New Ext3 vs ReiserFS benchmarks

An anonymous reader writes "Saw this new benchmark on the linux-kernel mailing list. Although NAMESYS, the developers of ReiserFS has many benchmarks on their site, they only have one Ext3 benchmark. The new benchmark tests Ext3 in ordered and writeback mode versus ReiserFS with and without the notail mount option. Better than expected results for Ext3. Big difference between ordered and writeback modes."

Benchmarks

[prof187]

Granted, you can get some stuff from benchmarks, but I don't really believe them anymore. I mean, you can make a benchmark look good for you by simply using programs that run well w/ it. Don't take this as Linux bashing, because it isn't. I'm just saying that I don't trust benchmarks that much anymore.

my decision

[salmo]

My decision isn't based on performance. They both are "fast enough" for me. I used to use ReiserFS a while back and it was great. Then I installed Redhat 7.3 on a machine and used ext3 so I didn't have to mess with anything. Yes tinkering is fun... but when I feel like it. Sometimes its nice to have stuff Just Work. Haven't had any problems since and have had a few random power outages.

Also I like the idea that I can read the drive with an ext2 driver from an older kernel or from FreeBSD just in case. In case of what? I don't know, but somehow it makes me feel better.

Re:Writeback kicking it

[Zwack]

But if you look at the NAMESYS benchmark comparing ext2 to ext3 and ResierFS then it is clear that for sheer throughput ext2 wins...

IF Speed is your reason for choosing a Filesystem then writeback wins on almost everything in these examples...

But using a Journaled Filesystem isn't usually done for Speed... Unless you count speed booting after a crash. It's done to (more or less) guarantee filesystem integrity after a crash. You may lose data, but you only lose writes that never completed.

So, if you are choosing ext3 with writeback, is it faster than native ext2? I don't know. But it doesn't sound like it is any safer.

Of course, if you're worried about data integrity, you will have a mirror across multiple striped drives using multiple controllers. And then use a Journaled Filesystem to improve boot time.

Z.

Re:Can you document that?

[RockyMountain]

Can you document the claim that hash collisions cause silent data corruption? Or even that they cause a failure of any sort?

If this is true, surely it must be documented somewhere, or have been discussed in a credible forum? I did a little searching, and didn't find anything. Please post a URL to elevate your comment from unsubstantiated rumor to informative information.

In most hash-based indexing algorithms I know of, hash collisions incur a perfomance penalty, but not a data loss.

Re:ext3 writeback vs ext2?

[sjames]

so what's the point of running ext3 in writeback if (as the faq says) it's exactly equivalent to ext2 "with a very fast fsck"?

Consider a large tmp volume.

Anywhere where the consequences of finding stale data in a file are no worse than having the data simply missing after a crash. Even a src directory if you do a lot of big makes (since you're best off with make clean ; make after a crash anyway). Just be sure to sync after writing out a source file.

However, as long as performance is adequate, probably better safe than sorry when it comes to filesystems.

Re:Interesting

[Anonymous Coward]

My car is missing. Therefore, UFOs from the center of the earth took it. Bigfoot was involved.

Why I like reiserfs

[HipPriest]

I like reiserfs because I can trust it to perform well on any file system load. I can put it on a server and know it will be fast and efficient regardless of what the users do. Ext3 gives ext2 journaling, but does not add efficient large directories or small files, two features that reiserfs has.

Sure ext3 may benchmark slightly faster in certain scenarios. But unless you know ahead of time that those are the only scenarios you are going to put on the file system, I recommend reiserfs.

I use both

[JebusIsLord]

I use ext3 in ordered mode for my "/" and "/usr" partitions for its data journaling, and reiserfs with -notail for my /tmp and /pub partitions (pub is an FTP/SMB fileserver, lots of activity). I think this is a good compromise between performance and non-corrupability (sp?)

Re:ReiserFS loses data

[Morgaine]

Let's be scientific about this.

Provide at least one pair of filepaths which generate a hash collision under whatever scenario you care to specify, so that others can test and verify the resulting effect, even if it's probabilistic and requires billions of reruns to trigger -- no problem.

If the effect isn't seen by anyone else under any conditions, then the problem doesn't exist. Conversely, if it does happen under some repeatable conditions (even if only extremely rarely) then it *is* a problem, and will be fixed.

If you want to be constructive about it, take this issue out of mythology and onto firmer ground.