LARGE single-system Cyrus installs?

[David Carter]

On Fri, 5 Oct 2007, Rob Mueller wrote:

> b) make sure you have the right filesystem (on linux, reiserfs is much 
> better than ext3 even with ext3s dir hashing) and journaling modes

A data point regarding reiserfs/ext3:

We are in the process of moving from reiserfs to ext3 (with dir_index).

ext3 seems to do substantially better than reiserfs for us, especially for 
read heavy loads (squatter runs at least twice as fast as it used do).

I think that this is partly because ext3 does more aggressive read ahead 
(which would be a mixed blessing under heavy load), partly because 
reiserfs suffers from fragmentation. I imagine that there is probably a 
tipping point under the sort of very heavy load that Fastmail see.

data=ordered in both cases. data=journal didn't seem to make any 
difference with ext3. data=journal with reiserfs caused amusing kernel 
memory leaks, which it looks like Fastmail also hit recently. An dedicated 
journal device would probably make a big difference with data=journal.

-- 
David Carter                             Email: David.Carter at ucs.cam.ac.uk
University Computing Service,            Phone: (01223) 334502
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