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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