[squid-users] Squid uses way too much RAM and starts swapping ...

Hi,

I am currently using squid 3.1.12 as forward-proxy without
harddisk-caching (only RAM is used for caching). Each server is
running on RHEL5.5 and is pretty strong (16 CPUs, 28GB RAM), but each
servers starts swapping a few days after start. The workaround at the
moment is to reboot the server once a week, which I don't really like.
But swapping leads to serious side effects, e.g. performance troubles,
...

way too much swapping:
http://imageshack.us/m/52/6149/memoryday.png

I already read a lot of posts and mails for similar problems, but
unfortunately, I was not able to solve this problem. I added following
infos to my squid.conf-file:
# cache specific settings
cache_replacement_policy heap LFUDA
cache_mem 1600 MB
memory_replacement_policy heap LFUDA
maximum_object_size_in_memory 2048 KB
memory_pools off
cache_swap_low 85
cache_swap_high 90

(There are four squid instances per server, which means that 1600*4 =
6400MB RAM used for caching, which is not even 1/4 of the total
available amount of RAM. Plenty enough, don't you think?)

Very strange are the negative values (Memory usage for squid via
mallinfo():) from the output below. Maybe that is a reason for running
out of RAM?

HTTP/1.0 200 OK
Server: squid/3.1.12
Mime-Version: 1.0
Date: Wed, 11 May 2011 07:06:10 GMT
Content-Type: text/plain
Expires: Wed, 11 May 2011 07:06:10 GMT
Last-Modified: Wed, 11 May 2011 07:06:10 GMT
X-Cache: MISS from xlsqip03_1
Via: 1.0 xlsqip03_1 (squid/3.1.12)
Connection: close

Squid Object Cache: Version 3.1.12
Start Time: Wed, 27 Apr 2011 11:01:13 GMT
Current Time: Wed, 11 May 2011 07:06:10 GMT
Connection information for squid:
        Number of clients accessing cache: 1671
        Number of HTTP requests received: 16144359
        Number of ICP messages received: 0
        Number of ICP messages sent: 0
        Number of queued ICP replies: 0
        Number of HTCP messages received: 0
        Number of HTCP messages sent: 0
        Request failure ratio: 0.00
        Average HTTP requests per minute since start: 810.3
        Average ICP messages per minute since start: 0.0
        Select loop called: 656944758 times, 1.820 ms avg
Cache information for squid:
        Hits as % of all requests: 5min: 17.4%, 60min: 18.2%
        Hits as % of bytes sent: 5min: 45.6%, 60min: 39.9%
        Memory hits as % of hit requests: 5min: 86.1%, 60min: 88.9%
        Disk hits as % of hit requests: 5min: 0.0%, 60min: 0.0%
        Storage Swap size: 0 KB
        Storage Swap capacity: 0.0% used, 0.0% free
        Storage Mem size: 1622584 KB
        Storage Mem capacity: 100.0% used, 0.0% free
        Mean Object Size: 0.00 KB
        Requests given to unlinkd: 0
Median Service Times (seconds) 5 min 60 min:
        HTTP Requests (All): 0.01648 0.01235
        Cache Misses: 0.05046 0.04277
        Cache Hits: 0.00091 0.00091
        Near Hits: 0.01469 0.01745
        Not-Modified Replies: 0.00000 0.00091
        DNS Lookups: 0.00190 0.00190
        ICP Queries: 0.00000 0.00000
Resource usage for squid:
        UP Time: 1195497.286 seconds
        CPU Time: 22472.507 seconds
        CPU Usage: 1.88%
        CPU Usage, 5 minute avg: 5.38%
        CPU Usage, 60 minute avg: 5.44%
        Process Data Segment Size via sbrk(): 3145032 KB
        Maximum Resident Size: 0 KB
        Page faults with physical i/o: 8634
Memory usage for squid via mallinfo():
        Total space in arena: -1049140 KB
        Ordinary blocks: -1277813 KB 87831 blks
        Small blocks: 0 KB 0 blks
        Holding blocks: 2240 KB 5 blks
        Free Small blocks: 0 KB
        Free Ordinary blocks: 228673 KB
        Total in use: -1275574 KB 122%
        Total free: 228674 KB -22%
        Total size: -1046900 KB
Memory accounted for:
        Total accounted: -1375357 KB 131%
        memPool accounted: 2818947 KB -269%
        memPool unaccounted: -3865847 KB 0%
        memPoolAlloc calls: 111
        memPoolFree calls: 8322084644
File descriptor usage for squid:
        Maximum number of file descriptors: 1024
        Largest file desc currently in use: 563
        Number of file desc currently in use: 472
        Files queued for open: 0
        Available number of file descriptors: 552
        Reserved number of file descriptors: 100
        Store Disk files open: 0
Internal Data Structures:
         96996 StoreEntries
         96996 StoreEntries with MemObjects
         96980 Hot Object Cache Items
             0 on-disk objects

Has anyone experienced similar things or does even know a solution?

Thank you and best regards!
Peter
Received on Wed May 11 2011 - 07:19:20 MDT