Re: Cluster File System Versus ASM for RAC Deployment in Production?... Pros & Cons

>> However, OCFS2 has no capability
 for growing filesystems, creating situations where using OCFS2 for
 datafiles means increasing the number of mounts over time, which gets
 messy.

That's incorrect. "tunefs.ocfs2 -S /dev/sde1" will grow the FS to the size of 
the partition where it resides. Just tested it this week:



[root@ch-srlxdb01 ~]#
tunefs.ocfs2 -S /dev/sde1


tunefs.ocfs2 1.2.7


Changing volume size from
1309649 blocks to 1834541 blocks


Proceed (y/N): y


Resized volume


Wrote Superblock




----- Original Message ----
From: Matthew Zito <mzito@xxxxxxxxxxx>
To: dannorris@xxxxxxxxxxxxx; VIVEK_SHARMA@xxxxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Sent: Thursday, December 6, 2007 8:29:24 AM
Subject: RE: Cluster File System Versus ASM for RAC Deployment in 
Production?... Pros & Cons



I always recommend using both ASM and a CFS, where appropriate.  For
 example, on Linux systems, where there is a free, Oracle-supported CFS
 (OCFS2), I recommend making a small OCFS2 filesystem (or two) for storage
 of OCR and voting files.  Then, make the primary datafile/index/log
 storage on ASM.  Optionally, they can then have a large dump or backup
 filesystem that is OCFS2, or NFS - but I always recommend keeping an
 archive location outside of ASM, so if the ASM instance won't start up, you
 can at least get to your archive logs, and presumably you're doing
 backups or a standby database somewhere.  

The reason for using both ASM and CFS on Linux is because dealing with
 multiple block devices for the various OCR and Voting devices is
 annoying and complex, and typically you'll end up wasting a lot of disk space
 (i.e. allocating an 8GB lun for a 100MB ocr device).  By using a
 clustered file system, you can put multiple objects on the one disk, and if
 necessary, store other things there.  However, OCFS2 has no capability
 for growing filesystems, creating situations where using OCFS2 for
 datafiles means increasing the number of mounts over time, which gets
 messy.  ASM solves that problem for you by doing very basic striping.

Thanks,
Matt

--
Matthew Zito
Chief Scientist
GridApp Systems
P: 646-452-4090
mzito@xxxxxxxxxxx
http://www.gridapp.com



-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx on behalf of Dan Norris
Sent: Thu 12/6/2007 7:51 AM
To: VIVEK_SHARMA@xxxxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: Re: Cluster File System Versus ASM for RAC Deployment in
 Production?... Pros & Cons
 
Personally, I'd choose ASM and recommend it to all my customers. This
 is partly because: 1) Oracle recommends it, 2) if Oracle recommends
 something, they generally support it better than things they don't
 recommend, 3) it doesn't cost extra money, and 4) I think ASM is a fine product
 that does its job well (admittedly better in 11g than 10g, but that's
 not your question). 

I think that using a CFS requires training for system admins while ASM
 would also require training, but possibly for the DBAs instead of the
 sysadmins. Typically, I still see ASM being managed by DBAs even though
 it really isn't a database. Many companies have the DBAs manage
 anything with the word Oracle stamped on it.

For docs or links, see otn.oracle.com/asm.

Dan

----- Original Message ----
From: VIVEK_SHARMA <VIVEK_SHARMA@xxxxxxxxxxx>
To: "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
Sent: Wednesday, December 5, 2007 9:08:21 PM
Subject: RE: Cluster File System Versus ASM for RAC Deployment in
 Production?... Pros & Cons

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