[Xapian-discuss] Filesystems

[Richard Boulton]

2009/7/13 Arjen van der Meijden <acmmailing at tweakers.net>:
> My colleague is done testing. Please mind that the following results are
> not exact sience and tested with a specific database and with a
> relatively unique system.

Thanks for sharing these results with us.

> Executing about 2500 of our slowest queries with a I/O-dependent forced
> database:
> ext4    766
> xfs     768
> ext3    785
> ext2    795
> reiser3 801
> nilfs   837
> btrfs   849

I'm surprised by the range here.  In particular, from what I know of
their architecture, I wouldn't have expected ext4 and ext3 to be so
different.

> database        run1    run2
> non-compacted   104.8   105.4
> fuller compact  99.5    100.5
> block size 2kb  135.8   136.5
> block size 4kb  136.5   133.9
> block size 8kb  100.9   101.6
> block size 16kb  82.1    81.8
> block size 32kb  79.4    79.0

Coo, that's quite a difference.  Well worth knowing about.  I'd be
fascinated to know whether your older hardware has a significantly
different sweet-spot - I'd expect smaller blocks to result in a bit
less CPU, since skipping through runs in the blocks is currently a bit
expensive (more expensive than I'd like!).

-- 
Richard