Endace Measurement Systems Limited
http://www.endace.com
EDM01.05-12r1 DAG 3.7T Card User Manual
Copyright, all rights reserved.
28
Version 6. 22 September 2005.
4.2 High Load Performance
, continued
Increasing
buffer size
The host PC buffer can be increased to deal with bursts of high traffic load
on the network link.
By default the dagmem driver reserves 32MB of memory per DAG card in
the system. Capture at OC-12/STM-4 (622Mbps) rates and above may
require a larger buffer.
128MB or more is suggested for Linux/FreeBSD.
For the DAG 3.7T card Windows operating system the upper limit is
32MB.
In Debian Linux the amount of memory reserved is changed by editing
file
/etc/modules
:
# For DAG 3.x, default 32MB/card
dagmem
#
# For DAG 4.x or 6.x, use more memory per card, E.G.
# dagmem dsize=128m
The option
dsize
sets the amount of memory used per DAG card in the
system.
The value of
dsize
multiplied by the number of DAG cards must be less
than the amount of physical memory installed, and less than 890MB.
