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? _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com