Hi Paul, i don't have any of those disks, but maybe the SM/PM863 has it's write cache enabled by default and PM883 hasn't. You should check that... I recognized horrible IOPS results on lots of MLC/V-NAND SSDs as soon as they don't use their DWC. Did anything else change in your testing environment, especially HBA/RAID controller? Am 22.02.19 um 14:47 schrieb Paul Emmerich: > Hi, > > it looks like the beloved Samsung SM/PM863a is no longer available > and the replacement is the new SM/PM883. > > We got an 960GB PM883 (MZ7LH960HAJR-00005) here and I ran the > usual fio benchmark... and got horrible results :( > > fio --filename=/dev/sdX --direct=1 --sync=1 --rw=write --bs=4k > --numjobs=1 --iodepth=1 --runtime=60 --time_based > --group_reporting --name=journal-test > > 1 thread - 1150 iops 4 threads - 2305 iops 8 threads - 4200 iops > 16 threads - 7230 iops > > Now that's a factor of 15 or so slower than the PM863a. > > Someone here reports better results with a 883: > https://www.sebastien-han.fr/blog/2014/10/10/ceph-how-to-test-if-your-ssd-is-suitable-as-a-journal-device/ > > Maybe there's a difference between the SM and PM variant of these > new disks for performance? (This wasn't the case for the 863a) > > Does anyone else have these new 883 disks yet? Any experience > reports? > > Paul _______________________________________________ ceph-users > mailing list ceph-users@xxxxxxxxxxxxxx > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > Regards, Oliver Schmitz _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
 |