I don’t run Ceph on btrfs, but isn’t this related to the btrfs snapshotting feature ceph uses to ensure a consistent journal?
Jan > On 19 Jun 2015, at 14:26, Lionel Bouton <lionel+c...@bouton.name> wrote: > > On 06/19/15 13:42, Burkhard Linke wrote: >> >> Forget the reply to the list... >> >> -------- Forwarded Message -------- >> Subject: Re: [ceph-users] Unexpected disk write activity with btrfs OSDs >> Date: Fri, 19 Jun 2015 09:06:33 +0200 >> From: Burkhard Linke >> <burkhard.li...@computational.bio.uni-giessen.de> >> <mailto:burkhard.li...@computational.bio.uni-giessen.de> >> To: Lionel Bouton <lionel+c...@bouton.name> <mailto:lionel+c...@bouton.name> >> >> Hi, >> >> On 06/18/2015 11:28 PM, Lionel Bouton wrote: >> > Hi, >> *snipsnap* >> >> > - Disks with btrfs OSD have a spike of activity every 30s (2 intervals >> > of 10s with nearly 0 activity, one interval with a total amount of >> > writes of ~120MB). The averages are : 4MB/s, 100 IO/s. >> >> Just a guess: >> >> btrfs has a commit interval which defaults to 30 seconds. >> >> You can verify this by changing the interval with the commit=XYZ mount >> option. > > I know and I tested commit intervals of 60 and 120 seconds without any > change. As this is directly linked to filestore max sync interval I didn't > report this test result. > > Best regards, > > Lionel > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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