"Stephen C. Tweedie" wrote:
> 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.
With today large disks 10+ GB avoiding the long fsck at boot time is a
feature which
is strongly needed. ( in this case NT has the advantage over Linux
because it
has some sort of journaling, therefore it boots relatively fast even on
an unclean shutdown).
I plan to make some multimedia workstations which plays big audio/video
files,
from a soft-RAID array.
but actually the customer , in the worst case (in case of an fsck) must
turn on the power of the machine 30-60min (for a 90% full 70GB array)
before actual usage.
In my case the machines can not remain powered up all the time, because
the machines will be used for presentations at different locations.
Stephen: do you have an estimate time for wich journaling will be ready
for use,
even as an alpha-patch ?
do you think that at end of 1999 there is something available ?
>
>
> > 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.
hmm, .. I think that using the journaling filesystem over a RAID5 array,
since RAID5 balances the loadover all the disks,
even using the "same" disk (the raid array) for journaling,
would not degrade performance ?
please correct me if I am wrong.
regards,
Benno.
>
>
> --Stephen
