Varnish 2.1 + kswapd0 freak out
kb+varnish at slide.com
Sat May 22 00:30:30 CEST 2010
This happens when there is significant memory pressure (heavy network or block I/O exacerbates it) when you have swap disabled. This is a long-standing kernel behavior issue, from my experience. I've seen it with MySQL and other servers, in addition to Varnish.
That being said, perhaps Varnish is initiating a huge object expiry pass that's triggering this problem. If you increase the cli_timeout, it may help prevent the child from being reaped, to probably dubious benefit.
Increasing /proc/sys/vm/min_free_kbytes (by 2-3x) may also help, but it's a dangerous beast. I use 131072 for all of my Varnish instances, for this reason (16-64GB boxes).
You may also find that adding a few hundred meg of swap is the lesser of two evils.
Hope it helps,
On May 20, 2010, at 3:45 PM, Augusto Becciu wrote:
> We don't have swap enabled on these servers.
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