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] Sent: Thursday, May 23, 2013 11:47 AM To: Khanh. Nguyen Dang Quoc Cc: 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<javascript:_e(%7b%7d,%20'cvml',%20'g...@inktank.com');>] Sent: Thursday, May 23, 2013 10:56 AM To: Khanh. Nguyen Dang Quoc Cc: ceph-users@lists.ceph.com<javascript:_e(%7b%7d,%20'cvml',%20'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<http://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
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