Journaling File Systems and RAID (was RE: [ale] ext3)

[Michael Perigard]

Youre question is a little apples vs oranges.

We run AIX at the office with jfs. We have nfs mounted user directories
and model directories (housing the engineer's and developer's CADD/CAM
files) at sizes ive never seen before or even imagined.  The real
advantage I have seen that jfs has over say, ext2, is the ability to
extend the filesystem at will, without previously allocating that space to
a particular volume. By placing several logical volumes in a volume group,
youre guarenteed that you don't allocate a logical volume more space than
is needed, allowing you very efficient use of your disk space, RAID array
or not.

Allocating your available space to volume groups and then creating and
managing logical volumes within that group eliminates (almost ;) a full
filesystem. We have a very simple cron job that email/pages the proper
people when a filesystem is filling up. This not only keeps the users
happy and things running smoothly, but alerts us to trouble when we see a
filesystem run to capacity a few times during a day (a run away log file,
for example.)

-Michael

On Wed, 19 Sep 2001, Davis, Ricardo C. wrote:

> Hey Stuffy,   :)
> 
> I have storage question.  Why run a journaling file system with RAID 5?
> Isn't this overkill?  What do you gain that you wouldn't with just a RAID 5
> configuration?
> 
> 
> -Ricardo
> 
> -----Original Message-----
> From: Stuffed Crust [mailto:pizza at shaftnet.org]
> Sent: Wednesday, September 19, 2001 6:38 AM
> To: Chris Ricker
> Subject: Re: [ale] ext3
> 
> 
> <<snip!>>
> 
> I have point you to a bank of machines I'm keeping tabs on -- they have
> a 5x73G hardware RAID5, and no write caching at all.  writes are much
> slower than ext2... but a 15 second recovery (vs several hours for ext2)
> is worth the tradeoff, given that we read far more often tan we write.
> (Oh, these machines tend to be fairly loaded)
> 
>  - Pizza

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