Not sure what exact brands of samsung you have, but i've got the 840 Pro and it sucks big time. its is slow and unreliable and halts to a stand still over a period of time due to the trimming issue. Even after i've left unreserved like 50% of the disk.
Unlike the Intel disks (even the consumer brand like 520 and 530 are just way better. I will stay away from any samsung drives in the future. Andrei ----- Original Message ----- > From: "Sumit Gaur" <sumitkg...@gmail.com> > To: "Irek Fasikhov" <malm...@gmail.com> > Cc: ceph-users@lists.ceph.com > Sent: Friday, 13 February, 2015 1:09:38 PM > Subject: Re: [ceph-users] ceph Performance with SSD journal > Hi Irek, > I am using v0.80.5 Firefly > -sumit > On Fri, Feb 13, 2015 at 1:30 PM, Irek Fasikhov < malm...@gmail.com > > wrote: > > Hi. > > > What version? > > > 2015-02-13 6:04 GMT+03:00 Sumit Gaur < sumitkg...@gmail.com > : > > > > Hi Chir, > > > > > > Please fidn my answer below in blue > > > > > > On Thu, Feb 12, 2015 at 12:42 PM, Chris Hoy Poy < ch...@gopc.net > > > > > > > wrote: > > > > > > > Hi Sumit, > > > > > > > > > > A couple questions: > > > > > > > > > > What brand/model SSD? > > > > > > > > > samsung 480G SSD(PM853T) having random write 90K IOPS (4K, > > > 368MBps) > > > > > > > What brand/model HDD? > > > > > > > > > 64GB memory, 300GB SAS HDD (seagate) , 10Gb nic > > > > > > > Also how they are connected to controller/motherboard? Are they > > > > sharing a bus (ie SATA expander)? > > > > > > > > > no , They are connected with local Bus not the SATA expander. > > > > > > > RAM? > > > > > > > > > 64GB > > > > > > > Also look at the output of "iostat -x" or similiar, are the > > > > SSDs > > > > hitting 100% utilisation? > > > > > > > > > No, SSD was hitting 2000 iops only. > > > > > > > I suspect that the 5:1 ratio of HDDs to SDDs is not ideal, you > > > > now > > > > have 5x the write IO trying to fit into a single SSD. > > > > > > > > > I have not seen any documented reference to calculate the ratio. > > > Could you suggest one. Here I want to mention that results for > > > 1024K > > > write improve a lot. Problem is with 1024K read and 4k write . > > > > > > SSD journal 810 IOPS and 810MBps > > > > > > HDD journal 620 IOPS and 620 MBps > > > > > > > I'll take a punt on it being a SATA connected SSD (most > > > > common), > > > > 5x > > > > ~130 megabytes/second gets very close to most SATA bus limits. > > > > If > > > > its a shared BUS, you possibly hit that limit even earlier > > > > (since > > > > all that data is now being written twice out over the bus). > > > > > > > > > > cheers; > > > > > > > > > > \Chris > > > > > > > > > > From: "Sumit Gaur" < sumitkg...@gmail.com > > > > > > > > > > > To: ceph-users@lists.ceph.com > > > > > > > > > > Sent: Thursday, 12 February, 2015 9:23:35 AM > > > > > > > > > > Subject: [ceph-users] ceph Performance with SSD journal > > > > > > > > > > Hi Ceph -Experts, > > > > > > > > > > Have a small ceph architecture related question > > > > > > > > > > As blogs and documents suggest that ceph perform much better if > > > > we > > > > use journal on SSD . > > > > > > > > > > I have made the ceph cluster with 30 HDD + 6 SSD for 6 OSD > > > > nodes. > > > > 5 > > > > HDD + 1 SSD on each node and each SSD have 5 partition for > > > > journaling 5 OSDs on the node. > > > > > > > > > > Now I ran similar test as I ran for all HDD setup. > > > > > > > > > > What I saw below two reading goes in wrong direction as > > > > expected > > > > > > > > > > 1) 4K write IOPS are less for SSD setup, though not major > > > > difference > > > > but less. > > > > > > > > > > 2) 1024K Read IOPS are less for SSD setup than HDD setup. > > > > > > > > > > On the other hand 4K read and 1024K write both have much better > > > > numbers for SSD setup. > > > > > > > > > > Let me know if I am missing some obvious concept. > > > > > > > > > > Thanks > > > > > > > > > > sumit > > > > > > > > > > _______________________________________________ > > > > > > > > > > ceph-users mailing list > > > > > > > > > > ceph-users@lists.ceph.com > > > > > > > > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > > > > > _______________________________________________ > > > > > > ceph-users mailing list > > > > > > ceph-users@lists.ceph.com > > > > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > -- > > > С уважением, Фасихов Ирек Нургаязович > > > Моб.: +79229045757 > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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