Looking for Advice on XFS vs. ReiserFS

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trmentry

Weaksauce
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I'm looking for opinions on using XFS or ReiserFS for large raid arrays. My current setup is 8x400 using LVM2 to partition it and ReiserFS. But I was going to use The Hunters technique to go to 8x750 and was wondering if it would be better to bring up the 8x750 as new array and make it XFS instead and then copy data around.

But I've read XFS can crash machines. I've not had any troubles with ReiserFS but have heard its not the greatest choice in a raid5 array.

Thanks
 
I can only offer an anecdote - my friend's 8disk software RAID5 server took 2 minutes to mount the Reiser filesystem that was created on the array, whereas my XFS mounts instantly for my 8disk soft RAID5 server. He has since switched over to XFS and has no problem.

If anyone has any ideas why he might have seen this phenomenon, please chime in - I'm running Gentoo, he's running Ubuntu Server.

A second friend also had a noticeable delay when mounting reiser partitions when using Ubuntu. Is this a Ubuntu specific problem? I've never seen any of these delays when mounting reiser on Gentoo.
 
trmentry said:
I'm looking for opinions on using XFS or ReiserFS for large raid arrays. My current setup is 8x400 using LVM2 to partition it and ReiserFS. But I was going to use The Hunters technique to go to 8x750 and was wondering if it would be better to bring up the 8x750 as new array and make it XFS instead and then copy data around.

But I've read XFS can crash machines. I've not had any troubles with ReiserFS but have heard its not the greatest choice in a raid5 array.
Click to expand...

XFS makes assumptions that the machine is correct, and that data written to disk will actually get written. So you need to have Prime95-stable hardware, and a system that ensures the machine will shut down cleanly in the event of a power failure. Then, and only then, XFS is a good choice.
 
Boomslang said:
I can only offer an anecdote - my friend's 8disk software RAID5 server took 2 minutes to mount the Reiser filesystem that was created on the array, whereas my XFS mounts instantly for my 8disk soft RAID5 server. He has since switched over to XFS and has no problem.

If anyone has any ideas why he might have seen this phenomenon, please chime in - I'm running Gentoo, he's running Ubuntu Server.

A second friend also had a noticeable delay when mounting reiser partitions when using Ubuntu. Is this a Ubuntu specific problem? I've never seen any of these delays when mounting reiser on Gentoo.
Click to expand...

Large Reiserfs volumes take a long time to mount. I can personally attest to that. It's a well known drawback of the filesystem.
 
Here's an interesting read from one of the Reiserfs maintainers. FYI, BKL refers the the Big Kernel Lock in that email. I found out about that while looking into a performance issue triggered by beating on several large Reiserfs partitions simultaneously.

On a related note, Chris Mason (who now works for Oracle) is currently working on Btrfs, which is a next-gen filesystem for Linux that looks very nice. Has anybody here tried out the prototype yet? Here is the official website for it.
 
unhappy_mage said:
XFS makes assumptions that the machine is correct, and that data written to disk will actually get written. So you need to have Prime95-stable hardware, and a system that ensures the machine will shut down cleanly in the event of a power failure. Then, and only then, XFS is a good choice.
Click to expand...

I have plenty of UPS power for the server. SmartUPS 2000. And I just swapped the batteries out a few months ago for new ones. Had a power outage while back and stayed up for over 1.5 hours. The only reason I shut everything down at that point was the annoying beeping from the UPS was getting to me.

I just ordered my new stuff from Newegg.
o Celeron D 532
o Asus P5GC-VM
o 4g DDR2

Going to slap that all into a case and bring up the new drives on new machine and copy data over. Once that's done, add the old drives to the machine as a separate array.

I think XFS is the way I'm going to head.

Thanks for input.
 
Didn't the guy who designed ReiserFS get convicted of murder?

If you're anti-murder then I guess your only choice is XFS..

Riley
 
Skud said:
Didn't the guy who designed ReiserFS get convicted of murder?

If you're anti-murder then I guess your only choice is XFS..

Riley
Click to expand...

No. He's being held as a suspect, but the case isn't cut-and-dried. See Wikipedia. Opening statements October 29th.
 
The choice of filesystem depends a lot on what the array is going to be used for.

For tons of small files (small = less than 1mb, for example) then reiserfs pwns everything else. It is unbelievably quick with small files, but is more prone to fragmentation than other filesystems and as others have mentioned it is kinda clunky when used on huge volumes.

For large files (i.e. dvd backups) XFS pwns. It also performs better than other filesystems on nearly-full drives (most filesystems trail off in performance after about 90% capacity, xfs can go entirely full and still be fast). It was designed to be used on huge volumes so it mounts/umounts very quickly and has gigantic maximum volume/file sizes.

There is one caveat to make here: XFS volumes cannot be shrunk, only expanded. Do not use XFS if you think you may want to shrink your volumes.

Also, for whatever filesystem you choose, please research your choice of kernel sources very carefully: some kernel versions have known corruption issues with these filesystems. Your comment about XFS "crashing machines," however, really has no merit. It is no less stable than any other filesystem.

Overall, I would recommend XFS for a project like this, as this is precisely what XFS was made for, but please do heed the warnings about the need for a stable machine.
 
Boomslang said:
I can only offer an anecdote - my friend's 8disk software RAID5 server took 2 minutes to mount the Reiser filesystem that was created on the array, whereas my XFS mounts instantly for my 8disk soft RAID5 server. He has since switched over to XFS and has no problem.
Click to expand...

I had this problem, Gentoo amd64 as the distro. I then moved to XFS, and XFS started to deteriorate under my feet. Now I run ext3 without any problems.
 
Eva_Unit_0 said:
There is one caveat to make here: XFS volumes cannot be shrunk, only expanded. Do not use XFS if you think you may want to shrink your volumes.
Click to expand...

Interesting. I wasn't aware of that limitation. Thank you. I tend to not shrink my volumes, but lately I've been doing that to get more space for the volume that has only 120g free out of 1.5T *cough*

I'm hoping to build the new machine and not have to worry about shrinking but only growing. :)
 
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