[squid-users] File Descriptor Issue

Hi:

I am running squid version 3.3.8 on CentOS v6.5.

I have an issue regarding file descriptors. Our proxy has run into an
issue the past few days (everyone streaming FIFA soccer I believe)
where we receive the following error:

WARNING! Your cache is running out of filedescriptors

At this point the CPU usage of each squid worker spikes to 100% and
the SNMP agent becomes unavailable.

I was able to get some information from squidclient mgr:info.

My question is around the file descriptor statistics:

When the issue is happening it reports:

File descriptor usage for squid:
        Maximum number of file descriptors: 16384
        Largest file desc currently in use: 548
        Number of file desc currently in use: 540
        Files queued for open: 0
        Available number of file descriptors: 15844
        Reserved number of file descriptors: 100
        Store Disk files open: 0

After a restart of squid it reports the following:

File descriptor usage for squid:
        Maximum number of file descriptors: 65536
        Largest file desc currently in use: 516
        Number of file desc currently in use: 475
        Files queued for open: 0
        Available number of file descriptors: 65061
        Reserved number of file descriptors: 400
        Store Disk files open: 0

The ulimit setting for the OS is 8192 for open files. According to the
documentation for max_filedescriptors (which I don't have set in my
squid.conf) the default value is the ulimit value. Therefore why on
first startup does it list the max FD of 65k? Also, when the issue
arises why does it end up dropping to 16k? According to the output
above there is at any point roughly only 1k FD in use, so why is squid
reporting that it is running out of FD?

Any assistance would be appreciated.

Thanks
Received on Tue Jun 24 2014 - 17:01:20 MDT