Re: Corrupted/unreadable journal: reiser vs. ext3

[Hans Reiser <reiser@namesys.com>]

I have to tell you that if you aren't willing to run fsck for reiserfs 
in response to disk corruption, but you are willing to switch to a 
filesystem (ext2) that runs fsck at every boot, I don't have a lot of 
sympathy.  Vitaly can comment more.

Hans

Dirk Schenkewitz wrote:

>Hi Guys,
>
>Recently I read about ReiserFS V4, taking that as a reason to take
>a look at ReiserFS again. But I'm not sure if it's worth to switch
>from ext3/ext2 to reiser. Because:
>
>More than a year ago, I made up one reiser-partition for playing
>around. Well, first there seemed to be nothing special about it.
>Then, one day, it suddenly couldn't read its journal anymore,
>which prevented the system from booting. (about 2 weeks later I
>discovered why: a bad power supply had caused physical damage to
>that area of the hard disk) For some reason I don't recall anymore,
>I couldn't find a reiserfsck or such. I found no way to get around
>the case of a corrupted/unreadable journal.
>
>Luckily, the partition was nearly empty, so I put on an ext3 system
>on that partition. That went fine for just a few days, than the bad
>disk area (which now held the ext3-journal) decided to strike again.
>But guess what happened:
>While booting the next time, the ext3 code discovered that the jour-
>nal was unreadable (watching that, I thought "oh shit, not again" -
>for less than a second), put out a short message stating that and 
>that it will continue as ext2. No painfull attempts to recover the
>journal - it just dropped it and continued, taking only a few seconds 
>for that.
>No data was lost! I sat there for some time, staring at the screen,
>hardly believing it.
>
>After that, I removed reiser-support from the kernels I used and
>since then I only used ext3. If I lost some data since then, it was
>only because I accidentally deleted it - there seems to be no way
>to recover anything from ext3 (unlike ext2).
>
>Because I have large amounts of data, reliability and solidness of
>a filesystem are the most important things to me, then comes space-
>efficiency, then speed. Sometimes some of my filesystems get 100%
>full, having only some kilobytes left (of, say, 8Gig) until I clean
>up. That's my personal situation & experiences.
>
>Now my questions:
>>From reading the mails from this list, I suspect that a ReiserFS:
> - will sport poor performance (whatever that means, in terms of 
>   absolute speed) if it gets more than 96% full. (*1*)
> - will fall far behind ext3 when it comes to reliability, robust-
>   ness and crash recovery (at least when fsck is involved), 
> - and will have even more trouble (which may lead to complete fai-
>   lure) if the journal cannot be accessed.
>Is any of this still true?
>
>(*1*): What if the filesystem contains rather large files, like
>       CD-images, MP3s and such, filling it up completely ? Will
>       it still slow down?
>
>>From what I wrote, you may think that I have some prejudice against
>ReiserFS. That's true, I have, because I had a bad experience with
>it. Anyway, if you (the developers and/or other people reading here)
>can say that nowadays ReiserFS is better than ext3, even under my
>personal harsh circumstances, I will give it another try. And now,
>feel free to flame me. :-)
>
>happy coding
>	dirk
>  
>


-- 
Hans