Foreign keys / Transactions in MySQL.. WTF?

Paul LeoNerd Evans leonerd at leonerd.org.uk
Wed Aug 1 23:59:58 BST 2007


On Wed, 1 Aug 2007 00:40:24 -0500
"Jonathan T. Rockway" <jon at jrock.us> wrote:

> Does MySQL guarantee that the filesystem is in a legal state at all
> times?  If not, a filesystem-level backup is just going to give you
> garbage.

I would hope so, or else how's it going to cope if the whole kernel
suddenly crashes, or power fails with no UPS, or any of those sorts of
things? The state of the files on-disk has to be consistent at all times,
at least as far as MySQL itself can arrange.

I know there's such things as block-level write caching and deferred
block flushing the kernel, but things like an LVM layer will cope with
that - an LVM snapshot should be clean.

-- 
Paul "LeoNerd" Evans

leonerd at leonerd.org.uk
ICQ# 4135350       |  Registered Linux# 179460
http://www.leonerd.org.uk/


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