcool Performance Flow Analyzer. To avoid RAM being consumed without restrictions,
there are two attributes of each aspect- Upper Limit and Maximal Number. By default, these values are
4000 and 2000 respectively.
If the number of TVAs grows to reach the value of Upper Limit, TVAs are deleted to bring the number
of TVAs down to the Maximal Number. The TVAs that are removed are deleted, and their data is lost.
The total amounts are still maintained. No guarantee is made regarding which TVAs are removed, but
an effort is made to keep the same distribution of TVAs based on amount of traffic.
For the data for one hour of octets, 4000 separate IP Address and Application Name combinations, the
amount of RAM required is 4000 * 12,296 Bytes = 49,184,000 Bytes or 46.9 MB.
If we were to record an hour, day, week, month, quarter, and year of octets, packets, and flows for
Host Application that hit 4000 TVAs, then the calculation would be:
(12,296 + 10,376 + 11,592 + 12,712 + 9,480 + 12,488) * 3 units * 4,000 TVAs = 68,944 * 3 * 4,000 =
827,328,000 Bytes or 789 MB.
The same default values for Upper Limit and Maximal Number operate for each aspect type even though
certain aspects could not reach 4000 TVAs. For example, there are likely to be only a certain number of
flow emitters in a network.
© Copyright IBM Corp. 2004, 2010 23