Re: Ceph performance

[Roman Alekseev <rs.alekseev@gmail.com>]

On 30.10.2012 14:47, Maciej Gałkiewicz wrote:
>> ServerA(mon+osd):
>> Filesystem            Size  Used Avail Use% Mounted on
>> /dev/sda1             9.2G  2.4G  6.4G  27% /
>> tmpfs                 5.9G     0  5.9G   0% /lib/init/rw
>> udev                  5.9G  148K  5.9G   1% /dev
>> tmpfs                 5.9G     0  5.9G   0% /dev/shm
>> /dev/sda7             674G  483M  629G   1% /var/lib/ceph/mon
>> /dev/sda6             917G  2.4G  868G   1% /var/lib/ceph/osd/ceph-4
> I see that you have separate partitions for osd and mon. Some of them
> are on the same disk as OS. I would strongly recommend having separate
> disk (not just partition) for each osd.
>
> There is another problem probably more important. By default journal
> is stored in /var/lib/ceph/osd/$cluster-$id/journal which means you
> have data and journal on the same disk. It is what slows you down the
> most. I was amazed how faster the cluster can be just by putting the
> journal somewhere else (tmpfs - only for tests, another disk). From my
> experiance, there is no need for separate disk for mon. It can go with
> OS.
>
> Run rados bench everytime you make an improvement in your cluster.
>
Oops, it's actually true!!!

Give me a moment to check this out and thank you for opening my eyes.
Let me to notify you about the results of implementing your recommendations.

I'm going to completely rebuild my cluster. Thank so much.

-- 
Kind regards,

R. Alekseev

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