The official ceph documentation recommendations for a db partition for a 4TB bluestore osd would be 160GB each.
Samsung Evo Pro is not an Enterprise class SSD. A quick search of the ML will allow which SSDs people are using. As was already suggested, the better option is an HBA as opposed to a raid controller. If you are set on your controllers, write-back is fine as long as you have BBU. Otherwise you should be using write-through. On Thu, Sep 6, 2018, 8:54 AM Muhammad Junaid <junaid.fsd...@gmail.com> wrote: > Thanks. Can you please clarify, if we use any other enterprise class SSD > for journal, should we enable write-back caching available on raid > controller for journal device or connect it as write through. Regards. > > On Thu, Sep 6, 2018 at 4:50 PM Marc Roos <m.r...@f1-outsourcing.eu> wrote: > >> >> >> >> Do not use Samsung 850 PRO for journal >> Just use LSI logic HBA (eg. SAS2308) >> >> >> -----Original Message----- >> From: Muhammad Junaid [mailto:junaid.fsd...@gmail.com] >> Sent: donderdag 6 september 2018 13:18 >> To: ceph-users@lists.ceph.com >> Subject: [ceph-users] help needed >> >> Hi there >> >> Hope, every one will be fine. I need an urgent help in ceph cluster >> design. We are planning 3 OSD node cluster in the beginning. Details are >> as under: >> >> Servers: 3 * DELL R720xd >> OS Drives: 2 2.5" SSD >> OSD Drives: 10 3.5" SAS 7200rpm 3/4 TB >> Journal Drives: 2 SSD's Samsung 850 PRO 256GB each Raid controller: PERC >> H710 (512MB Cache) OSD Drives: On raid0 mode Journal Drives: JBOD Mode >> Rocks db: On same Journal drives >> >> My question is: is this setup good for a start? And critical question >> is: should we enable write back caching on controller for Journal >> drives? Pls suggest. Thanks in advance. Regards. >> >> Muhammad Junaid >> >> >> >> _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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