On Thu, Sep 30, 2010 at 05:19, Stephan Wiesand <stephan.wies...@desy.de> wrote: ...
> Anyway, the next best option if ZFS is not available is to run parity checks > on all your arrays regularly. Perhaps it is the best one can do, but be aware that a (rare, but real) failure mode of disks is that they return the contents of a different block than asked. No amount of background scrubbing fixes that unless the failures are solid (and they are usually not). That does not even include the issue that most disk controller data paths (and cache memories) are not even parity checked, and bit flipping can happen there too. NetApp recognized this and dealt with it with the WAFL file system years ago. They actually wrote a checksum for the block and the block id onto disk and checked when they read a block back. Getting back the data your wrote is a hard problem. ZFS presumes that everything downstream of it will (eventually) fail. There is overhead there, but it does solve a set of problems that other solutions do not. (And the highly paranoid presume ZFS will fail, so take different precautions). As Jeff stated, if you really care about your data, you need ZFS. Gary _______________________________________________ OpenAFS-info mailing list OpenAFS-info@openafs.org https://lists.openafs.org/mailman/listinfo/openafs-info