reiserFS?

reiserFS?

[ivo welch]

dear linux geeks:  may I ask why the "new" (many years old) reiser
filesystem is not making it into the kernel?  it does seem to have
some advantages, if nothing else at least over the old reiser v3.

sincerely,  /ivo welch

(please cc me personally. I am not a linux geek accdg to the lkml faq,
but just an end user.)

Re: reiserFS?

[Matthias Andree]

On Sun, 16 Jul 2006, ivo welch wrote:

> dear linux geeks:  may I ask why the "new" (many years old) reiser
> filesystem is not making it into the kernel?  it does seem to have
> some advantages, if nothing else at least over the old reiser v3.

Why would anyone want ReiserFS in the kernel that is discontinued by its
developers when it's just started to become stabile and useful, with
bugs (hashing) remaining, as happened with 3.6? Who is going to make
guarantees this won't happen again with reiser4?

Besides that, there had been technical discrepancies that prevented
reiser4 inclusion into the baseline kernel when it was suggested, search
the archives for details.

There's ext3, you can set the dir_index option (either for mke2fs, or
afterwards with tune2fs, then unmount and run e2fsck -fD) and you're set.

-- 
Matthias Andree

Re: reiserFS?

[Lexington Luthor]

Matthias Andree wrote:
> Why would anyone want ReiserFS in the kernel that is discontinued by its
> developers when it's just started to become stabile and useful, with
> bugs (hashing) remaining, as happened with 3.6? Who is going to make
> guarantees this won't happen again with reiser4?

I looked at the reiser4 patch, and it does very little outside of the 
fs/reiser4 directory. If it is no longer supported by namesys, why can't 
it just be removed from the kernel like all the other bits that are 
obsoleted?

I am just saddened that kernel decisions are motivated by politics and a 
personal dislike of Hans Reiser rather than technical merit. :(

> There's ext3, you can set the dir_index option (either for mke2fs, or
> afterwards with tune2fs, then unmount and run e2fsck -fD) and you're set.

I am not arguing for the inclusion of reiser4 in the kernel, but you 
should know it has its uses. There are very many things that reiser4 can 
do that will make ext3 blow up. It simply the best filesystem for many 
kinds of usage patterns.

Regards,
LL

Re: reiserFS?

[grundig]

El Sun, 16 Jul 2006 16:29:24 +0100,
Lexington Luthor <Lexington.Luthor@gmail.com> escribió:

> I am just saddened that kernel decisions are motivated by politics and a 
> personal dislike of Hans Reiser rather than technical merit. :(

You (and every reiser4 fan that FUDs against linux developers just because
he can't understand why reiser4 still is not in) are seriously missing the
point.

Nobody is oppossing that reiser4 gets into the main linux tree. Let me
remember you that Linux has already merged quite a lot of filesystems,
including a lot of them that don't even matter in the real world (BeFS,
minix, ADFS, AFFS, EFS, VXFS, qnx4fs, sysvfs, ncpfs, codafs. Let me
also remember you that we have had other relevant filesystems for year
(reiser3, XFS, JFS), and everybody is ok with them, nobody is planning
to kill anyone.

With this short panoramic view of Linux I find shocking that people
dares even to _suggest_ that linux don't want to include a filesystem
for "political reasons".

Just to point you how wrong you are, compare OCFS2 and GFS. Both of them
are clustering filesystems, being OCFS from Oracle and GFS from Redhat.
_Both_ filesystems have been asked to be included in the main tree. As for
today, only OCFS2 is in (since 2.6.16, after several reviews and after
fixing their code like everyone else). GFS still isn't in and seems to
need work, but you won't see to the GFS technical leader tell everybody
(like Hans has done here) that Linux politics don't allow GFS to go in.
Instead of wining, they just go back to work on their issues.

Re: reiserFS?

[Arjan van de Ven]

> With this short panoramic view of Linux I find shocking that people
> dares even to _suggest_ that linux don't want to include a filesystem
> for "political reasons".

that's just their way of doing politics; they think that by using that
sort of psychological warfare the code gets merged without review rather
than with ... and sometimes it even works unfortunately.

Re: reiserFS?

[Lexington Luthor]

grundig wrote:
> You (and every reiser4 fan that FUDs against linux developers just because
> he can't understand why reiser4 still is not in) are seriously missing the
> point.

Easy there... I am not trying to get reiser4 merged, I am just trying to 
understand why it isn't already there. I am sure I have misunderstood 
something, otherwise there would not be such a great debate about this 
issue. I just would like to know more.

> Just to point you how wrong you are, compare OCFS2 and GFS. Both of them
> are clustering filesystems, being OCFS from Oracle and GFS from Redhat.
> _Both_ filesystems have been asked to be included in the main tree. As for
> today, only OCFS2 is in (since 2.6.16, after several reviews and after
> fixing their code like everyone else). GFS still isn't in and seems to
> need work, but you won't see to the GFS technical leader tell everybody
> (like Hans has done here) that Linux politics don't allow GFS to go in.
> Instead of wining, they just go back to work on their issues.

Can you please point me to the current list of issues regarding reiser4 
which are holding back its merging? Perhaps I can help with some of them.

Thanks,
LL

Re: reiserFS?

[Matthias Andree]

On Sun, 16 Jul 2006, Lexington Luthor wrote:

> Matthias Andree wrote:
> >Why would anyone want ReiserFS in the kernel that is discontinued by its
> >developers when it's just started to become stabile and useful, with
> >bugs (hashing) remaining, as happened with 3.6? Who is going to make
> >guarantees this won't happen again with reiser4?
> 
> I looked at the reiser4 patch, and it does very little outside of the 
> fs/reiser4 directory. If it is no longer supported by namesys, why can't 
> it just be removed from the kernel like all the other bits that are 
> obsoleted?

People (including you) would scream blue murder if their file system
were going away. The same would happen if it just didn't work for them.

Somebody, however skilled they may be, just trying out a patch and
finding it works for them is certainly not sufficient reason to judge if
a product is of adequate quality. The code was reviewed, found to
contain major misdesigns, and the maintainers refused to fix those, and
that's it.

> I am just saddened that kernel decisions are motivated by politics and a 
> personal dislike of Hans Reiser rather than technical merit. :(

If you had understood my postings, it had been clear to you that there
have been technical reasons that blocked the inclusion, and there have
additionally been precedences of such misconduct, or maintainers
declaring the system stable when in fact it was years (literally) from
that.

I respect namesys for the efforts they made in getting 3.6 and the
toolchain workable, but some issues remain that some people never run
into, are showstoppers for others, and at that point where minor
polishing was due, namesys moved on to reiser4, dropping 3.6 support -
and that was a decision that made me phase out reiserfs 3.6, and I'm
certainly not looking into reiser4 until 2 years after a first major
distro (that's currently Debian, Ubuntu, Fedora, Opensuse, Mandrake)
ships it as the default root and user FS.

> >There's ext3, you can set the dir_index option (either for mke2fs, or
> >afterwards with tune2fs, then unmount and run e2fsck -fD) and you're set.
> 
> I am not arguing for the inclusion of reiser4 in the kernel, but you 
> should know it has its uses. There are very many things that reiser4 can 
> do that will make ext3 blow up. It simply the best filesystem for many 
> kinds of usage patterns.

Apparently, kernel coding standard applicability doesn't fall into the
usage patterns you're referring to. SCNR. I haven't heard the other
side, but if you're going to contribute to some project you MUST please
its maintainers - life's bad...

-- 
Matthias Andree

Re: reiserFS?

[Joseph Le-Phan]

ivo welch wrote:
> dear linux geeks:  may I ask why the "new" (many years old) reiser
> filesystem is not making it into the kernel?  it does seem to have
> some advantages, if nothing else at least over the old reiser v3.
>
> sincerely,  /ivo welch
>
> (please cc me personally. I am not a linux geek accdg to the lkml faq,
> but just an end user.)

There have been countless discussions on this matter. Please search the
archives.

-- 
Joseph Le-Phan <five0.oss ∈ gmail.com> [GPG key: 292E09A0]

Re: reiserFS?

[Xavier Roche]

> It simply the best filesystem for many kinds of usage patterns.

The most frightening too. Reiserfs might be suitable for very specific appliactions, but to use it in production machine, you need to have some guts.

My last reiserfs partition was blown up two days ago, because of a bad sector, plus a fatal oops, looping endlessly. This was the second time, and the last one, as none of my ext3 filesystems *ever* had similar problems, despite numerous other bad sector issues. Not mentionning the funny "recovery" tool, which generally finishes to trash your data.

Jul 14 23:35:29 linux kernel: hdh: dma_intr: status=0x51 { DriveReady SeekComplete Error }
Jul 14 23:35:29 linux kernel: hdh: dma_intr: error=0x40 { UncorrectableError }, LBAsect=12458384, sector=12458383
Jul 14 23:35:29 linux kernel: ide: failed opcode was: unknown
Jul 14 23:35:29 linux kernel: end_request: I/O error, dev hdh, sector 12458383
Jul 14 23:35:29 linux kernel: ------------[ cut here ]------------
Jul 14 23:35:29 linux kernel: kernel BUG at fs/reiserfs/file.c:620!
..
Jul 14 23:35:29 linux kernel:  <0>Fatal exception: panic in 5 seconds

The funny part is that 14 july is the french's fireworks day, generally launched around midnight.

Re: reiserFS?

[Christian Trefzer]

[-- Attachment #1: Type: text/plain, Size: 1397 bytes --]

On Sun, Jul 16, 2006 at 06:16:31PM +0200, Xavier Roche wrote:
> > It simply the best filesystem for many kinds of usage patterns.
> 
> The most frightening too. Reiserfs might be suitable for very specific
> appliactions, but to use it in production machine, you need to have
> some guts.
> 
> My last reiserfs partition was blown up two days ago, because of a bad
> sector, plus a fatal oops, looping endlessly. This was the second
> time, and the last one, as none of my ext3 filesystems *ever* had
> similar problems, despite numerous other bad sector issues. Not
> mentionning the funny "recovery" tool, which generally finishes to
> trash your data.

I don't quite understand. You are supposed to dd_rescue the whole block
device to a working drive and use fsck on the copy.  Whatever is lost in
the process must of course be restored from a recent backup. But, as a
friend of mine put it recently, people don't need backup, they only need
restore ; )

fsck on a faulty drive might cause even more damage - how do you know
that other areas of the device are OK? 

I also oppose the ReiserFS-v3.x design philosophy regarding faulty
storage layer, but in any case where your _live_ data is valuable and
uptime counts, you _really_should_ use a RAID of some sort.

Kind regards,
uziel

PS: Your mail was line-wrapped really bad, you might want to look into
that.

[-- Attachment #2: Type: application/pgp-signature, Size: 827 bytes --]

Re: reiserFS?

[Theodore Tso]

On Sun, Jul 16, 2006 at 06:28:31PM +0200, Christian Trefzer wrote:
> I don't quite understand. You are supposed to dd_rescue the whole block
> device to a working drive and use fsck on the copy.  Whatever is lost in
> the process must of course be restored from a recent backup. But, as a
> friend of mine put it recently, people don't need backup, they only need
> restore ; )

If the disk is known to be bad, yes, and the number of bad blocks is
growing.  On the other hand, disks can and will have a few bad blocks,
or bad writes that don't mean the disk is going bad, and a modern
filesystem should be robust enough that a single failed sector doesn't
cause the filesystem to go completely kaput.

In fact, one of the scary trends with hard drives is that size is
continuing to grow expoentially, access times linearly (more or less),
and error rates (errors per kilobytes per unit time) are remaining
more or less constant.

The fact that reiserfs uses a single B-tree to store all of its data
means that very entertaining things can happen if you lose a sector
containing a high-level node in the tree.  It's even more entertaining
if you have image files (like initrd files) in reiserfs format stored
in reiserfs, and you run the recovery program on the filesystem.....

Yes, I know that reiserfs4 is alleged to fix this problem, but as far
as I know it is still using a single unitary tree, with all of the
pitfalls that this entails.

Now, that being said, that by itself is not a reason not to decide not
to include reseirfs4 into the mainline sources.  (I might privately
get amused when system administrators use reiserfs and then report
massive data loss, but that's my own failure of chairty; I'm working
on it.)  For the technical reasons why resierfs4 hasn't been
integrated, please see the mailing list archives.

						- Ted

Re: reiserFS?

[Lexington Luthor]

Theodore Tso wrote:
> If the disk is known to be bad, yes, and the number of bad blocks is
> growing.  On the other hand, disks can and will have a few bad blocks,
> or bad writes that don't mean the disk is going bad, and a modern
> filesystem should be robust enough that a single failed sector doesn't
> cause the filesystem to go completely kaput.

I never trust a single hard drive with data that cannot be instantly 
re-generated anyway (eg squid caches). The fact that some people have 
hardware errors should not require every single fs to accommodate random 
bad-sectors. Feel free to use ext3 or other fs which handles this 
situation (and other situations) better, but reiserfs works fine on good 
hardware. It has been my root filesystem on many systems with no 
problems whatsoever, even with cheap SATA drives.

> In fact, one of the scary trends with hard drives is that size is
> continuing to grow expoentially, access times linearly (more or less),
> and error rates (errors per kilobytes per unit time) are remaining
> more or less constant.
> 
> The fact that reiserfs uses a single B-tree to store all of its data
> means that very entertaining things can happen if you lose a sector
> containing a high-level node in the tree.  It's even more entertaining
> if you have image files (like initrd files) in reiserfs format stored
> in reiserfs, and you run the recovery program on the filesystem.....
> 
> Yes, I know that reiserfs4 is alleged to fix this problem, but as far
> as I know it is still using a single unitary tree, with all of the
> pitfalls that this entails.
> 
> Now, that being said, that by itself is not a reason not to decide not
> to include reseirfs4 into the mainline sources.  (I might privately
> get amused when system administrators use reiserfs and then report
> massive data loss, but that's my own failure of chairty; I'm working
> on it.)  For the technical reasons why resierfs4 hasn't been
> integrated, please see the mailing list archives.
> 

I read the archives, and most of the problems pointed out during the 
review were fixed relatively quickly, followed by a flame war due to 
some suggesting that reiser4 should not be able to affect VFS semantics, 
and other such matters (which IMO should be outside of the scope of a 
code review). There has been no follow-up review as far as I can tell. 
The discussion quickly degenerated into a personality argument against 
Mr Reiser, with several developers taking a strong position against 
reiser4 (the exact reasons for which are not specified).

I don't quite know where reiser4 stands at the moment, given that it is 
in -mm and has been for a very long time. I also looked at the patch 
again, and it is indeed quite well isolated from the rest of the kernel 
so I don't understand why it is not being merged as an EXPERIMENTAL option.

Regardless, it is available in -mm for anyone to use, and last I 
checked, works incredibly well leaving other filesystems miles behind in 
terms of speed. I haven't tested it enough to comment on the 
reliability, but if it is as reliable as reiserfs, it is sufficient for 
me and many others who use RAID and a UPS.

Regards,
LL

Re: reiserFS?

[Theodore Tso]

On Sun, Jul 16, 2006 at 06:26:03PM +0100, Lexington Luthor wrote:
> I read the archives, and most of the problems pointed out during the 
> review were fixed relatively quickly, followed by a flame war due to 
> some suggesting that reiser4 should not be able to affect VFS semantics, 
> and other such matters (which IMO should be outside of the scope of a 
> code review). There has been no follow-up review as far as I can tell. 

As far as I know not all of the problems were fixed.  And it has been
observed that given the abuse and accusations that were directed at
the people who did decide to review it, that it would not at all
surprising if some (all?) of reviewers may have decided they had
better things to do.  Getting things merged into mainline is not a
right, and the reviewers are volunteers.....

Speaking for myself, since I don't enjoy being accused of partisanship
and being ascribed of having a desire to backstab reiserfs, I have a
personal policy to avoid reiserfs review, and recuse myself from any
votes within program committee discussions regarding Hans Reiser.
Being accused of taking unfair advantage of my volunteer activities is
something I allow myself to get into once.

						- Ted

Re: reiserFS?

[Dr. David Alan Gilbert]

It is a sad reflection that we have these regular 'fs wars'; and that
most of them are driven by peoples bad experiences with particular
filesystems.

That leads me to ask what level of testing is performed on each
filesystem - are there filesystem torture tests that are getting
run by someone (who?) on various filesystems (preferably on large
TB sized ones, preferably with simulated failures and resets)?
The discussions on Ext4 a few weeks ago made me think that the
thing I'd value more than anything else would be a damn good
test regime.

It would be much nicer if the fs wars came down to peoples
particularly good experiences with filesystems rather than people
selecting file systems based on which one has lost them data most
rarely.

Dave

P.S. For the record I use Reiser for large (>500GB) fs since 
I couldn't get Ext3 stable on one a year or so ago and xfs failed
the 'recover from hitting reset' test.   A couple of years
ago I wouldn't touch Reiser because of NFS issues, but it seems
to have grown out of that.
-- 
 -----Open up your eyes, open up your mind, open up your code -------   
/ Dr. David Alan Gilbert    | Running GNU/Linux on Alpha,68K| Happy  \ 
\ gro.gilbert @ treblig.org | MIPS,x86,ARM,SPARC,PPC & HPPA | In Hex /
 \ _________________________|_____ http://www.treblig.org   |_______/

Re: reiserFS?

[Theodore Tso]

On Sun, Jul 16, 2006 at 06:46:37PM +0100, Dr. David Alan Gilbert wrote:
> That leads me to ask what level of testing is performed on each
> filesystem - are there filesystem torture tests that are getting
> run by someone (who?) on various filesystems (preferably on large
> TB sized ones, preferably with simulated failures and resets)?
> The discussions on Ext4 a few weeks ago made me think that the
> thing I'd value more than anything else would be a damn good
> test regime.

As far as I know ext2/3 is the only filesystem with a fsck tool that
has a regression test suite.  It's always amazed me that filesystem
consistency checkers and repair tools get so little attenion by most
filesystem developers.

As far as random torture testing, Pavel has written a random test tool
that punches random errors into random blocks of a filesystem, and
that was used to uncover a couple of cases that e2fsprogs didn't
handle cleanly.  Those were reported to me, and I fixed them, and the
edge cases were encorprated into the regression test suite.

IIRC it came up in discussion a few weeks ago one LKML or
linux-fsdevel (I can't remember which), and I believe either someone
from XFS or Reiser team was going to take Pavel's torture tester and
adapt it do some robustifying of their filesystem's repair
capabilities.

Finally, the good folks at the Stanford Metacompilation group did some
very interesting work to find bugs in three common Linux filesystems:

	http://keeda.stanford.edu/~junfeng/papers/osdi04/osdi04.html

Regards,

						- Ted

Re: reiserFS?

[Matthias Andree]

Christian Trefzer schrieb am 2006-07-16:

> fsck on a faulty drive might cause even more damage - how do you know
> that other areas of the device are OK? 

All drives I bought in the recent years shipped with ARRE and ARWE set.
Any halfway decent fsck tool can just rewrite the b0rked sector and the
drive transparently remaps a spare.

If reiser4 crashes the kernel instead, it's not failure resilient and is
certainly not ready for production.

> I also oppose the ReiserFS-v3.x design philosophy regarding faulty
> storage layer, but in any case where your _live_ data is valuable and
> uptime counts, you _really_should_ use a RAID of some sort.

...and certainly a backup system that gives you FAST access to the data.
RAID doesn't protect against accidents with rm(1) or, worse, wipe(1).

-- 
Matthias Andree

Re: reiserFS?

[Helge Hafting]

On Sun, Jul 16, 2006 at 06:28:31PM +0200, Christian Trefzer wrote:
> On Sun, Jul 16, 2006 at 06:16:31PM +0200, Xavier Roche wrote:
> > > It simply the best filesystem for many kinds of usage patterns.
> > 
> > The most frightening too. Reiserfs might be suitable for very specific
> > appliactions, but to use it in production machine, you need to have
> > some guts.
> > 
> > My last reiserfs partition was blown up two days ago, because of a bad
> > sector, plus a fatal oops, looping endlessly. This was the second
> > time, and the last one, as none of my ext3 filesystems *ever* had
> > similar problems, despite numerous other bad sector issues. Not
> > mentionning the funny "recovery" tool, which generally finishes to
> > trash your data.
> 
> I don't quite understand. You are supposed to dd_rescue the whole block
> device to a working drive and use fsck on the copy.  Whatever is lost in
> the process must of course be restored from a recent backup. But, as a
> friend of mine put it recently, people don't need backup, they only need
> restore ; )
>
Well, many a home user simply doesn't have a a spare block device of 
the same size.  The hassle of reinstalling instead of just waiting
out a fsck is something still.  

The ext filesystems are nice in that they have spare superblocks,
if the main one dies from a bad sector, the spares still work
so you don't loose the entire fs to only a few damaged sectors.

> fsck on a faulty drive might cause even more damage - how do you know
> that other areas of the device are OK? 
>
Somehow, that has saved my day quite a few times with ext2.
I only lost a few files, then went shopping for a new disk. :-)

Helge Hafting