Performance and cheap storage

Kjetil Torgrim Homme kjetilho at
Thu Aug 3 19:51:51 EDT 2006

On Tue, 2006-08-01 at 19:34 -0400, Greg A. Woods wrote:
> Is anyone here running enough concurrent IMAP/SSL connections to know if
> the SSL overhead chews up enough CPU to conflict with something like
> un-accellerated iSCSI (i.e. enough to also justify a crypto
> accellerator, perhaps as well as an iSCSI one)?

not sure if we qualify as big enough, but here goes:  we typically have
3000 concurrent TLS/SSL connections on each Perdition server during peak
hours (although we occasionally see 5000), but the CPU impact is
negligible[1].  at peak, 8% system and 12% user out of 400% CPU
available (this is Dell PE2650 with dual Xeon 1.8 GHz HT) and just 15
Mbps of network traffic in and out -- quite symmetric as you would
expect for a proxy server.  Perdition's connection to Cyrus is
unencrypted, of course.

[1] the main issue is RAM for all those processes. with just 2 GiB RAM
it ran sluggishly once in while during lunchtime, they now have 4 GiB
Kjetil T.

More information about the Info-cyrus mailing list