Mailinglist Archive: opensuse (4547 mails)

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RE: Fw: [SLE] ReiserFS problem?
  • From: "Carlos E. R." <robin1.listas@xxxxxxxxxx>
  • Date: Sat, 1 May 2004 02:24:19 +0200 (CEST)
  • Message-id: <Pine.LNX.4.53.0405010151580.3490@xxxxxxxxxxxxxxxx>

The Friday 2004-04-30 at 09:38 -0500, McAllister, Andrew wrote:

> My understanding of ReiserFS is that by DEFAULT only the metadata is
> journaled. See http://www.namesys.com/v4/v4.html#crashes_handl.
>
> That is to say, when a file is written, the data that goes into the file
> is NOT journaled, but the data about the file IS journaled. Thus, when
> your power goes out, the file system should be OK (or easily fixed), but
> the files themselves may contain corrupt data. Seems counter intuitive,
> but the goal of Reiserfs is limit the time it takes to fsck after a
> crash. To protect data you need to protect the machine from adverse
> events.

That's correct.

However, the original poster wrote:

>> do all that stuff. The first time it happened I recovered
>> and it all worked. Today when it happened it wiped out my
>> /home partition and everything was lost. Mostly.

That shouldn't happen, he lost a partition.


> I believe if you want to journal data and metadata, then you'll have to
> modify the ReiserFS default behavior (I presume there is a man page on
> Ext3 has similar configurations though I don't know the default behavior
> of ext3 (rtm).

I think it is not possible with reiserfs, but it is easy with ext3 - but I
don't remember how... ah, yes, man mount:

Mount options for ext3
...
data=journal / data=ordered / data=writeback
...
journal
All data is committed into the journal prior to
being written into the main file system.
...
writeback
Data ordering is not preserved - data may
be written into the main file system after its
metadata has been committed to the journal.
This is rumoured to be the highest-throughput
option. It guarantees internal file system
integrity, however it can allow old data to
appear in files after a crash and journal recovery.


> In all honesty though, you need a UPS. No matter what file system you
> have power outages will inevitably cause some sort of data corruption.

Of course!

--
Cheers,
Carlos Robinson


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