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|Affected OS Type
|Affected Release Number
|WAAS - so_dre created a core file
Wide Area Application Services (WAAS) Version 5.1.1e has been pulled from Cisco.com due to a Data redundancy Elimination (DRE) defect which causes the DRE process to crash and core dump. The process restarts and continues to write a core which could cause the disc drive to fill. This means the WAAS device goes into bypass mode and traffic is no longer being optimized.
A severe defect with regards to DRE was found in WAAS version 5.1.1e. In the best interest of our customers, version 5.1.1e is not recommended for any deployments and has been removed from the software library on Cisco.com.
These scenarios could cause the DRE problem to manifest:
-Sometimes in network transmissions, the DRE module encounters processing wrong packets. Wrong packets are mainly due to TCP checksum collisions. Decode of these packets fails and results in DRE core and process restart.
-In the DRE, the data lookup for some signature might fail as the similar data unit has been flushed out of cache. This might be due to low DRE cache size or large concurrent connections that transfer different data. This lookup failure triggers an assert and that results in a core file and the DRE process restart.
-While it handles a large number of concurrent connections with a large amount of compressible data, the DRE might run out of memory for the buffer allocation that is required in the decode process. This triggers an assert and results in a core file and DRE process restart.
-When the total connections handled by DRE exceeds the WAN acceleration engine (WAE)'s supported connection limit, the DRE core and DRE process restart.?
The core file is created because it hit the development ASSERT check in the code base. Otherwise, all of these scenarios are handled appropriately.
In order to determine what version you have, enter this command:
Cisco Wide Area Application Services Software (WAAS)
Copyright (c) 1999-2013 by Cisco Systems, Inc.
Cisco Wide Area Application Services (universal-k9) Software Release 5.1.1e
(build b13 Jan 29 2014)
Compiled 20:57:42 Jan 29 2014 by gpadhi
Device Id: 00:1a:64:64:b2:4c
System was restarted on Thu Feb 6 09:11:26 2014.
System restart reason: called via cli.
The system has been up for 2 weeks, 5 days, 4 hours, 54 minutes, 41 seconds.
There is no proposed workaround for this problem in version 5.1.1e. This defect is fixed in the 5.1.1f release version that is available on Cisco.com.
Version 5.1.1f posted in WAAS Software Download Center (registered customers only).
See the WAAS Configuration Guide for installation instuctions.
For More Information
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