Re: Ceph RBD performance - random writes

[Mark Kirkwood <mark.kirkwood@catalyst.net.nz>]

On 09/08/12 12:43, Mark Kirkwood wrote:
>
>>
>
>
> I tried out a raft of xfs config changes and also made the Ceph 
> journal really big (10G):
>
> $ mkfs.xfs -f -l internal,size=1024m -d agcount=4 /dev/sd[b,c]2
>
> + mount options with nobarrier,logbufs=8
>
> The results improved a little, but still very slow for small request 
> sizes...

Some more careful analysis showed that all the benefit derived from the 
ceph storage reinit after the filesystem was remade, so going back 
gradually to the default filesystem options (mkfs.xfs, default mount 
with noatime, discard) and 2G journal results in the same numbers as I 
posted with the tweaked settings.

So sorry, appears to be nothing gained (on this system anyway) from said 
tweaking.

Regards

Mark