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I have varnish 3, with apache worker/php-fpm, and drupal 7.

Varnish is using high IO and I suspect this has to do with multiple repeated messages like

0 Debug - "lurker: 0xb7505470 1800 0"

when I run varnishlog.

What is this about and how I can fix this issue?

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up vote 1 down vote accepted

The messages you are seeing are not related to the IO. However, there might be two reasons you're seeing high IO. 1) The Linux VM tries to persist the shmlog that Varnish uses for logging to disk. For high performance scenarios you should considering mounting a tmpfs on /var/lib/varnish before starting it up. FreeBSD doesn't need this as the VM there can be instructed not to write stuff to disk.

2) The file backend doesn't work well under high load on rotating media. You should consider malloc.

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read the following mailing list posting on it

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This did not help me find a specific solution yet. – john Oct 14 '11 at 3:08

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