Tweaking The Statistics Memory Configuration - Network Instruments GigaStor User Manual

Tweaking the statistics memory configuration

There are two kinds of buffers that a probe instance uses to store data in real-time: a capture buffer and a
statistical buffer. The capture buffer stores raw data captured from the network; the statistical buffer stores
statistical entries and nothing more. This section is only concerned with statistical buffers.
The default statistics configuration is sufficient for most users and does not need to be changed. The memory
settings are preconfigured based on network size and network type. Choose the type of network you are
monitoring with this probe instance.
Each statistic is collected in its own section of RAM, where the processed data is stored. Alias List Entries is the
first entry. It is used in the Discover Network Names portion of Observer. It has 800 allocated entries (stations),
which consumes 114.4 kilobytes of RAM. When Discover Network Names is running, the captured packet is
passed to the statistics queue buffer. After the data is processed, it is passed to the statistical memory buffer and
to each relevant Observer statistic for that particular network type.
Observer collects statistics for numerous types of applications and trending, some of which may not apply to
your network. You may increase or decrease the allocated entries as necessary.
For instance, if you are using Discover Network Names it will run until it fills the 800 stations. After it reaches 800
entries it cannot add any more because there is no memory space available. Any stations beyond 800 are not
included in the list. You must increase the number of stations that may be allocated. This increases the memory
requirements though. If you have 8,500 stations on your network, you will need at least 8,500 entries, which
requires 1.2 MB of RAM.
Conversely, if you are not using statistics, such as VoIP, the RAM is still allocated to it. The default VoIP Trending
is for 1,500 entries, which requires 12.6 MB of RAM. By reducing the allocated entries to 10 (the minimum) you
need only 86.3 KB of RAM — saving nearly 12 MB to be used elsewhere.
By tweaking the statistics allocation, you can fine tune how Observer processes its data.
You cannot modify the default statistics memory configuration. You must create a new profile based on one of
the existing profiles (Small, Medium, Large, 4G LTE) and modify it.
1. Click the Memory Management tab to display the list of probe instances and their buffer sizes.
2. Select a probe instance and click Configure Memory to change the packet capture or statistics queue buffer
sizes. The Edit Probe Instance window opens.
3. Click the New button to open the New Statistics Memory Configuration window.
4. Type a name and choose which memory configuration on which you want to model yours. Click Finish. You
have now created a new statistics configuration, but it is identical to the one you modeled yours on. You
must now edit it.
5. Click Edit. Click Yes to the message that appears about needing to restart the probe software after making
memory changes. The Edit Statistics Memory Configuration appears.
6. At the top, choose your network type from the list.
7. The statistic's memory that you can modify are highlighted in yellow. To change the amount of memory for
it, click in the Allocated Entries column and provide a new value. Repeat until you have tweaked the statistics
memory for your needs.
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