Troy Dawson wrote:

> Ken Teh wrote:
>
>> I've just installed SL4.1 on a dual opteron 6.4TB disk array system. 
>> This is
>> my first disk array, so I'm full of questions.  The disk array is 
>> configured
>> as one large disk partition.  At 5.6TB, it's larger (according to 
>> what I've
>> read) than what ext3 can handle.  So, I'm thinking of putting either 
>> JFS or
>> XFS on the system.
>>
>> SL4.1's stock kernel does not have built-in JFS nor XFS support.  But 
>> there
>> is a contributed XFS rpm.  Is this the preferred filesystem for large
>> partitions?  If so, why?
>>
>> I don't know the history of XFS, but I first encountered JFS in the 
>> late 80s
>> when I worked on an AIX machine.  Also, I read on the web that JFS has
>> better performance than XFS.
>>
>> Comments??
>>
>> Ken
>
>
> From the Scientific Linux 4.2 release notes
>
>      o The current ext3 file system limit in Scientific Linux 4.2
>        is 8 terabytes. The e2fsprogs package has been updated to
>        adhere to this file system limit.
>
> So it looks like if you use S.L. 4.2 you should be ok with 4.2.
> (OK, so we haven't *officially* released it ... there is one file 
> driving us nuts, but what's in 4.2 is really what's going to be 
> released.)
>
> But the question about the other stuff I think would be good to be 
> answered.  But I'm not really the expert.
>
> This is what I've been told.
>
> XFS - good for very large files
> Reiser - good for lots of small files
>
> Well ... that's not very much information, but all I have at the moment.
>
> Troy

The best way to handle a (very) big disk is to "split" it using lvm 
(plus a resizable filesystem).
In example, you can create four "small" partitions (200GB, ext3), called 
"Project[1234]". If project3 need more space, no problems, you can 
simply resize it whit  lvresize + ext2online (no umount needed!). Lvm 
take care where to expand the partition.
To divide the disk off using lvm have some advantages. First of all if 
you lose a  filesystem, you lose "only" a  part of data (whit new, 
journaled filesystem this accidents are uncommon, but...).

There is a lot of papers about filesystem's difference.
I'm not a expert too, but I think Troy is right.
If you need speed, in my experience the best is reiserfs.
But XFS is really, really (and really again...) more strong, and 
moreover it's designed for big partitions (and big files).
Ext3 is a extreme, tested and used filesystem, therefore if something 
wrong happen to the filesystem, is more simple to save the data (google 
alway give you the answer :) )


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