On Tue, 28 Oct 2014 10:33:55 +0100 Mariusz Gronczewski wrote: > On Tue, 28 Oct 2014 11:32:34 +0900, Christian Balzer <chibi@xxxxxxx> > wrote: > > > On Mon, 27 Oct 2014 19:30:23 +0400 Mike wrote: > > > The fact that they make you buy the complete system with IT mode > > controllers also means that if you would want to do something like > > RAID6, you'd be forced to do it in software. > > If you are using cheap consumer drives, you definitely DO want to use > IT mode controller (and software RAID if needed), non-RAID-designed > drives perform very poorly behind hardware level abstraction. We had > LSI SAS 2208 (no IT mode flash avaliable) and it just turned disks off, > had problems with disk timeout (disks were shitty segates *DM001, no > TLER) so it dropped whole drive from raid. And using MegaCli for > everything is not exactly ergonomic. > Well, he wasn't telling us exactly which HDDs he was going to use. There are some cheap drives (HGST and certain Toshiba modesl comes to mind) that behave rather well. But I totally agree on the Seagate DM001 drives, they are the reason we no longer consider buying Seagate for at least 1-2 drive generations. > But yeah, 72 drives in 4U only makes sense if you use it for bulk > storage > That was really my point, 72 OSDs will wear out any and all dual CPU combination there is, without cycles to spare for a software RAID6. Christian -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Fusion Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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