I like the suggestion about the Intel SSDs, but doesn't Dell have a firmware restriction about what drives can go on their controllers? Their cheapest SSD for the 515 $1000+. In a previous conversation, you'd mentioned putting an LSI 9260 in an R515. This would allow someone to get around this restriction correct?
Dave Spano ----- Original Message ----- From: "Mark Nelson" <mark.nel...@inktank.com> To: "Barry O'Rourke" <Barry.O'rou...@ed.ac.uk> Cc: ceph-users@lists.ceph.com Sent: Tuesday, May 7, 2013 5:02:42 PM Subject: Re: [ceph-users] Dell R515 performance and specification question On 05/07/2013 03:36 PM, Barry O'Rourke wrote: > Hi, > >> With so few disks and the inability to do 10GbE, you may want to >> consider doing something like 5-6 R410s or R415s and just using the >> on-board controller with a couple of SATA disks and 1 SSD for the >> journal. That should give you better aggregate performance since in >> your case you can't use 10GbE. It will also spread your OSDs across >> more hosts for better redundancy and may not cost that much more per GB >> since you won't need to use the H700 card if you are using an SSD for >> journals. It's not as dense as R515s or R720XDs can be when fully >> loaded, but for small clusters with few disks I think it's a good >> trade-off to get the added redundancy and avoid expander/controller >> complications. > > I hadn't considered lowering the specification and increasing the number > of hosts, that seems like a really viable option and not too much more > expensive. When you say the on-board controller do you mean the onboard > SATA or the H310 controller? Good question on the controller. I suspect the on-board will be good enough for 1GbE or even bonded 1GbE throughput levels. I've also heard some mixed things about the H310 but haven't gotten to test one myself. What I've seen in the past is that if you are only using spinning disks, a controller with on-board cache will help performance quite a bit. If you have an SSD drive for journals, you can get away with much cheaper sata/SAS controllers. You mentioned earlier that the Dell SSDs were quite expensive. Have you considered something like an Intel DC S3700? If you can't get one through Dell, you might consider just doing 3 disks from Dell and adding one yourself (you could put OS and journals on it, and use the 3 spinning disks for OSDs). This does have the effect though of making the SSD a single point of failure (which is why it's good to use the enterprise grade drive here I think). Mark > > Thanks, > > Barry > > > _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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