On Thu, Sep 15, 2016 at 1:41 AM, Wido den Hollander <wido@xxxxxxxx> wrote: > >> Op 14 september 2016 om 14:56 schreef "Dennis Kramer (DT)" <dennis@xxxxxxxxx>: >> >> >> Hi Burkhard, >> >> Thank you for your reply, see inline: >> >> On Wed, 14 Sep 2016, Burkhard Linke wrote: >> >> > Hi, >> > >> > >> > On 09/14/2016 12:43 PM, Dennis Kramer (DT) wrote: >> >> Hi Goncalo, >> >> >> >> Thank you. Yes, i have seen that thread, but I have no near full osds and >> >> my mds cache size is pretty high. >> > >> > You can use the daemon socket on the mds server to get an overview of the >> > current cache state: >> > >> > ceph daemon mds.XXX perf dump >> > >> > The message itself indicates that the mds is in fact trying to convince >> > clients to release capabilities, probably because it is running out of cache. >> >> My cache is set to mds_cache_size = 15000000, but you are right, it seems >> the complete cache is used, but that shouldn't be a real problem if the >> clients can release the caps in time. Correct me if i'm wrong but the >> cache_size is pretty high compared to the default (100k). I will raise the >> mds_cache_size a bit and see if it helps a bit. >> > > The 100k is very, very conservative. Each cached inode will consume roughly 4k of memory. > > 15.000.000 * 4k =~ 58GB of memory Is that based on empirical testing? Last time we counted (pretty recently!) it was about half that for an inode+dentry: http://docs.ceph.com/docs/master/dev/mds_internals/data-structures/ :) -Greg _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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