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[Xen-users] Low /proc/sys/kernel/random/entropy_avail on domU

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Subject: [Xen-users] Low /proc/sys/kernel/random/entropy_avail on domU
From: "cornet@xxxxxxxxxx" <cornet@xxxxxxxxxx>
Date: Thu, 01 Dec 2005 17:13:53 +0000
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This problem came about when I noticed exim, on a domU, holding mail in its queue for days before delivering.

After a bit of debugging then I found gnutls was taking ages to calculate its keys.

So disabled TLS in exim and works fine.

Then I had another xen domU doing exactly the same thing so I did some more digging and came up with this post:


sure enough
/proc/sys/kernel/random/entropy_avail = 0
when mail is stuck in the queue.

Now I've stopped exim from using TLS again, and I don't think there is much else running that could be using up the entropy, but the entropy is still low, max I've seen it is ~300. (Compaired to 3000+ on other non-xen boxes).

Both these servers are similar set up (although I didn't setup the 2nd one):

Debian - Sarge as dom0 and domU.
Xen 2.0 compiled from source.

So why do these boxes have low entropy, I've never seen this on non-xen, hence posting here.

Ideas welcome.


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