Re: disaster recovery

"Rick Gigger" <rick@alpinenetworking.com> writes:

>> This is only a problem for ext2.  Ext3, Reiser, XFS, JFS are all fine,
>> though you get better performance from them by mounting them
>> 'writeback'.
>
> What does 'writeback' do exactly?

AFAIK 'writeback' only applies to ext3.  The 'data=writeback' setting
journals metadata but not data, so it's faster but may lose file
contents in case of a crash.  For Postgres, which calls fsync() on the
WAL, this is not an issue since when fsync() returns the file contents
are commited to disk.

AFAIK XFS and JFS are always in 'writeback' mode; I'm not sure about
Reiser.

-Doug