Chasing 503 Guru's

Per Buer perbu at
Thu Dec 2 14:04:09 CET 2010

On Thu, Dec 2, 2010 at 1:28 PM, Simon Males <sime at> wrote:
> Just wanted to share my understanding of tracking down 503 / Guru
> meditation errors.
> Steps:
> 1. Source the XID
> 2. Start varnishlog with -d
> 3. Search the output for the above mentioned XID
> 4. Hopefully the log entry will provide a clue
> Though how long do the shared memory logs exist?

Depends on how much traffic you have. On a busy site it should be a
minute or so. Try logging to disk and you notice how long 80MB (the
default) will last. It will give you an indication on how long the
shmlog lasts. However, the shmlog has some fixed length records so it
wastes a bit of space compared to the output to disk.

> Or is it common practice to write varnishlog to disk in production environments?

No. On Linux the vm get's slightly dazzled by all the IO and will
behave strangely. You can instruct varnishlog to only log 503's. That
might be ideal for you.

Per Buer, Varnish Software
Phone: +47 21 98 92 61 / Mobile: +47 958 39 117 / Skype: per.buer
Varnish makes websites fly!

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