On the current setup we're running into a problem with Varnish, we're running a CentOS 5.7 x86_64 xenpv, with Cpanel WHM, hosted at VPS.net.

Sometimes we will recieve a Guru Meditation from Varnish, and when we look in the varnishlog with the following command varnishlog -d -c -m TxStatus:503 it returns output similar to the following:

   15 VCL_call     c recv
   15 VCL_acl      c NO_MATCH devs
   15 VCL_return   c pass
   15 VCL_call     c hash
   15 Hash         c ****
   15 Hash         c *************
   15 VCL_return   c hash
   15 VCL_call     c pass pass
   15 Backend      c 12 default default
   15 TTL          c 1835862523 RFC 0 -1 -1 1332454056 0 1332454055 375007920 0
   15 VCL_call     c fetch hit_for_pass
   15 ObjProtocol  c HTTP/1.1
   15 ObjResponse  c OK
   15 ObjHeader    c Date: Thu, 22 Mar 2012 22:07:35 GMT
   15 ObjHeader    c Server: Apache/2.2.21 (Unix) mod_ssl/2.2.21 OpenSSL/0.9.8e-fips-rhel5 mod_bwlimited/1.4 mod_fcgid/2.3.6
   15 ObjHeader    c X-Powered-By: PHP/5.3.9
   15 ObjHeader    c Expires: Thu, 19 Nov 1981 08:52:00 GMT
   15 ObjHeader    c Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
   15 ObjHeader    c Pragma: no-cache
   15 ObjHeader    c Content-Type: text/html; charset=utf-8
   15 ObjHeader    c X-Cacheable: NO:Cache-Control=private
   15 FetchError   c chunked read_error: 12 (Could not get storage)
   15 VCL_call     c error deliver
   15 VCL_call     c deliver deliver

As far as I have could gather, we could try increasing the nuke_limit, but currently we have a nuke_limit of 500, and when running varnishstat -1 -f n_lru_nuked we "only" get a total of 1031, even though we have seen the error happen on several pages.

When we then run top to see how much memory Varnish is using, it only shows that it is using 763m, although we've set it to be allowed to use 1200m.

Any ideas of what the problem can be?