Here's some counter-evidence to the proposition that it's not pretty common for an entire cluster to go down because of a power failure. Every data center class hardware storage server product I know of has dual power input and is also designed to tolerate losing power on both at once. If that happens, they don't lose data and when the power comes back, they come back up all by themselves and start serving storage again. This design usually involves an expensive battery and maintenance procedure to make sure the battery gets replaced before it wears out (the battery is to keep the system up long enough to flush write buffers when the power fails), so users must think total power loss is a serious enough threat to pay for that. I may need to modify the above, though, now that I know how Ceph works, because I've seen storage server products that use Ceph inside. However, I'll bet the people who buy those are not aware that it's designed never to go down and if something breaks while the system is coming up, a repair action may be necessary before data is accessible again. -- Bryan Henderson San Jose, California _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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