Internet outage with messages "RW: SSL connection to server failed" in the Event Log
Article ID: 236318
Updated On:
Products
Issue/Introduction
"RW: SSL connection to server failed" found in the event log is an indication that the Retrieval Workers (RWs) are trying to get out to the Internet but failing. Retrieval workers are processes that refresh cached objects and perform pipelining.
Active refreshing of cached objects have been disabled by default since SGOS 6.3.x. Pipelining was disabled by default since SGOS 6.7.1.1 since it increases CPU and the benefit is limited (release notes attached).
Cause
Multiple RWs were seen ramping up CPU utilization to a point where incoming TCP connections were not processed as a result of being a lower priority, thus causing an outage. This made new incoming connections queue up. The TCP receive queue can be tracked with statistic labeled TCP1.186 in the Sysinfo and Snapshot_sysinfo_Stats.
Resolution
Disabling Active Refresh and pipelining resolved the outage and RW events are no longer seen in the Event Logs.
To disable Active Refreshing:
1. SSH to the proxy
2. Issue the following command
conf t
caching
refresh bandwidth 0
To disable pipelining:
Select Configuration > Proxy Settings > HTTP Proxy > Acceleration in the Management Console. Under Acceleration Settings, clear the checkboxes beside the following options:
- Pipeline embedded objects client request
- Pipeline redirects for client request
- Pipeline embedded objects in prefetch request
- Pipeline redirects for prefetch request
Click Apply to save your changes.
The associated CLI commands to disable pipelining are as follows:
http no pipeline client requests http no pipeline client redirects http no pipeline prefetch requests http no pipeline prefetch redirects
Additional Information
One can check if RW is enabled by issuing the command in CLI
en
conf t
caching
view
RW disabled CLI output:
ProxySG#(config caching)view
Refresh:
Refreshing is disabled
Policies:
Automatically regulate caching to maximize performance
Do not cache objects larger than 10000 megabytes
Cache negative responses for 0 minutes
Let the ProxySG Appliance manage freshness
FTP caching:
Caching FTP objects is enabled
FTP objects with last modified date, cached for 10% of last modified time
FTP objects without last modified date, initially cached for 24 hours
RW Enabled CLI output:
ProxySG#(config caching)view
Refresh:
Estimated access freshness is 100.0%
Use no more than 1 kilobits/sec for bandwidth
Current bandwidth used is 0 kilobits/sec
Policies:
Automatically regulate caching to maximize performance
Do not cache objects larger than 10000 megabytes
Cache negative responses for 0 minutes
Let the ProxySG Appliance manage freshness
FTP caching:
Caching FTP objects is enabled
FTP objects with last modified date, cached for 10% of last modified time
FTP objects without last modified date, initially cached for 24 hours
Attachments
Feedback
