Re: Disk Failure Scenarios

> > -Disk 2: If the transaction log dies, all changes since the last
> > checkpoint are lost, right? Again, if I set up an empty pg_xlog
> > directory somewhere else, the DB should run just fine, right?
>
> No, because there's no way to know what state the data pages are in.
> Data may have made it to disk, may not have, partial page write, etc...

As far as I understand it, data is only written to the WAL except when the
WAL is checkpointing, right? So if your WAL disk crashes and you aren't int
the middle of a checkpoint, there is a chance that you would just lose data
since the last checkpoint. Am I missing something?

Now the real question is: why are you trying to run without raid?

I have a single, very fast disk lying around, and I was just wondering what
parts of the DB I could "safely" put on it. I was thinking either the WAL
or and index. I have essentially 15 10K drives and 1 15K drive, and don't
quite know what to do with it.

-Mike