Re: after using pg_resetxlog, db lost

=?iso-8859-1?q?zhicheng=20wang?= <wang_zc(at)yahoo(dot)co(dot)uk> writes:
> in case it is useful to any one. the db server uses
> san to store the data. the update is only to the bios
> of the fibre card. if this is wrong, many other files
> should also go wrong, which is not the case.

What you should be looking at is files that were written just before
the shutdown. AFAICS the symptoms you've reported can only be explained
by assuming that the disk failed to record quite a number of writes that
were issued by Postgres just before shutdown, and it did not respect the
write/fsync order in deciding which writes it did record. This is
unfortunately fairly common behavior in IDE disks with write caching
enabled...

BTW, you never answered my question about how much data the installation
had (ie, whether it could still really be using xlog segment 0).

regards, tom lane