Database Filesystem? (Was Tracker in Edgy?)

Jamie McCracken jamiemcc at blueyonder.co.uk
Sun Jul 2 18:01:14 BST 2006


Ulrik Mikaelsson wrote:

> By the way, how well does tracker deal with large files such as
> DVD-images, and seeking?

Tracker is designed more for objects with properties like emails, 
bookmarks etc rather than storing blobs of files (there really is no 
benefit in storing them in the DB over the filesystem)


> Regarding DB-corruption I think I must agree with John a bit. I too
> find the risk of having a sudden loss of power during a
> file-relocation FS truncating my database in half, probably completely
> erasing all my Music Collection, Photos and everything I consider
> valuable in my computer, gone in the blink of an eye.

Agian this is a total non-issue with Ext3.

EXT3 offer full data journalling such that after a power failure, the 
filesystem structure *and* the file data is guaranteed to be intact. 
This is the safest available and you should never get any corruption 
with this.

EXT3 however by default uses the "ordered" mode. It is basically 
metadata journalling but adds a constraint that the writes to disk will 
be ordered in such a way that it the data is also guaranteed to be 
intact as well as the filesystem structure. It may not be the *latest* 
data that the app was told was written to disk but it is guaranteed not 
to be garbage. IE it may be the data that was there before the last write.

So for the final time - talk of databases like Tracker corrupting on 
Ext3 due to power loss is pretty much FUD (unless anyone can show 
otherwise of course).

-- 
Mr Jamie McCracken
http://jamiemcc.livejournal.com/




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