Re: Sun ZFS vs. Oracle ASM

"Vikas Agnihotri" <usenet_at_vikas.mailshell.com> wrote in message news:358ombF4iks6aU1_at_individual.net...
> Refer to
>
> http://www.sun.com/2004-0914/feature/index.html
>
> This sounds uncannily like the new ASM feature in Oracle 10g?
>
> So 10g+ASM on this new ZFS filesystem would be overkill. Either use ASM
> with raw disks or non-ASM with ZFS?

Well as currently Oracle is not supported on solaris 10 according to metalink using it in production is probably an error.

That said there is no reason not to use both and use the external redundancy setting for your database files if you wish to entrust redundancy/integrity rather than striping to ZFS

> ZFS looks like interesting technology. They seem to have made the
> filesystem fully transactional with almost a 2-phase commit.

I didn't see that from the article, it looked to me like they are guaranteeing the integrity of disk operations with recoverability via snapshots.

> ZFS, Oracle 10g ASM, Veritas suite of products, sheesh...so many options
> to do essentially the same thing!

They don't do quite the same thing. ZFS provides easily managed large and easily extensible filesystems over a pool of storage. ASM provides striping mirroring and data redundancy as well as eliminating datafile management whilst veritas provides volume management. All in the same area yes, not necessarily the same features.

In addition there was one particular piece in the article that worried me (well apart from the suggestion that 128bit storage pools if filled would boil the oceans!) and that was this.

"We've rethought everything and rearchitected it," says Jeff Bonwick, Sun distinguished engineer and chief architect of ZFS. "We've thrown away 20 years of old technology that was based on assumptions no longer true today."

Why does this worry me, well that is kind of summed up in the Joel on Software article below.

http://www.joelonsoftware.com/articles/fog0000000069.html

Now as it happens I doubt that they really did throw away all the old stuff (and dtrace is just waiting to compare the code to prove or disprove this) but it is very very rare that throwing everything out is a good idea - and filesystems have pretty much worked for the last 20+ years perfectly well.

-- 
Niall Litchfield
Oracle DBA
http://www.niall.litchfield.dial.pipex.com