Reiser vs EXT3
Still working on that replacement mail server and a new rumor has hit
the mix. It follows that reiserfs is much faster than ext3 (made ext3, not converted from ext2 if it matters) and this is causing some problems. On a 200Gig filesystem is this truely an issue?
Thanks,
Robert
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Robert L. Harris
DISCLAIMER:
These are MY OPINIONS ALONE. I speak for no-one else.
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Quoted 5 lines · Robert L. Harris
Still working on that replacement mail server and a new rumor has hit
the mix. It follows that reiserfs is much faster than ext3 (made ext3, not converted from ext2 if it matters) and this is causing some problems. On a 200Gig filesystem is this truely an issue?
ext3 has some SMP scalability problems. The BKL is used to protect many journal operations, and we see huge amounts of CPU spent spinning on it on 4/8/16 proc machines. So much CPU, that it masks anything else we're doing on the system. But, on a single-proc or just a 2-way, you probably won't see much of this to be significant.
We haven't tested reiser extensively here, but from what I've seen it scales much, much better than ext3 (as does jfs and probably xfs too).
Signature · 2 lines
Dave Hansen [email protected]
note that breaking up this locking bottleneckhas been done in the 2.5 kernel series so when 2.6 is released this should be much less significant (Q2 2003 is the current thought, but don't count on it until it's out)
David Lang
Quoted 31 lines · David C. Hansen
Date: 31 Oct 2002 11:02:49 -0800
From: David C. Hansen <[email protected]>
To: Robert L. Harris <[email protected]>
Cc: Linux-Kernel <[email protected]>
Subject: Re: Reiser vs EXT3Quoted 5 lines · Robert L. Harris
Still working on that replacement mail server and a new rumor has hit
the mix. It follows that reiserfs is much faster than ext3 (made ext3, not converted from ext2 if it matters) and this is causing some problems. On a 200Gig filesystem is this truely an issue?ext3 has some SMP scalability problems. The BKL is used to protect many journal operations, and we see huge amounts of CPU spent spinning on it on 4/8/16 proc machines. So much CPU, that it masks anything else we're doing on the system. But, on a single-proc or just a 2-way, you probably won't see much of this to be significant.
We haven't tested reiser extensively here, but from what I've seen it scales much, much better than ext3 (as does jfs and probably xfs too). --
Dave Hansen
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If you want to talk about 2.6 then you should talk about reiser4 not reiserfs v3, and reiser4 is 7.6 times the write performance of ext3 for 30 copies of the linux kernel source code using modern IDE drives and modern processors on a dual-CPU box, so I don't think any amount of improved scalability will make ext3 competitive with reiser4 for performance usages.
We haven't had anyone test performance using RAID yet for reiser4, that could be fun.
Best,
Hans
Quoted 54 lines · David Lang
note that breaking up this locking bottleneckhas been done in the 2.5 kernel series so when 2.6 is released this should be much less significant (Q2 2003 is the current thought, but don't count on it until it's out)
David Lang
Quoted 27 lines · David C. Hansen
Date: 31 Oct 2002 11:02:49 -0800
From: David C. Hansen <[email protected]>
To: Robert L. Harris <[email protected]>
Cc: Linux-Kernel <[email protected]>
Subject: Re: Reiser vs EXT3Quoted 6 lines · Robert L. Harris
Still working on that replacement mail server and a new rumor has hit
the mix. It follows that reiserfs is much faster than ext3 (made ext3, not converted from ext2 if it matters) and this is causing some problems. On a 200Gig filesystem is this truely an issue?ext3 has some SMP scalability problems. The BKL is used to protect many journal operations, and we see huge amounts of CPU spent spinning on it on 4/8/16 proc machines. So much CPU, that it masks anything else we're doing on the system. But, on a single-proc or just a 2-way, you probably won't see much of this to be significant.
We haven't tested reiser extensively here, but from what I've seen it scales much, much better than ext3 (as does jfs and probably xfs too). --
Dave Hansen
[email protected]Quoted 8 lines
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Please read the FAQ at http://www.tux.org/lkml/-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected]
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Signature · 1 line
Hans
Quoted 1 line · Hans Reiser
If you want to talk about 2.6 then you should talk about reiser4 not reiserfs v3, and reiser4 is 7.6 times the write performance of ext3 for 30 copies of the linux kernel source code using modern IDE drives and modern processors on a dual-CPU box, so I don't think any amount of improved scalability will make ext3 competitive with reiser4 for performance usages.
What is the read performance like?
write performance isn't the end-all be-all of useful benchmarks, because most servers do far more reading in a day than they will ever write. And like Andrew has pointed out on more than one occasion, reads are usually synchronous, because applications are typically blocking until each read is satisfied.
Jeff
Quoted 8 lines · Jeff Garzik
Quoted 2 lines
reiser4 is 7.6 times the write performance of ext3
for 30 copies of the linux kernel source code using modern IDE drivesWhat is the read performance like?
write performance isn't the end-all be-all of useful benchmarks, because most servers do far more reading in a day than they will ever write.
I'm not sure how true that is these days. OLTP DB servers with a lot of RAM will typically do more write traffic, all pushed by fsync, than reads. (Some may claim that that means your server is overspecced, of course.)
Other servers, too, look rather like that -- mail servers do a lot of fsync, web servers generally have smallish web trees but write a lot of logs...
Even on data warehousing apps, there will be a fairly high level of writes due to use of temporary relations..
Matthew.
Quoted 9 lines · Hans Reiser
If you want to talk about 2.6 then you should talk about reiser4 not reiserfs v3, and reiser4 is 7.6 times the write performance of ext3 for 30 copies of the linux kernel source code using modern IDE drives and modern processors on a dual-CPU box, so I don't think any amount of improved scalability will make ext3 competitive with reiser4 for performance usages.
We haven't had anyone test performance using RAID yet for reiser4, that could be fun.
I have a 14-drive hardware RAID array on an 8-proc box. Is that the kind of thing you want testing on? If you want to send me some testing scripts, I'll run them.
Signature · 2 lines
Dave Hansen [email protected]
Quoted 3 lines · David Lang
note that breaking up this locking bottleneckhas been done in the 2.5 kernel series so when 2.6 is released this should be much less significant (Q2 2003 is the current thought, but don't count on it until it's out)
Actually, ext3 has been immune from most of the lock breakups in 2.5. ext2 used to have a lot of problems with BKL contention resulting from ext2_get_block() and some other assorted functions. Al Viro cleaned these up in early 2.5, but ext3 never got the cleanup. It still scales horribly, even 2.5.45.
Signature · 2 lines
Dave Hansen [email protected]
Quoted 5 lines · David C. Hansen
Quoted 2 lines · Hans Reiser
If you want to talk about 2.6 then you should talk about reiser4 not reiserfs v3, and reiser4 is 7.6 times the write performance of ext3 for 30 copies of the linux kernel source code using modern IDE drives and modern processors on a dual-CPU box, so I don't think any amount of improved scalability will make ext3 competitive with reiser4 for performance usages.
Quoted 10 lines
Quoted 3 lines
We haven't had anyone test performance using RAID yet for reiser4, that could be fun.
I have a 14-drive hardware RAID array on an 8-proc box. Is that the kind of thing you want testing on? If you want to send me some testing scripts, I'll run them.
Yes, that would be cool.
Green, please respond to this email with details for him.
Signature · 1 line
Hans
Quoted 7 lines · Robert L. Harris
Still working on that replacement mail server and a new rumor has hit
the mix. It follows that reiserfs is much faster than ext3 (made ext3, not converted from ext2 if it matters) and this is causing some problems. On a 200Gig filesystem is this truely an issue?
Have you tried different ext3 journalling modes? Ordered is pretty
slow in many cases. You might want to try writeback instead. The downside is that you might end up losing resently written changes in the event of a crash. Try mounting with "-o data=writeback".