Re: Using other filesystems than btrfs with Ceph

[Peter Niemayer <niemayer@isg.de>]

On 06/11/2010 06:26 PM, Gregory Farnum wrote:
>> Also, the documentation in the Wiki does not mention what would need
>> to be configured differently if another filesystem was to be used -
>> what would I have to use instead of "btrfs devs = /dev/sdy"?
> You can look at the ceph.conf file produced by the vstart script for a
> non-btrfs example -- just use
> osd data = path
> osd journal = path2
> osd journal size = [# in MB]

Thanks for this info!


> Well, it's possible that you could improve Ceph's performance in
> certain workloads by using different underlying filesystems, but in
> general Ceph's interfaces and protocols are going to matter a lot
> more, and btrfs works very well with it.

It would be interesting to me what would be a factor of slow-down
to be expected when setting up a minimalistic one-node-Ceph service,
where all daemons run on localhost, and just one local filesystem
is created for the OSD, in comparison to using btrfs directly on that
local filesystem?

Would you expect a significant decrease in sequential read/write throughput?
And what about latencies for small reads/writes?

I wonder what would be an acceptable design-goal when ruling
out physical network equipment or cabling for the moment...


Regards,

Peter Niemayer