Re: benefits of journaling for soft RAID ?

[Stephen C. Tweedie]

Hi,

On Thu, 11 Feb 1999 09:00:20 +0100, Benno Senoner <[EMAIL PROTECTED]>
said:

> can someone please explain what journaling precisely does, (is this
> a sort of mechanism, which leaves the filesystem in a consistent
> status, even in case of disk write interruption, due of power loss
> or other causes ?)

Exactly.  It keeps a record of in-progress filesystem operations so
that entire complex operations, such as renames, always complete
atomically even if you reboot half-way through.  It eliminates the
need for an fsck at reboot.

> and the advantages / disadvantages ( makes filesystem slower ?),

It _should_ make it faster, for most access patterns.  It will make
"mount -o sync" operation (for things like NFS servers) *MUCH* faster,
especially if you use a separate disk for the journal.

--Stephen