Hi Peter, Thanks a lot for your consideration in terms of storage consumption.
The other question is considering having one OSDs vs 8 OSDs... 8 OSDs will consume more CPU than 1 OSD (RAID5) ? As I want to share compute and osd in the same box, resources consumed by OSD can be a handicap. Thanks a lot. 2017-11-13 12:59 GMT+01:00 Peter Maloney <peter.malo...@brockmann-consult.de >: > Once you've replaced an OSD, you'll see it is quite simple... doing it for > a few is not much more work (you've scripted it, right?). I don't see RAID > as giving any benefit here at all. It's not tricky...it's perfectly normal > operation. Just get used to ceph, and it'll be as normal as replacing a > RAID disk. And for performance degradation, maybe it could be better on > either... or better on ceph if you don't mind setting the rate to the > lowest... but when the QoS functionality is ready, probably ceph will be > much better. Also RAID will cost you more for hardware. > > And raid5 is really bad for IOPS. And ceph already replicates, so you will > have 2 layers of redundancy... and ceph does it cluster wide, not just one > machine. Using ceph with replication is like all your free space as hot > spares... you could lose 2 disks on all your machines, and it can still run > (assuming it had time to recover in between, and enough space). And you > don't want min_size=1, and if you have 2 layers of redundancy, you'll be > tempted to do that probably. > > But for some workloads, like RBD, ceph doesn't balance out the workload > very evenly for a specific client, only many clients at once... raid might > help solve that, but I don't see it as worth it. > > I would just software RAID1 the OS and mons, and mds, not the OSDs. > > > On 11/13/17 12:26, Oscar Segarra wrote: > > Hi, > > I'm designing my infraestructure. I want to provide 8TB (8 disks x 1TB > each) of data per host just for Microsoft Windows 10 VDI. In each host I > will have storage (ceph osd) and compute (on kvm). > > I'd like to hear your opinion about theese two configurations: > > 1.- RAID5 with 8 disks (I will have 7TB but for me it is enough) + 1 OSD > daemon > 2.- 8 OSD daemons > > I'm a little bit worried that 8 osd daemons can affect performance because > all jobs running and scrubbing. > > Another question is the procedure of a replacement of a failed disk. In > case of a big RAID, replacement is direct. In case of many OSDs, the > procedure is a little bit tricky. > > http://ceph.com/geen-categorie/admin-guide-replacing-a-failed-disk-in-a- > ceph-cluster/ > > What is your advice? > > Thanks a lot everybody in advance... > > > _______________________________________________ > ceph-users mailing > listceph-us...@lists.ceph.comhttp://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > -- > > -------------------------------------------- > Peter Maloney > Brockmann Consult > Max-Planck-Str. 2 > 21502 Geesthacht > Germany > Tel: +49 4152 889 300 <+49%204152%20889300> > Fax: +49 4152 889 333 <+49%204152%20889333> > E-mail: peter.malo...@brockmann-consult.de > Internet: http://www.brockmann-consult.de > -------------------------------------------- > >
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