Re: ASM versus Filesystems

From: Thomas Roach <>
Date: Mon, 8 Mar 2010 16:52:20 -0500
Message-ID: <>


You make some very excellent points. I think "it depends" is a perfectly good answer because there are so many factors/needs that not any one thing is going to win out here.

One thing I love about ASM is that it lets me balance luns in and out of ASM while eliminating database downtime. Are there other ways to get around this? Are there options to resize things on the fly? Absolutely, but ASM has worked well for me. For others it might be a different story because of comfort levels with existing technology, other needs and / or learning curves of learning a new technology.

Me personally, I prefer ASM or DirectNFS over things like using just raw devices. I would take a filesystem any day over just raw devices :)


On Mon, Mar 8, 2010 at 3:28 PM, Jakub Wartak <>wrote:

> Dnia poniedziaƂek, 8 marca 2010 09:34, Stefano Cislaghi napisaƂ:
> > Hello,
> >
> > despite all data and stats IMHO ASM sucks. ASM is an additional layer,
> > managed through an Oracle instance to manage files in a strange
> manner.I've
> > never seen a big oracle installation, for example in a TLC environment
> > where I work using ASM. All tests over ASM usually fails. Actually use of
> > pure raw devices should be preferable, better if using 8gbit fiber
> instead
> > iscsi on a 1gb ethernet. Yes, managing raw devices is not easy and
> usually
> > is not a DBA work. Also, type of storage is really important.
> >
> I would say yes but it really depends. AIX can use cio/dio
> (concurrent/direct
> I/O via special mount options, even on NFSv3), Solaris is the same, Linux
> has
> O_DIRECT, everything else doesn't count (kill me, but I think HPUX is
> dying...)
> If you have direct I/O & no bottlenecks with mutexes in kernel for single
> inode on JFS2/EXT3/whatever what's the point having ASM on database without
> RAC?
> What's the point having ASM in non-RAC datatabase enviorniment where
> storage
> is being administered by storage/UNIX stuff (company policy!) while AIX's
> can do essentially the same (and also e.g. AIX+Oracle covers
> resilvering/mirror write consistency (MWR) for LVs - when writing to two
> storage arrays)...
> Now if there is RAC on AIX, it still depends do you need legacy solutions
> like
> Veritas/OCFS2 when you can choose simply to use ASM. But you can still use
> NFS(with cio,dio) or even DirectNFS (11g+, which even should use zero-copy
> I/O and TCP offloads on e.g. Linux 2.6)...
> I think there are just too many variables to blindly make statement "use
> ASM"
> or "use NFS". Keep in mind that "Mr. Murphy" has audit-like access to all
> of
> those solutions ;) so the main thing should be: you should have staff
> prepared and familiarized with each of those products/technologies. YMMV.
> --
> Jakub Wartak
> --

Thomas Roach

Received on Mon Mar 08 2010 - 15:52:20 CST

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