Yeah, you need to check your disks individually and see how they compare. Sounds like the second one is slower. And you're also getting a bit slower going to 2x replication. -Greg
On Wednesday, May 22, 2013, Khanh. Nguyen Dang Quoc wrote: > I do test follow the below steps:**** > > ** ** > > + create image with size 100Gb in pool data **** > > + after that, I do map that image on one server.**** > > + and do mkfs.xfs /dev/rbd0 -> mount /deve/rbd0 /mnt**** > > + I do the write benchmark on that mount point with dd tool :**** > > ** ** > > dd if=/dev/zero of=/mnt/good2 bs=1M count=10000 oflag=direct**** > > ** ** > > ** ** > > *From:* Gregory Farnum [mailto:g...@inktank.com <javascript:_e({}, > 'cvml', 'g...@inktank.com');>] > *Sent:* Thursday, May 23, 2013 11:47 AM > *To:* Khanh. Nguyen Dang Quoc > *Cc:* ceph-users@lists.ceph.com <javascript:_e({}, 'cvml', > 'ceph-users@lists.ceph.com');> > *Subject:* Re: [ceph-users] performance degradation issue**** > > ** ** > > "rados bench write", you mean? Or something else?**** > > ** ** > > Have you checkd the disk performance of each OSD outside of Ceph? In > moving from one to two OSDs your performance isn't actually going to go up > because you're replicating all the data. It ought to stay flat rather than > dropping, but my guess is your second disk is slow. > > On Wednesday, May 22, 2013, Khanh. Nguyen Dang Quoc wrote:**** > > Hi Greg,**** > > **** > > It’s the write benchmark.. **** > > **** > > Regards**** > > Khanh**** > > **** > > *From:* Gregory Farnum [mailto:g...@inktank.com] > *Sent:* Thursday, May 23, 2013 10:56 AM > *To:* Khanh. Nguyen Dang Quoc > *Cc:* ceph-users@lists.ceph.com > *Subject:* Re: [ceph-users] performance degradation issue**** > > **** > > What's the benchmark?**** > > -Greg > > On Wednesday, May 22, 2013, Khanh. Nguyen Dang Quoc wrote:**** > > Dear all,**** > > **** > > now i faced one issue in ceph block device: performance degradation**** > > **** > > ceph version 0.61.2 (fea782543a844bb277ae94d3391788b76c5bee60)**** > > ceph status **** > > **** > > health HEALTH_OK**** > > monmap e1: 2 mons at {a=49.213.67.204:6789/0,b=49.213.67.203:6789/0}, > election epoch 20, quorum 0,1 a,b**** > > osdmap e53: 2 osds: 2 up, 2 in**** > > pgmap v535: 576 pgs: 576 active+clean; 11086 MB data, 22350 MB used, 4437 > GB / 4459 GB avail**** > > mdsmap e29: 1/1/1 up {0=a=up:active}, 1 up:standby**** > > **** > > I do benchmark with one osd, I receive the io speed is about 190MB/s**** > > **** > > But When i add more osd, replicate size =2 , the write performance > degradated is about 90MB/s**** > > **** > > Follow the pratice, the write performance must be increated as adding more > osd but I can't receive that. :(**** > > anyone can you help me check what's wrong in config file or anything else? > **** > > **** > > Regards,**** > > Khanh Nguyen**** > > > > -- > Software Engineer #42 @ http://inktank.com | http://ceph.com**** > > > > -- > Software Engineer #42 @ http://inktank.com | http://ceph.com**** > -- Software Engineer #42 @ http://inktank.com | http://ceph.com
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