On 16/06/11 3:09 AM, Simon Walter wrote: > On 06/16/2011 09:09 AM, Erik Trimble wrote: >> We had a similar discussion a couple of years ago here, under the >> title "A Versioning FS". Look through the archives for the full >> discussion. >> >> The jist is that application-level versioning (and consistency) is >> completely orthogonal to filesystem-level snapshots and consistency. >> IMHO, they should never be mixed together - there are way too many >> corner cases and application-specific memes for a filesystem to ever >> fully handle file-level versioning and *application*-level data >> consistency. Don't mistake one for the other, and, don't try to *use* >> one for the other. They're completely different creatures. >> > > I guess that is true of the current FSs available. Though it would be > nice to essentially have a versioning FS in the kernel rather than an > application in userspace. But I regress. I'll use SVN and webdav.
To use Svn correctly here, you have to resolve the same issue. Svn has a global revision, just as a snapshot is a state for an *entire* filesystem. You don't seem to have taken that into sufficient account when talking about ZFS; it doesn't align with your goal of consistency from the point of view of a *single document*. You'll only be able to make a useful snapshot in Svn at moments when *all* documents in the repository are in a consistent state (I'm assuming this is a multi-user system). That's a much stronger guarantee than you probably 'require' for your purpose, so it makes me wonder whether what you really want is a document database (or, to be honest, an ordinary filesystem; you can "snapshot" single documents in an ordinary filesystem using say hard links) where the state of each session/document is *independent*. You can see that the latter model is much more like Google Docs, not to mention simpler; and the "snapshot" model is not like it at all. --Toby > > Thanks for the advice everyone. > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
