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_at_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_at_gridapp.com> To: dannorris_at_dannorris.com; VIVEK_SHARMA_at_infosys.com; oracle-l_at_freelists.org 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_at_gridapp.com
http://www.gridapp.com



-----Original Message-----
From: oracle-l-bounce_at_freelists.org on behalf of Dan Norris
Sent: Thu 12/6/2007 7:51 AM
To: VIVEK_SHARMA_at_infosys.com; oracle-l_at_freelists.org
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_at_infosys.com>
To: "oracle-l_at_freelists.org" <oracle-l_at_freelists.org>
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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