Re: [ceph-users] Huge amount of cephfs metadata writes while only reading data (rsync from storage, to single disk)

On Mon, Mar 19, 2018 at 11:45 PM, Nicolas Huillard wrote: > Le lundi 19 mars 2018 à 15:30 +0300, Sergey Malinin a écrit : >> Default for mds_log_events_per_segment is 1024, in my set up I ended >> up with 8192. >> I calculated that value like IOPS / log segments * 5 seconds

Re: [ceph-users] Huge amount of cephfs metadata writes while only reading data (rsync from storage, to single disk)

On Monday, March 19, 2018 at 18:45, Nicolas Huillard wrote: > > Then I tried to reduce the number of MDS, from 4 to 1,  > Le lundi 19 mars 2018 à 19:15 +0300, Sergey Malinin a écrit : > Forgot to mention, that in my setup the issue gone when I had > reverted back to single MDS and switched

Re: [ceph-users] Huge amount of cephfs metadata writes while only reading data (rsync from storage, to single disk)

Forgot to mention, that in my setup the issue gone when I had reverted back to single MDS and switched dirfrag off. On Monday, March 19, 2018 at 18:45, Nicolas Huillard wrote: > Then I tried to reduce the number of MDS, from 4 to 1, ___ ceph-users

Re: [ceph-users] Huge amount of cephfs metadata writes while only reading data (rsync from storage, to single disk)

Le lundi 19 mars 2018 à 15:30 +0300, Sergey Malinin a écrit : > Default for mds_log_events_per_segment is 1024, in my set up I ended > up with 8192. > I calculated that value like IOPS / log segments * 5 seconds (afaik > MDS performs journal maintenance once in 5 seconds by default). I tried 4096

Re: [ceph-users] Huge amount of cephfs metadata writes while only reading data (rsync from storage, to single disk)

Default for mds_log_events_per_segment is 1024, in my set up I ended up with 8192. I calculated that value like IOPS / log segments * 5 seconds (afaik MDS performs journal maintenance once in 5 seconds by default). On Monday, March 19, 2018 at 15:20, Nicolas Huillard wrote: > I can't find any

Re: [ceph-users] Huge amount of cephfs metadata writes while only reading data (rsync from storage, to single disk)

f of > Nicolas Huillard <nhuill...@dolomede.fr> > Sent: Monday, March 19, 2018 12:01:09 PM > To: ceph-users@lists.ceph.com > Subject: [ceph-users] Huge amount of cephfs metadata writes while > only reading data (rsync from storage, to single disk) > > Hi all, > > I'm e

Re: [ceph-users] Huge amount of cephfs metadata writes while only reading data (rsync from storage, to single disk)

lomede.fr> Sent: Monday, March 19, 2018 12:01:09 PM To: ceph-users@lists.ceph.com Subject: [ceph-users] Huge amount of cephfs metadata writes while only reading data (rsync from storage, to single disk) Hi all, I'm experimenting with a new little storage cluster. I wanted to take advantage of

Re: [ceph-users] Huge amount of cephfs metadata writes while only reading data (rsync from storage, to single disk)

The MDS has to write to its local journal when clients open files, in case of certain kinds of failures. I guess it doesn't distinguish between read-only (when it could *probably* avoid writing them down? Although it's not as simple a thing as it sounds) and writeable file opens. So every file

[ceph-users] Huge amount of cephfs metadata writes while only reading data (rsync from storage, to single disk)

Hi all, I'm experimenting with a new little storage cluster. I wanted to take advantage of the week-end to copy all data (1TB, 10M objects) from the cluster to a single SATA disk. I expected to saturate the SATA disk while writing to it, but the storage cluster actually saturates its network