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
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