On Wed, 7 Jan 2004 10:04:26 -0500 JoeHill <[EMAIL PROTECTED]> wrote: > Unless I am minsunderstanding you, and fsck is used *in the recovery > of the journal*?
True for ext3, it is and should never be used for ReisferFS or XFS
>
> I am also assuming that the 'file system integrity check' offered
> during the boot process is the same thing as 'fsck'.
No.
Fsck would be invoked If anomalies were found during the 'file system
integrity check'
Disk transactions are written sequentially to an area of disk called
journal or log before being written to their final locations within the
filesystem. Implementations vary in terms of what data is written to the
log. Some implementations write only the filesystem metadata, while
others record all writes to the journal.
Now, if a crash happens before the journal entry is committed, then the
original data is still on the disk and you lost only your new changes.
If the crash happens during the actual disk update (i.e. after the
journal entry was committed), the journal entry shows what was supposed
to have happened. So when the system reboots, it can simply replay the
journal entries and complete the update that was interrupted.
In either case, you have valid data and not a trashed partition. And
since the recovery time associated with this log-based approach is much
shorter, the system is on line in few seconds.
Hardware and software errors that corrupt random blocks in the
filesystem are not generally recoverable with the transaction log and
necessitate the usage of fsck.
After a crash or hard reset is when these hardware and software errors
are most likely to manifest themselves.
Choosing to skip fsck will allow these errors to not only remain but
also allow them to propagate and fester.
This may appear to have no effect on system performance or behaviour
but as time progresses, depending upon the root cause of the error, the
system behaviour may and can become erratic leading to even
non-recoverability and a forced reinstall.
Charles
--
Instead of loving your enemies, treat your friends a little better.
-- Edgar W. Howe
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Mandrake Linux 10.0 on PurpleDragon
Kernel-2.6.0-1mdkenterprise
http://www.eslrahc.com
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