Le 23/11/2015 18:17, Jan Schermer a écrit : > SW-RAID doesn't help with bit-rot if that's what you're afraid of. > If you are afraid bit-rot you need to use a fully checksumming filesystem like ZFS. > Ceph doesn't help there either when using replicas - not sure how strong error detection+correction is in EC-type pools. > > The only thing I can suggest (apart from using ZFS) is getting drives that have a higher BER rating so bit-rot isn't as likely to occur. We use BTRFS for this reason (we had to circumvent some performance problems with it to do so). Drives aren't the only possible sources of bit-rot unfortunately. We had HP Raid controllers of Gen8 servers slowly but consistently corrupting data after a datacenter-wide power failure which damaged some equipment. For reference the power failure itself was correctly handled but when the electrical facility resolved the problem it sent a power surge which destroyed parts of the power management system and apparently some Raid controllers didn't like the surge either: BTRFS checksum errors started to pop with an abnormal rate (we have enough data writes to statistically get one or two of them each year with consumer-level SATA drives but it rose to one per day). Lionel _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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