Linked by Rahul on Fri 31st Oct 2008 16:12 UTC
Linux InternetNews talks to developers and vendors about the rise of Btrfs as a successor to Ext4. Though Ext4 adds extents, Chris Mason, Btrfs developer noted that BTRFS adds a number of other features beyond that. Among those features are items like snapshotting, online file consistency checks and the ability to perform fast incremental backups. BTRFS (pronounced better FS) is currently under development in an effort led by Oracle engineer Chris Mason. With the support of Intel, Red Hat, HP, IBM, BTRFS could become the engine that brings next generation filesystem capabilities to Linux.
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RE: Funny
by segedunum on Sat 1st Nov 2008 15:31 UTC in reply to "Funny"
segedunum
Member since:
2005-07-06

Another article about Linux filesystems and BtrFS, yet more comments about ZFS :-).

It is funny that some Linux people thinks that preventing silent corruption is not important, when discussing ZFS.

Well, it is and it isn't. Silent corruption is generally the result of problems elsewhere, and in the case of Solaris, usually its the pretty arcane and old device drivers. Unless you're prepared to use ZFS to find out what went wrong and to fix it, the frenzied excitement over ZFS detecting 'silent corruption' is pretty laughable.

In the case of silent corruption as a result of hardware, well, you aren't going to recover anything if you don't have redundancy, regardless of whether you run ZFS or not. In any event, you want to solve the issue rather than detecting it and thinking you're brilliant, and either the hardware gets fixed or you move to something else. Either way, it's a hardware issue and drives in particular need to get better and do their own data integrity checks. That issue will not change with a new filesystem.

Now that BTRFS will support that feature, I promise you that soon these people will say it's the most important thing since sliced bread.

I hope not, because it isn't.

I think they are funny.

I think you're funny. If ZFS (or BtrFS) detects silent corruption then you need to do something about it. If you can't, and in most cases you can't really fix it because it's an esoteric hardware or driver issue, then the feature is essentially useless. You will forever be firefighting and without redundancy you will lose data regardless.

In many ways, its a feature more useful to pass on to kernel developers and hardware manufacturers because they're the ones who can do something about it. I suppose those who can make best use of it will be those with the better development community ;-).

Soon SEGEDUNUM also will change his mind and praise prevention of silent corruption.

Thanks for mentioning me by name, and in capitals no less :-). No, I'm afraid I'm not going to do that for reasons I have described ;-).

But not until Linux has that feature. Until then, detection and prevention of silent corruption is not important.

I'm sorry, but while some form of silent corruption detection is nice, your problems have only just started. I feel for you that silent corruption detection just hasn't generated the level of excitement intended with ZFS, and henceforth Solaris, but there you are.

Edited 2008-11-01 15:34 UTC

Reply Parent Score: 2

RE[2]: Funny
by WereCatf on Sat 1st Nov 2008 16:07 in reply to "RE: Funny"
WereCatf Member since:
2006-02-15

Well, it is and it isn't. Silent corruption is generally the result of problems elsewhere, and in the case of Solaris, usually its the pretty arcane and old device drivers. Unless you're prepared to use ZFS to find out what went wrong and to fix it, the frenzied excitement over ZFS detecting 'silent corruption' is pretty laughable.

Well...detecting corruption is always useful. It means there's an issue somewhere, most likely hardware, and if it is indeed a hardware issue it's good to know about it before it gets worse. The ZFS ability to sometimes fix the corruption is good, but I do consider it more useful to have a warning about malfunctions.

On the other hand, if your system finds corruptions, fixes them, and you are just glad it got fixed and continue whatever you did without checking what the issue is...then you are quite ignorant and in a risk of losing a part or all of your data on the disk. Trusting it to get automatically fixed without your intervention is foolish.

Reply Parent Score: 3

RE[2]: Funny
by Arun on Sat 1st Nov 2008 19:33 in reply to "RE: Funny"
Arun Member since:
2005-07-07


In the case of silent corruption as a result of hardware, well, you aren't going to recover anything if you don't have redundancy, regardless of whether you run ZFS or not. In any event, you want to solve the issue rather than detecting it and thinking you're brilliant, and either the hardware gets fixed or you move to something else. Either way, it's a hardware issue and drives in particular need to get better and do their own data integrity checks. That issue will not change with a new filesystem.


Please elaborate how you go about fixing something you can't even detect?


I think you're funny. If ZFS (or BtrFS) detects silent corruption then you need to do something about it. If you can't, and in most cases you can't really fix it because it's an esoteric hardware or driver issue, then the feature is essentially useless. You will forever be firefighting and without redundancy you will lose data regardless.


Again if you have no clue it is happening how do you go about fixing it?

In many ways, its a feature more useful to pass on to kernel developers and hardware manufacturers because they're the ones who can do something about it. I suppose those who can make best use of it will be those with the better development community ;-).


Again if the end user can't detect corruption since it is "silent" how does one inform the developers or hardware guys?



I'm sorry, but while some form of silent corruption detection is nice, your problems have only just started. I feel for you that silent corruption detection just hasn't generated the level of excitement intended with ZFS, and henceforth Solaris, but there you are.


The only place it hasn't generated any excitement is in your head. Everyone else including BTRFS developers and Gentoo developers took notice and are doing something about it. Meanwhile you are still trumpeting a very flawed view point.

http://storagemojo.com/2007/09/19/cerns-data-corruption-research/

CERN did silent data corruption research and found it to be a major problem.

Here is the link to the paper:
http://indico.cern.ch/getFile.py/access?contribId=3&sessionId=0&res...

Edited 2008-11-01 19:50 UTC

Reply Parent Score: 3

RE[3]: Funny
by segedunum on Sun 2nd Nov 2008 22:06 in reply to "RE[2]: Funny"
segedunum Member since:
2005-07-06

Please elaborate how you go about fixing something you can't even detect?

The odds are that you can't fix it anyway, so you're screwed either way - unless you have redundancy regardless. If you have redundancy then that's the only way you will be OK. Either that or you use an OS with decent device drivers or change your hardware ;-).

Again if you have no clue it is happening how do you go about fixing it?

You use something that works to start off with, or you switch mighty quick. Whatever happens, you're screwed without redundancy no matter what silent corruption you think you've detected, or what you can't detect either.

Again if the end user can't detect corruption since it is "silent" how does one inform the developers or hardware guys?

Users can't inform the developers or hardware guys because you won't know what has been detected at all and won't be able to give them anything. It will only be useful as a troubleshooting tool for developers to work through something that is reproducible.

The only place it hasn't generated any excitement is in your head. Everyone else including BTRFS developers and Gentoo developers took notice and are doing something about it. Meanwhile you are still trumpeting a very flawed view point.

Yer, it's created a moderate amount of excitement - amongst developers. They will use it to recreate scenarios where corruption has taken place, find out what has happened in various device drivers and/or inform hardware manufacturers what has been going wrong with their hardware. Users will feel the indirect benefits of it but they will carry on as they have always done because they can't do much about it.

CERN did silent data corruption research and found it to be a major problem.

Good for them. Did they actually go through 20TB of their own data and actually find out how much corruption they had, did they actually fix anything or did they just produce some numbers? ;-)

Edited 2008-11-02 22:06 UTC

Reply Parent Score: 2