Thank you. Here I have NVMes from Intel. but as the support of these NVMes not there from Intel, we decided not to use these NVMes as a journal. Btw, if we split this SSD with multiple OSD (for ex: 1 SSD with 4 or 2 OSDs), is this help any performance numbers? On Sun, Aug 20, 2017 at 9:33 AM, Christian Balzer <chibi@xxxxxxx> wrote: > > Hello, > > On Sat, 19 Aug 2017 23:22:11 +0530 M Ranga Swami Reddy wrote: > >> SSD make details : SSD 850 EVO 2.5" SATA III 4TB Memory & Storage - >> MZ-75E4T0B/AM | Samsung >> > And there's your answer. > > A bit of googling in the archives here would have shown you that these are > TOTALLY unsuitable for use with Ceph. > Not only because of the horrid speed when used with/for Ceph journaling > (direct/sync I/O) but also their abysmal endurance of 0.04 DWPD over 5 > years. > Or in other words 160GB/day, which after the Ceph journal double writes > and FS journals, other overhead and write amplification in general > probably means less that effective 40GB/day. > > In contrast the lowest endurance DC grade SSDs tend to be 0.3 DWPD and > more commonly 1 DWPD. > And I'm not buying anything below 3 DWPD for use with Ceph. > > Your only chance to improve the speed here is to take the journals off > them and put them onto fast and durable enough NVMes like the Intel DC P > 3700 or at worst 3600 types. > > That still leaves you with their crappy endurance, only twice as high than > before with the journals offloaded. > > Christian > >> On Sat, Aug 19, 2017 at 10:44 PM, M Ranga Swami Reddy >> <swamireddy@xxxxxxxxx> wrote: >> > Yes, Its in production and used the pg count as per the pg calcuator @ ceph.com. >> > >> > On Fri, Aug 18, 2017 at 3:30 AM, Mehmet <ceph@xxxxxxxxxx> wrote: >> >> Which ssds are used? Are they in production? If so how is your PG Count? >> >> >> >> Am 17. August 2017 20:04:25 MESZ schrieb M Ranga Swami Reddy >> >> <swamireddy@xxxxxxxxx>: >> >>> >> >>> Hello, >> >>> I am using the Ceph cluster with HDDs and SSDs. Created separate pool for >> >>> each. >> >>> Now, when I ran the "ceph osd bench", HDD's OSDs show around 500 MB/s >> >>> and SSD's OSD show around 280MB/s. >> >>> >> >>> Ideally, what I expected was - SSD's OSDs should be at-least 40% high >> >>> as compared with HDD's OSD bench. >> >>> >> >>> Did I miss anything here? Any hint is appreciated. >> >>> >> >>> Thanks >> >>> Swami >> >>> ________________________________ >> >>> >> >>> ceph-users mailing list >> >>> ceph-users@xxxxxxxxxxxxxx >> >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >> >> >> >> >> _______________________________________________ >> >> ceph-users mailing list >> >> ceph-users@xxxxxxxxxxxxxx >> >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >> >> _______________________________________________ >> ceph-users mailing list >> ceph-users@xxxxxxxxxxxxxx >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> > > > -- > Christian Balzer Network/Systems Engineer > chibi@xxxxxxx Rakuten Communications _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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