On Wed, 13 Jan 2010, Jeffrey Altman wrote:
On 1/13/2010 3:20 PM, Buhrmaster, Gary wrote:
For the time being at least, set the RxMaxMTU value back to 1260 octets.
This will result in a performance penalty but will avoid this data
corruption. Hopefully one night soon I will wake up in the middle of
the night understanding where and how this data corruption is taking place.
You mention SEP 11.0.4. Does the problem still exist in release update 5?
Richard said in his e-mail that the problem could not be recreated with
11.0.5.
To followup with respect to SEP 11.0.5, we have never seen file
corruption, but we have seen temporary network lockup ( a known issue with
older SEP versions too) and general performance degradation with some
combinations of parameters.
Interface-MTU RxMaxMTU Client-threads Network-bandwith-utilization
not set 0 4 25-45%, no lockups (default settings)
not set 0 4 30-50%, no lockup, exempt AFScache
from SEP scanning
1300 0 4 0-50%, network lockups
1300 0 1 0-50%, network lockups
1300 1260 1 25-40%, no lockups
This is based on tests with just two machines, so should not be taken as
definitive, but it seems that SEP 11.0.5 does not cause problems on a
machine with the default MTU configuration.
I ask because of the following "interesting" fixes in RU5:
http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2007121216360648
With NICs that use a TCP offload engine, Symantec Endpoint Protection with
Network Threat Protection enabled causes networking problems, such as
connection failures and performance degradation
Fix ID: 1389258
Symptom: Teefer2 causes packet loss with TCP/UDP checksum offload by not
preserving checksum data.
Solution: Teefer2 corrected to preserve checksum data.
DNS resolution fails while connected via Microsoft VPN
Fix ID: 1442277
Symptom: Teefer2 causes packet loss with TCP/UDP checksum offload by not
preserving checksum data.
Solution: Teefer2 corrected to preserve checksum data.
--
Richard Brittain, Research Computing Group,
Kiewit Computing Services, 6224 Baker/Berry Library
Dartmouth College, Hanover NH 03755
[email protected] 6-2085
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