>> I am currently installing some backup servers with 6x3TB drives in them. I played with RAID-10 but I was not >> impressed at all with how it performs during a recovery. >> >> Anyway, I thought what if instead of RAID-10 I use ceph? All 6 disks will be local, so I could simply create >> 6 local OSDs + a monitor, right? Is there anything I need to watch out for in such configuration? > You can do that. Although it's nice to play with and everything, I > wouldn't recommend doing it. It will give you more pain than pleasure. Any specific reason? I just got it up and running, an after simulating some failures, I like it much better than mdraid. Again, this only applies to large arrays (6x3TB in my case). I would not use ceph to replace a RAID-1 array of course, but it looks like a good idea to replace a large RAID10 array with a local ceph installation. The only thing I do not enjoy about ceph is performance. Probably need to do more tweaking, but so far numbers are not very impressive. I have two exactly same servers running same OS, kernel, etc. Each server has 6x 3TB drives (same model and firmware #). Server 1 runs ceph (2 replicas) Server 2 runs mdraid (raid-10) I ran some very basic benchmarks on both servers: dd if=/dev/zero of=/storage/test.bin bs=1M count=100000 Ceph: 113 MB/s mdraid: 467 MB/s dd if=/storage/test.bin of=/dev/null bs=1M Ceph: 114 MB/s mdraid: 550 MB/s As you can see, mdraid is by far faster than ceph. It could be "by design", or perhaps I am not doing it right. Even despite such difference in speed, I would still go with ceph because *I think* it is more reliable. Dmitry _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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