On Wed, Jan 2, 2013 at 8:00 PM, Joao Eduardo Luis <joao.luis@xxxxxxxxxxx> wrote: > 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? Nope, all debug levels, including mons are set to 0/0. I also see that the ``no-client'' cluster shows a very small amount of such writes under mon, 10-20kByte/s, and one idle client (writing couple of bytes without O_SYNC) raise this value times up to ~200kB/s and so on, so may be I`m wrong before and writes correlate with amount of clients too(six clients plus three control nodes accessing via API in the context of previous message for both environments). -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
