Re: HEADS UP: New ZFS in the tree.

From: Peter Schuller <peter.schuller_at_infidyne.com>
Date: Sun, 7 Dec 2008 12:35:10 +0100
> While you are talking about it: Does anyone know if the fsync blocks
> until the data is really stable on the device or if it simply returns
> when ZIL is disabled?
> 
> In my understanding the topmost block would need to be written for the
> "commit" to be on disk.

My understanding is that disabling the ZIL *will* break the semantics
of fsync().

The claim of "always consistent on disk" is not violated and is still
maintained, since consistency refers to ZFS' internal consistency.

The tuning guide someone posts a link to later in this thread has
specific claims about this IIRC; such as NFS breaking (because
fsync-on-close semantics mandated by NFS, among other things, will not
be honored).

-- 
/ Peter Schuller

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Received on Sun Dec 07 2008 - 10:35:12 UTC

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