File storage problem.

[Sébastien FOUTREL]

Hello,

We use Varnish 2.0.6 in a production site that do about 100Mb/s and 1K Hits/s per cache.



We found a strange phenomon when we added some 24H TTL to images.

The file storage seems to have some garbage collection that deeply impact performances when freeing some large amount of cache.

We initialy used 8Gb file storage and encountered some GC at about 80% usage that freed almost all file storage (monitored with cacti using sm_balloc,sm_bfree values).

We tried on one of our cache to test with 32GB and 64GB files but same happened even worse because on the 64GB file it did the GC at 30GB and freed until sm_balloc reached 2GB.

We do not understand what is that and and to control it so if someone as ideas around that problem ?



These are some infos about the server :

Hardware/OS/updates is same on cache02 and cache05



root at cache02:~# ps auxwww|grep varnishd

root     22731  0.0  0.0 110836  1164 ?        Ss   Apr09   0:00 /usr/sbin/varnishd -P /var/run/varnishd.pid -a :80 -f /etc/varnish/default.vcl -T :6082 -t 60 -w 100,1000,120 -s file,/var/lib/varnish/cache02/varnish_storage.bin,8G

nobody   22732 11.5 86.9 10972872 7109076 ?    Sl   Apr09 535:23 /usr/sbin/varnishd -P /var/run/varnishd.pid -a :80 -f /etc/varnish/default.vcl -T :6082 -t 60 -w 100,1000,120 -s file,/var/lib/varnish/cache02/varnish_storage.bin,8G

root at cache05:~# uname -a

Linux cache05 2.6.27-11-generic #1 SMP Thu Jan 29 19:28:32 UTC 2009 x86_64 GNU/Linux

root at cache05:~# free

             total       used       free     shared    buffers     cached

Mem:       8178736    8130800      47936          0      30188    6606748

-/+ buffers/cache:    1493864    6684872

Swap:            0          0          0

Graphs for cache02 and cache05

[cid:image001.png at 01CADA2A.BEDC7140]

[cid:image002.png at 01CADA2B.30A09680]

[cid:image003.png at 01CADA2B.30A09680]



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[cid:image005.png at 01CADA2B.8893FFD0]

[cid:image006.png at 01CADA2B.8893FFD0]



Sorry for the email size.



--

Sébastien FOUTREL


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