On Tue, 21 Nov 2017 10:00:28 +1100 Nigel Williams wrote: > On 20 November 2017 at 23:36, Christian Balzer <chibi@xxxxxxx> wrote: > > On Mon, 20 Nov 2017 14:02:30 +0200 Rudi Ahlers wrote: > >> The SATA drives are ST8000NM0055-1RM112 > >> > > Note that these (while fast) have an internal flash cache, limiting them to > > something like 0.2 DWPD. > > Probably not an issue with the WAL/DB on the Intels, but something to keep > > in mind. > > I had forgotten about the flash-cache hybrid drives. Seagate calls > them SSHD (Solid State Hard Drives) and as Christian highlights they > have several GB of SSD as an on-board cache. I looked at the > specifications for the ST8000NM0055 but I cannot see them listed as > SSHD, rather they seem like the usual Seagate Enterprise hard-drive. > > https://www.seagate.com/www-content/product-content/enterprise-hdd-fam/enterprise-capacity-3-5-hdd/constellation-es-4/en-us/docs/ent-capacity-3-5-hdd-8tb-ds1863-2-1510us.pdf > > Is there something in the specifications that gives them away as SSHD? > The 550TB endurance per year for an 8TB drive and the claim of 30% faster IOPS would be a dead giveaway, one thinks. Christian -- 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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