On Thu, 10 Nov 2011, Tomas Forsman wrote:


Loss of data as seen by the client can definitely occur.

When a client writes something, and something else ends up on disk - I
call that corruption. Doesn't matter whose fault it is and technical
details, the wrong data was stored despite the client being careful when
writing.

Unlike many filesystems, zfs does not prioritize sync data over async data when it comes to finally writing the data to main store. Sync data is written to an intent log, which is replayed (as required) when the server reboots. Disabling sync disables this intent log and so data should be consistently set back in time if sync is disabled and the server does an unclean reboot. From this standpoint, the filesystem does not become "corrupted". Regardless, data formats like databases could become internally corrupted due to the data written in a zfs transaction group not being representative of a coherent database transaction.

Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
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