> Op 13 aug. 2016 om 03:19 heeft Bill Sharer <bsha...@sharerland.com> het > volgende geschreven: > > If all the system disk does is handle the o/s (ie osd journals are on > dedicated or osd drives as well), no problem. Just rebuild the system and > copy the ceph.conf back in when you re-install ceph. Keep a spare copy of > your original fstab to keep your osd filesystem mounts straight. >
With systems deployed with ceph-disk/ceph-deploy you no longer need a fstab. Udev handles it. > Just keep in mind that you are down 11 osds while that system drive gets > rebuilt though. It's safer to do 10 osds and then have a mirror set for the > system disk. > In the years that I run Ceph I rarely see OS disks fail. Why bother? Ceph is designed for failure. I would not sacrifice a OSD slot for a OS disk. Also, let's say a additional OS disk is €100. If you put that disk in 20 machines that's €2.000. For that money you can even buy a additional chassis. No, I would run on a single OS disk. It fails? Let it fail. Re-install and you're good again. Ceph makes sure the data is safe. Wido > Bill Sharer > > >> On 08/12/2016 03:33 PM, Ronny Aasen wrote: >>> On 12.08.2016 13:41, Félix Barbeira wrote: >>> Hi, >>> >>> I'm planning to make a ceph cluster but I have a serious doubt. At this >>> moment we have ~10 servers DELL R730xd with 12x4TB SATA disks. The official >>> ceph docs says: >>> >>> "We recommend using a dedicated drive for the operating system and >>> software, and one drive for each Ceph OSD Daemon you run on the host." >>> >>> I could use for example 1 disk for the OS and 11 for OSD data. In the >>> operating system I would run 11 daemons to control the OSDs. But...what >>> happen to the cluster if the disk with the OS fails?? maybe the cluster >>> thinks that 11 OSD failed and try to replicate all that data over the >>> cluster...that sounds no good. >>> >>> Should I use 2 disks for the OS making a RAID1? in this case I'm "wasting" >>> 8TB only for ~10GB that the OS needs. >>> >>> In all the docs that i've been reading says ceph has no unique single point >>> of failure, so I think that this scenario must have a optimal solution, >>> maybe somebody could help me. >>> >>> Thanks in advance. >>> >>> -- >>> Félix Barbeira. >>> >> if you do not have dedicated slots on the back for OS disks, then i would >> recomend using SATADOM flash modules directly into a SATA port internal in >> the machine. Saves you 2 slots for osd's and they are quite reliable. you >> could even use 2 sd cards if your machine have the internal SD slot >> >> http://www.dell.com/downloads/global/products/pedge/en/poweredge-idsdm-whitepaper-en.pdf >> >> kind regards >> Ronny Aasen >> >> >> _______________________________________________ >> ceph-users mailing list >> ceph-users@lists.ceph.com >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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