RE: ASM and RAW Devices on RHEL 4
- From: "Luca Canali" <Luca.Canali@xxxxxxx>
- To: <sanstorage@xxxxxxxxx>, <exriscer@xxxxxxxxx>
- Date: Tue, 7 Mar 2006 20:41:32 +0100
Hi,
I'd advise using devlabel to map rawdevices rather than using
/etc/sysconfig/rawdevices. devlabel provides persistency across
reboots/storage reorgs. I've been using for a while now without any
issues.
By the way, a major plus for asmlib vs. raw for ASM is that it provides
labeling of the disks and therefore persistency against storage changes
and easier setup in multinode installations (much like devlabel in this
respect). Another interesting fact about asmlib is that it reduces the
amount of open file descriptors per process (only 1 is used) which can
increase the overall manageability (and scalability) when you map
several tens of LUNs.
Cheers,
Luca
________________________________
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Raj S
Sent: Tuesday, March 07, 2006 8:16 PM
To: exriscer@xxxxxxxxx
Cc: johan Eriksson; Oracle-L Freelists
Subject: Re: ASM and RAW Devices on RHEL 4
There are no issues using rawdevices for ocr.dbf and votingdisk. They
work just fine. Put them in your /etc/sysconfig/rawdevices and create
the necessary mapping to the shared storage. We have several of these
running fine on raw devices with 10G R2 on RHEL4.
Raj
On 3/7/06, LiShan Cheng <exriscer@xxxxxxxxx> wrote:
Hi
That test is comparing LVM + EXT3 vs ASM + RAW. My comparison
would be ASM + RAW + LINUX I/O API vs ASM + RAW + ASMLIB I/O API.
I am not sure if ASMLib is better or ASM and RAW is enough.
Cheers
LSC
On 3/7/06, johan Eriksson < johan.eriksson@xxxxxxxxxxxx
<mailto:johan.eriksson@xxxxxxxxxxxx> > wrote:
On Tue, 2006-03-07 at 10:54 +0100, LiShan Cheng wrote:
> Hi
>
> I am going to install a 10gR2 RAC in a couple of
weeks. It will be
> RHEL 4 Update 2 and I will be using ASM for all
database files.
> However I have some doubts, I am wondering if ASMLib
API gives better
> performance than Linux standard I/O API? Anyone with
both ASMLib
> experience and ASM + RAW + Linux I/O API?
>
We have just installed this combination but I haven't
tested the
performance yet.
One test is at http://www.linuxjournal.com/article/8539
> I also read this note, Note: 357492.1, Linux 2.6
kernel deprecation of
> raw devices. I was planning to use RAW Devices for the
voting disk and
> OCR files. If raw devices are deprecated does it mean
I must use
> OCFS2?
>
Linux 2.6 and OCFS2 aren't yet cerified so I think you
have to use raw
for ocr and voting (if you care about support)
/johan
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