Re: Very intensive I/O under mon process

[Joao Eduardo Luis <joao.luis@inktank.com>]

On 01/02/2013 03:40 PM, Andrey Korolyov wrote:
> I have just observed that ceph-mon process, at least bobtail one, has
> an extremely high density of writes - times above _overall_ cluster
> amount of writes, measured by qemu driver(and they are very close to
> be fair). For example, test cluster of 32 osds have 7.5 MByte/s of
> writes on each mon node having overall amount about 1.5 Mbyte/s and
> dev- with only three osds has values is about 1Mbyte/s with
> accumulated real write bandwidth of tens of kilobytes per second.
>
> I`m afraid if this is normal, I may hit a limit of spinning storage
> increasing test cluster, say, twenty times up of number of osd and
> related ``idle'' write bandwidth.

High debugging levels (specially 'debug ms', 'debug mon' or 'debug 
paxos') should significantly increase IO on the monitors. Might that be 
the case?

   -Joao