[ceph-users] Experiences with the Samsung SM/PM883 disk?

Paul Emmerich paul.emmerich at croit.io
Tue Mar 5 02:07:58 PST 2019


Well, tried a different disk and basically got the same results as Jacob.
So I've just had a bad disk there (server was fine as other disks work in it).


Paul

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Paul Emmerich

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On Sun, Feb 24, 2019 at 8:55 PM Paul Emmerich <paul.emmerich at croit.io> wrote:
>
> That sounds more like the result I expected, maybe there's something
> wrong with my disk or server (other disks perform fine, though).
>
> Paul
>
>
>
> Paul
>
> On Fri, Feb 22, 2019 at 8:25 PM Jacob DeGlopper <jacob at mhem.net> wrote:
> >
> > What are you connecting it to?  We just got the exact same drive for
> > testing, and I'm seeing much higher performance, connected to a
> > motherboard 6 Gb SATA port on a Supermicro X9 board.
> >
> > [root at centos7 jacob]# smartctl -a /dev/sda
> >
> > Device Model:     Samsung SSD 883 DCT 960GB
> > Firmware Version: HXT7104Q
> > SATA Version is:  SATA 3.2, 6.0 Gb/s (current: 6.0 Gb/s)
> >
> > [root at centos7 jacob]# fio --filename=/dev/sda --direct=1 --sync=1
> > --rw=write --bs=4k --numjobs=1 --iodepth=1 --runtime=60 --time_based
> > --group_reporting --name=journal-test
> >
> > write: IOPS=15.9k, BW=62.1MiB/s (65.1MB/s)(3728MiB/60001msec)
> >
> > 8 processes:
> >
> > write: IOPS=58.1k, BW=227MiB/s (238MB/s)(13.3GiB/60003msec)
> >
> >
> > On 2/22/19 8:47 AM, Paul Emmerich wrote:
> > > 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 at lists.ceph.com
> > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
> > _______________________________________________
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> > ceph-users at lists.ceph.com
> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com


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