Hello, On Tue, 14 Jun 2016 06:47:03 +0100 Nick Fisk wrote:
> osd_tier_promote_max_objects_sec > and > osd_tier_promote_max_bytes_sec > Right, I remember those from February and May. And I'm not asking for this feature, but personally I would have split that in read and write promotes. As in, throttle promotes done to satisfy reads, but not for writes (as that will benefit from the faster pool a lot more). > is what you are looking for, I think by default its set to 5MB/s, which > would roughly correlate to why you are only seeing around 8 objects each > time being promoted. This was done like this as too many promotions hurt > performance, so you don't actually want to promote on every IO. > Well, I do, but yeah. Obviously the defaults were picked to be on the safe side of things, though anybody running a cache tier worth its salt will be able to handle more than 5MB/s. But never mind that, since these parameters are not documented on the cache-tiering documentation page new users like Oliver will get unexpected results. And existing cache-tier users will be rudely surprised, as this isn't mentioned in the changelog either... Christian > > -----Original Message----- > > From: ceph-users [mailto:ceph-users-boun...@lists.ceph.com] On Behalf > > Of Christian Balzer > > Sent: 14 June 2016 02:00 > > To: ceph-users@lists.ceph.com > > Subject: Re: [ceph-users] strange cache tier behaviour with cephfs > > > > > > Hello, > > > > On Tue, 14 Jun 2016 02:52:43 +0200 Oliver Dzombic wrote: > > > > > Hi Christian, > > > > > > if i read a 1,5 GB file, which is not changing at all. > > > > > > Then i expect the agent to copy it one time from the cold pool to the > > > cache pool. > > > > > Before Jewel, that is what you would have seen, yes. > > > > Did you read what Sam wrote and me in reply to him? > > > > > In fact its every time making a new copy. > > > > > Is it? > > Is there 1.5GB of data copied into the cache tier each time? > > An object is 4MB, you only had 8 in your first run, then 16... > > > > > I can see that by increasing disc usage of the cache and the > > > increasing object number. > > > > > > And the non existing improvement of speed. > > > > > That could be down to your network or other factors on your client. > > > > Christian > > -- > > Christian Balzer Network/Systems Engineer > > ch...@gol.com Global OnLine Japan/Rakuten Communications > > http://www.gol.com/ > > _______________________________________________ > > ceph-users mailing list > > ceph-users@lists.ceph.com > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > -- Christian Balzer Network/Systems Engineer ch...@gol.com Global OnLine Japan/Rakuten Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
