Filesysstems

Heyho!

On Friday 05 March 2010 20.18:46 Greg Smith wrote:
> The short version is that ext3 combined with regular hard drives has
> never been safe for database use by default, [...]
> The change in ext4 [...] eliminating the source for that cheat.

Tangentially related: how is the behaviour [1] of pg when the db is located
on an extent based cow filesysstem like btrfs? I'm not too sure about the
internals, but my understanding is that the mechanism is a bit similar to
what pg does with its mvcc: new content is written into empty space and then
later pointers are updated to point to the new content.

[1] I'd expect that there are no issues with reliability, assuming the fs is
bug-free. I'm more worried about performance. Wouldn't the table files get
fragmented more and more with updates?

cheers
-- vbi

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