Problems with load balancing cluster on GFS

[Jens Hoffrichter]

Hello Jorey

2008/6/5 Jorey Bump <list at joreybump.com>:

>> At first I thought that this was a problem related to entropy, but it
>> even persisted after I turned off "allowapop", and unconfigured
>> everything relating to TLS (as SSL/TLS will be handled completely by
>> the perdition, we don't need it)
>
> To rule it out completely, watch it during your test:
>
>  watch -n 0 'cat /proc/sys/kernel/random/entropy_avail'
>
> It might start blocking when it gets as low as 100 (healthy seems to be
> above 1000). If you're at the console (not a remote terminal), type on the
> keyboard to add entropy and see if this helps. If it does, you may have a
> cyrus-sasl that uses /dev/random (the default). Check the source RPM to
> verify, and adjust it to use /dev/urandom to stop the blocking.
Thanks for that hint, I didn't know that you could monitor available
entropy that way, that is very useful to know :)

But it doesn't seem to be related to entropy. Though on one of the
nodes entropy is usually quite low (between 100 and 300), it never
drops below the 100 mark, and when running a load test, that node and
another failed, and on the one failing was more than 3000 entropy
available.

To rule it out completely I started rngd on all the nodes, feeding
from /dev/urandom (I know, not perfect, but better than nothing ;) ),
but that didn't change anything. And I checked the compilation
settings for my cyrus-sasl package, it already takes /dev/urandom as
entropy source. So I think I can rule it out mostly....

But thanks for the input.

Regards,
Jens