Re: Filesystem corruption

2007-05-30 Thread David Masover
On Tuesday 29 May 2007 07:36:13 Toby Thain wrote:

> >> but you can't
> >> mention using reiserfs in mixed company without someone accusing
> >> you of
> >> throwing your data away.
>
> People who repeat this rarely have any direct experience of Reiser;
> they repeat what they've heard; like all myths and legends they are
> transmitted orally rather than based on scientific observation.

Well, there is one problem I vaguely remember that I don't think has been 
addressed, I think it was one of those lets-put-it-off-till-v4 things. It was 
the fact that there are a limited number of inodes (or keys, or whatever you 
call a unique file), and no way of knowing how many you have left until your 
FS will suddenly, one day refuse to create another file.

(For comparison, ext3 seems to support not only telling you how many inodes 
you have left, but tuning that on the fly.)

But, I haven't run into that, and the only problem I've had lately has been 
Reiser4 losing data, and crashing occasionally. I switched most of my data 
off of Reiser4 and onto XFS for that reason. I've also been using ext3 in 
some places, and Reiser3 in others (one place in particular where space is 
limited, but I will have tons of small files).

I later learned that XFS does out-of-order writes by default, making me think 
I should give up and invest in UPS hardware. But, switching away from Reiser4 
means I no longer see random files (including stuff in, for example, /sbin, 
that I hadn't touched in months) go up in smoke.

Ordinarily I like to help debug things, but not at the risk of my data. Maybe 
I'll try again later, and see if I can reproduce it in a VM or somewhere 
safe...

I do still follow the list, though, in case something interesting happens. It 
was fun while it lasted!


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Re: Filesystem corruption

2007-05-30 Thread Vladimir V. Saveliev
Hello

On Wednesday 30 May 2007 17:25, David Masover wrote:
> On Tuesday 29 May 2007 07:36:13 Toby Thain wrote:
> 
> > >> but you can't
> > >> mention using reiserfs in mixed company without someone accusing
> > >> you of
> > >> throwing your data away.
> >
> > People who repeat this rarely have any direct experience of Reiser;
> > they repeat what they've heard; like all myths and legends they are
> > transmitted orally rather than based on scientific observation.
> 
> Well, there is one problem I vaguely remember that I don't think has been 
> addressed, I think it was one of those lets-put-it-off-till-v4 things. It was 
> the fact that there are a limited number of inodes (or keys, or whatever you 
> call a unique file), and no way of knowing how many you have left until your 
> FS will suddenly, one day refuse to create another file.
> 

reiserfs is limited to ~2^32 file creations. It is possible to exhaust but I do 
not remember any reports about that.

> (For comparison, ext3 seems to support not only telling you how many inodes 
> you have left, but tuning that on the fly.)
> 
> But, I haven't run into that, and the only problem I've had lately has been 
> Reiser4 losing data, and crashing occasionally. I switched most of my data 
> off of Reiser4 and onto XFS for that reason. I've also been using ext3 in 
> some places, and Reiser3 in others (one place in particular where space is 
> limited, but I will have tons of small files).
> 
> I later learned that XFS does out-of-order writes by default, making me think 
> I should give up and invest in UPS hardware. But, switching away from Reiser4 
> means I no longer see random files (including stuff in, for example, /sbin, 
> that I hadn't touched in months) go up in smoke.
> 
> Ordinarily I like to help debug things, but not at the risk of my data. Maybe 
> I'll try again later, and see if I can reproduce it in a VM or somewhere 
> safe...
> 
that would be great, thanks

> I do still follow the list, though, in case something interesting happens. It 
> was fun while it lasted!
> 


Re: Filesystem corruption

2007-05-30 Thread Vladimir V. Saveliev
Hello

On Tuesday 29 May 2007 16:36, Toby Thain wrote:
> >>  I have always found reiser3 to be rock solid
> 
> My experienced too, over many server years.
> 
> >> but you can't
> >> mention using reiserfs in mixed company without someone accusing  
> >> you of
> >> throwing your data away.
> 
> People who repeat this rarely have any direct experience of Reiser;  
> they repeat what they've heard; like all myths and legends they are  
> transmitted orally rather than based on scientific observation.
> 
well, there were in past several bad stories when reiserfsck was unable restore 
filesystems because it was unable to find
reiserfs metadata.
Later we found that sometimes (for unknown (but not likely due to reiserfs 
problem) reason) partition table changes so that 
beginning of a partition gets shifted by few sectors. So, now, when a user 
reports that reiserfs metadata disappered from a device completely - recovering 
a partition table to 
original state makes data available again.

> >> You would think the developers would be doing
> >> more to counter this but I have been following reiserfs for years and
> >> nobody seems to really care all that much.
> >>
> 
> Can't do much about human nature. MySQL suffers from the same  
> baseless poisoned folk wisdom.
> 
> --Toby
> 
> 


Re: Filesystem corruption

2007-05-30 Thread Toby Thain


On 30-May-07, at 10:25 AM, David Masover wrote:


On Tuesday 29 May 2007 07:36:13 Toby Thain wrote:


but you can't
mention using reiserfs in mixed company without someone accusing
you of
throwing your data away.


People who repeat this rarely have any direct experience of Reiser;
they repeat what they've heard; like all myths and legends they are
transmitted orally rather than based on scientific observation.


Well, there is one problem I vaguely remember that I don't think  
has been
addressed, I think it was one of those lets-put-it-off-till-v4  
things. It was
the fact that there are a limited number of inodes (or keys, or  
whatever you

call a unique file),


But does it cause data loss? One usually sees claims that "reiserfs  
ate my data", or "I heard reiserfs ate somebody's data", but without  
supplying a root cause - bad memory? powerfail? bad disk? etc.



and no way of knowing how many you have left until your
FS will suddenly, one day refuse to create another file.




... switching away from Reiser4
means I no longer see random files (including stuff in, for  
example, /sbin,

that I hadn't touched in months) go up in smoke.


I only wish sanity had prevailed over  kernel inclusion, then we'd  
see it shaken down a lot quicker, like R3 was.




Ordinarily I like to help debug things, but not at the risk of my  
data. Maybe
I'll try again later, and see if I can reproduce it in a VM or  
somewhere

safe...

I do still follow the list, though, in case something interesting  
happens.


Yeah, R4 is "something interesting". :) I still hope it gets finished...

--Toby


It
was fun while it lasted!




Re: Filesystem corruption

2007-05-30 Thread devsk
I think people just like to spread FUD without doing any analysis of what 
really caused the FS corruption. It can be anything from a bad 3rd party driver 
to bad hardware ('bad blocks', does anybody check for them before mkfs these 
days? I do). People also like to try those untested patchsets, containing every 
blah that's thrown out by so called 'kernel hackers' which makes your system 
10x faster. Rieser4 seems like an easy candidate to vent their anger on 
afterwards.

I have used R4 for a year now and I have had to reset my PC, troubleshooting 
problems with vmware/mythtv/cisco vpn client/nvidia, so many times that its not 
even funny! And R4 didn't give me any problems even once. It boots right up, 
without any files lost and consistent FS as a subsequent livecd boot and fsck 
proved it everytime. If I did that to ext or xfs, I would have lost big time. 
Only files I have ever lost were on ext3 during a sudden power failure. I don't 
trust safety of my data on any FS but Rieserfs. I hope people don't leave this 
good piece of code to rot!!

-devsk

- Original Message 
From: Toby Thain <[EMAIL PROTECTED]>
To: David Masover <[EMAIL PROTECTED]>
Cc: ReiserFS List 
Sent: Wednesday, May 30, 2007 9:42:01 AM
Subject: Re: Filesystem corruption


On 30-May-07, at 10:25 AM, David Masover wrote:

> On Tuesday 29 May 2007 07:36:13 Toby Thain wrote:
>
 but you can't
 mention using reiserfs in mixed company without someone accusing
 you of
 throwing your data away.
>>
>> People who repeat this rarely have any direct experience of Reiser;
>> they repeat what they've heard; like all myths and legends they are
>> transmitted orally rather than based on scientific observation.
>
> Well, there is one problem I vaguely remember that I don't think  
> has been
> addressed, I think it was one of those lets-put-it-off-till-v4  
> things. It was
> the fact that there are a limited number of inodes (or keys, or  
> whatever you
> call a unique file),

But does it cause data loss? One usually sees claims that "reiserfs  
ate my data", or "I heard reiserfs ate somebody's data", but without  
supplying a root cause - bad memory? powerfail? bad disk? etc.

> and no way of knowing how many you have left until your
> FS will suddenly, one day refuse to create another file.
>

> ... switching away from Reiser4
> means I no longer see random files (including stuff in, for  
> example, /sbin,
> that I hadn't touched in months) go up in smoke.

I only wish sanity had prevailed over  kernel inclusion, then we'd  
see it shaken down a lot quicker, like R3 was.

>
> Ordinarily I like to help debug things, but not at the risk of my  
> data. Maybe
> I'll try again later, and see if I can reproduce it in a VM or  
> somewhere
> safe...
>
> I do still follow the list, though, in case something interesting  
> happens.

Yeah, R4 is "something interesting". :) I still hope it gets finished...

--Toby

> It
> was fun while it lasted!








   
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Re: Filesystem corruption

2007-05-30 Thread Toby Thain


On 30-May-07, at 2:22 PM, devsk wrote:

I think people just like to spread FUD without doing any analysis  
of what really caused the FS corruption.


I fear you're right. OTOH, filesystem developers on this list (and  
others including ZFS list) tend to be extremely meticulous.


--Toby



Re: Filesystem corruption

2007-05-30 Thread David Masover
On Wednesday 30 May 2007 11:42:01 Toby Thain wrote:

> But does it cause data loss? One usually sees claims that "reiserfs
> ate my data", or "I heard reiserfs ate somebody's data", but without
> supplying a root cause - bad memory? powerfail? bad disk? etc.

Power failure shouldn't kill a filesystem, and generally shouldn't eat data 
that was written to disk before the failure. (Although I could complain all 
day here about why corruption happens anyway when you do any kind of 
out-of-order operations...  I am looking forward to that Reiser4 transaction 
API, so we can finally get rid of the tmpfile+rename hack.)

But in any case, there were some kernels -- 2.4.16, I think? -- in which 
reiserfs was unstable and did corrupt easily. I believe that was tracked down 
to kernel bugs outside of reiserfs.


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Re: Filesystem corruption

2007-05-30 Thread David Masover
On Wednesday 30 May 2007 12:22:17 devsk wrote:

> I have used R4 for a year now and I have had to reset my PC,
> troubleshooting problems with vmware/mythtv/cisco vpn client/nvidia, so
> many times that its not even funny! And R4 didn't give me any problems even
> once. It boots right up, without any files lost and consistent FS as a
> subsequent livecd boot and fsck proved it everytime.

That happened to me for maybe a year or so, I'm not sure. Then, slowly, I 
started to get problems. The machine crashing due to some nvidia bug -- or 
even a reiser-specific oops or something -- then I'd have to fsck it, which 
would take an hour or more, then I'd boot, and apparently no problems.

Only, recently, these fsck-a-thons started happening more and more often, and 
I started to lose random files. They'd just be silently truncated to 0 bytes. 
And not files I was writing a lot -- I'm talking about things 
like /bin/mount.

Now, maybe it's an amd64-specific bug. Or (somehow) a dmraid-specific bug, or 
a dont_load_bitmap bug. (Who can blame me; without dont_load_bitmap, it takes 
at least 30 seconds, maybe a minute to mount.) Could even be, somehow, a 
Gentoo-specific bug. Could be a 350-gig-partition bug, or even a bug of the 
it-hates-me variety. (My server ran Reiser4 for awhile longer, with no 
problems, but I wasn't about to take chances there.)

But, I switched a friend over to Ubuntu, and he had the same kind of problems. 
In fact, he had them first (I thought it was his computer, for awhile).

Finally, we switched to stock Ubuntu kernels and XFS, me on dmraid, him on 
normal linux raid5 (md), and we now have no problems. It's even faster -- the 
biggest gain for Reiser4 was /usr/portage, which doesn't exist on Ubuntu.

> If I did that to ext 
> or xfs, I would have lost big time.

Well, I'm on XFS on my desktop now, and ext3 on my server. No problems at all 
so far. Also much faster, because my desktop now has a repacker (xfs_fsr).

> I hope people don't leave this good piece of code to rot!!

Me too, but you know, I can no longer afford to spend a few hours running fsck 
for no apparent reason. I no longer have a machine that can do anything but 
just work.

The killer feature of Reiser4, as implemented, is small file performance that 
makes ReiserFSv3 weep, and v3 makes XFS weep. All the other stuff we were 
promised is either planned for a later release (repacker, pseudofiles, 
transaction API) or barely working (cryptocompress).

And on just about any setup I work on today, small file performance is a small 
enough priority that even the slightest hint of instability is a 
deal-breaker. Enough people feel the same way that ext3 is still widely used. 
And if it's ever really crucial, there's reiserfs3.

So, you can blame it on my hardware, or on not getting kernel inclusion, or 
anything you want, but the only place I still use Reiser4 is on the 
gameserver at our LAN party, and we're thinking of moving that to something 
like ext3 or xfs, just so we don't need custom kernels. And after all, that's 
a gameserver, it's not like the filesystem is the bottleneck anyway.


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Re: Filesystem corruption

2007-05-30 Thread David Masover
On Wednesday 30 May 2007 11:02:26 Vladimir V. Saveliev wrote:

> > Ordinarily I like to help debug things, but not at the risk of my data.
> > Maybe I'll try again later, and see if I can reproduce it in a VM or
> > somewhere safe...
>
> that would be great, thanks

Keep in mind, it's unlikely, given I don't have much resembling my original 
setup left around. And it was fairly random, under fairly normal usage 
patterns -- just I'd suddenly notice my movie had stopped playing, and I'd 
hit ctrl+alt+f8 and find a bunch of reiser4 error messages.

Is it at all likely that this is an amd64 bug? (The only two places I've seen 
it are on my box and my friend's, both amd64 on some sort of RAID.) If you 
don't have enough testers or hardware for amd64, I can try (again) to setup a 
working x86_64 VM for you to test on.


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Re: Filesystem corruption

2007-05-30 Thread devsk
David, Its funny how my setup is very similar to yours: gentoo, amd64, nvraid 
using dmraid. mount/mkfs is VERY fast (less than a second) here, and I don't 
use any specific mount options except noatime. My partition is about 16GB 
though, hosting '/' and /home.

what sources do you use? I use gentoo-sources (currently using 2.6.21-r2) with 
the latest stable patch (currently 2.6.21) from namesys, applied manually. 
Nothing else. I use suspend-to-ram (with a UPS) and the whole system is rock 
solid.

-devsk

- Original Message 
From: David Masover <[EMAIL PROTECTED]>
To: devsk <[EMAIL PROTECTED]>
Cc: Toby Thain <[EMAIL PROTECTED]>; ReiserFS List 
Sent: Wednesday, May 30, 2007 1:03:14 PM
Subject: Re: Filesystem corruption

On Wednesday 30 May 2007 12:22:17 devsk wrote:

> I have used R4 for a year now and I have had to reset my PC,
> troubleshooting problems with vmware/mythtv/cisco vpn client/nvidia, so
> many times that its not even funny! And R4 didn't give me any problems even
> once. It boots right up, without any files lost and consistent FS as a
> subsequent livecd boot and fsck proved it everytime.

That happened to me for maybe a year or so, I'm not sure. Then, slowly, I 
started to get problems. The machine crashing due to some nvidia bug -- or 
even a reiser-specific oops or something -- then I'd have to fsck it, which 
would take an hour or more, then I'd boot, and apparently no problems.

Only, recently, these fsck-a-thons started happening more and more often, and 
I started to lose random files. They'd just be silently truncated to 0 bytes. 
And not files I was writing a lot -- I'm talking about things 
like /bin/mount.

Now, maybe it's an amd64-specific bug. Or (somehow) a dmraid-specific bug, or 
a dont_load_bitmap bug. (Who can blame me; without dont_load_bitmap, it takes 
at least 30 seconds, maybe a minute to mount.) Could even be, somehow, a 
Gentoo-specific bug. Could be a 350-gig-partition bug, or even a bug of the 
it-hates-me variety. (My server ran Reiser4 for awhile longer, with no 
problems, but I wasn't about to take chances there.)

But, I switched a friend over to Ubuntu, and he had the same kind of problems. 
In fact, he had them first (I thought it was his computer, for awhile).

Finally, we switched to stock Ubuntu kernels and XFS, me on dmraid, him on 
normal linux raid5 (md), and we now have no problems. It's even faster -- the 
biggest gain for Reiser4 was /usr/portage, which doesn't exist on Ubuntu.

> If I did that to ext 
> or xfs, I would have lost big time.

Well, I'm on XFS on my desktop now, and ext3 on my server. No problems at all 
so far. Also much faster, because my desktop now has a repacker (xfs_fsr).

> I hope people don't leave this good piece of code to rot!!

Me too, but you know, I can no longer afford to spend a few hours running fsck 
for no apparent reason. I no longer have a machine that can do anything but 
just work.

The killer feature of Reiser4, as implemented, is small file performance that 
makes ReiserFSv3 weep, and v3 makes XFS weep. All the other stuff we were 
promised is either planned for a later release (repacker, pseudofiles, 
transaction API) or barely working (cryptocompress).

And on just about any setup I work on today, small file performance is a small 
enough priority that even the slightest hint of instability is a 
deal-breaker. Enough people feel the same way that ext3 is still widely used. 
And if it's ever really crucial, there's reiserfs3.

So, you can blame it on my hardware, or on not getting kernel inclusion, or 
anything you want, but the only place I still use Reiser4 is on the 
gameserver at our LAN party, and we're thinking of moving that to something 
like ext3 or xfs, just so we don't need custom kernels. And after all, that's 
a gameserver, it's not like the filesystem is the bottleneck anyway.







   
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