7 Jun
2010
7 Jun
'10
5:50 p.m.
Hi,
If you're on IRC, or follow me/bitfolk on twitter
or on Facebook
you're probably bored to tears hearing about this, but just in case
there's some of you who aren't..
I've been investigating the issue of lack of entropy in virtual
machines recently, and have gone into it in some detail in the
following two blog postings:
http://strugglers.net/~andy/blog/2010/06/06/adventures-in-entropy-part-1/
Thanks for this Andy!
I've been running
watch -n 0.25 cat /proc/sys/kernel/random/entropy_avail
...as recommended buy Hugo in the comments and my VPS fills up with
entropy very quickly.
When I first started looking it was at 185 but now it seems stuck at
3585. If I do things over imaps it will drop briefly and then refill to
a stable 3585 over the next few seconds.
On my desktop machine, a Core 2 Duo with an Intel TPM and apparently a
load of crypto gubbins, my entropy sits around 140 the entire time and
struggles to get above 200.
/proc/sys/kernel/random/{read,write}_wakeup_threshold are set at 64 and
128 respectively on both machines.
In the past I've seen smtps mail submissions stall for arbitrary lengths
of time and very occasionally even timeout completely. I've always put
this down to a lack of entropy: now I wonder which end was lacking.
Regards,
@ndy
--
andyjpb(a)ashurst.eu.org
http://www.ashurst.eu.org/
0x7EBA75FF