[Beowulf] Rackable / SGI

[Joe Landman]

Mark Hahn wrote:

> from my position, XFS was a semi-fringe option for people who distrusted 
> ext3 for some reason.  (and there were a few solid ones, mainly just 
>  >8TB.)  going forward, I expect to use ext4

Hmmmm... rather odd view.  xfs has been around quite a bit longer than 
ext3.  It has been, realistically, the only serious choice for big/fast 
data systems on Linux for quite some time.  Ext3 has some serious 
performance limits due to its journaling design.  Never mind its other 
issues.  There was mention of this in this past week's LWN.net.

I wouldn't use ext3 for anything other than small partitions (100 GB or 
so).  Too many cases seeing the fsck need to get triggered for some 
reason ... the wait is horrible.

> and probably btrfs; I don't see a lasting impact of XFS.

I don't see many people moving hundreds of TB off XFS onto something 
without a really good reason (and other people running into the other 
things bugs).

> if IBM did buy Sun and made an effort to get ZFS Linux-ized
> (Linus-ized), it would be interesting.  especially if they also did so 
> with Lustre.

btrfs is interesting, and it looks like it will be a very important FS 
player.  ext4 looks like it will become the ext3 of the next 5 years. 
There, a default for some, but not what you should use for big/fast data.

Zfs is not the revealed word of some deity, in file systems.  This mind 
set is painful to deal with, and often winds up with people having 
*very* unrealistic expectations of what it is, what it can do, and how 
it performs.  Our experience in speaking to customers about it, suggests 
that the primary reason why there is interest in it, is ease of 
management.  There are some who are interested in the data integrity 
bits.  This said, it ain't perfect.  It has bugs, and people have been 
bitten by them.

All file systems have bugs.

Anyone saying something different is trying to sell you something.


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Joseph Landman, Ph.D
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