Network Instruments GigaStor 114ff - Manual (Page 113)

What is a probe instance?
Chapter 8 Probe Instances
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instances to the Gen2 adapter if at all possible. A copy of all
packets are sent from the adapter to every passive probe
instance attached to it. If you have several passive probe
instances attached to the Gen2 adapter, the Gen2’s
performance is significantly affected. Instead attach the
passive probe instances to either a 10/100/1000 adapter or to
a non-existent one.
If you have a passive probe instance connected to a GigaStor, it can
mine data that has already been written to the RAID disk by an active
probe instance. There should be one passive probe instance for each
simultaneous Observer user on a GigaStor. By using a passive probe
instance instead of an active probe instance only one copy of data is
being captured an written to disk, which reduces the processor load
and the required storage space. For troubleshooting and most uses in
Observer passive probe instances are appropriate.
By default a passive probe instance uses 12 MB of RAM. You can
reserve more memory for passive probe instances if you wish.
An active probe instance on a GigaStor captures network traffic and
writes it to the RAID array. A active probe instance should have as
large of a RAM buffer as possible to cushion between the network
throughput rate and the array write rate.
Like a passive probe instance, it can also be used to mine data from
the hard disk, however a passive instance is better suited for the task.
An active probe instance cannot start a packet capture while the
GigaStor Control Panel is running.
T IP ! A CTIVE PROBE
INSTANCE BEST
PRACTICES
Q
Only one active probe instance per GigaStor.
Q
Set scheduling to Always for the active probe instance so that
it is constantly capturing and writing data. Use a passive
probe instance to mine the data.
Q
Do not pre-filter, unless you know exactly what you want to
capture. Of course, if something occurs outside the bounds of
the filter, you will not have the data in the GigaStor.
Q
Do not allow remote users access to the active probe instance.