Re: OCR / VD external vs. normal redundancy using NFS.

  • From: David Robillard <david.robillard@xxxxxxxxx>
  • To: "D'Hooge Freek" <Freek.DHooge@xxxxxxxxx>
  • Date: Mon, 5 Jul 2010 16:29:14 -0400

On Thu, Jul 1, 2010 at 1:31 AM, D'Hooge Freek <Freek.DHooge@xxxxxxxxx> wrote:
> I'm usually using the normal redundancy, putting each voting disk / cluster 
> registry in its own volume.
> You might want to read 
>  Because of this "bug" I needed to switch to iscsi for the cluster registry 
> volumes. It is probably still valid with 11gR2

Interesting. Thanks for the heads-up.

I've read your post and the ones from Geert de Paep. What I understand
is that problem seems to exist when you have several OCR disks. But if
you choose "External redundancy" instead of "Normal redundancy" when
you install the Grid Infrastructure software, you end up with a single
OCR disk. Hence this bug would not happen. Right?

But is using "External redundancy" for OCR a bad idea when you have a
single storage array?

Because if that single storage array suffers a catastrophic failure,
you end up loosing not only the OCR disk, but the voting disk and all
database files as well. The entire cluster would be down even with
several OCR disks.

So even if I switch to iSCSI, I would still have the same "single
storage array" problem. Since all LUNs would be stored on that storage

Unless there are other ways for an OCR disk to become corrupted?



> Regards,
> Freek D'Hooge
> Uptime
> Oracle Database Administrator
> email: freek.dhooge@xxxxxxxxx
> tel +32(0)3 451 23 82
> disclaimer:
> -----Original Message-----
> From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
> Behalf Of David Robillard
> Sent: woensdag 16 juni 2010 16:44
> To: oracle-l mailing list
> Subject: OCR / VD external vs. normal redundancy using NFS.
> Hello everyone,
> I'd like to know how does each of us configure redundancy for both the
> Grid Infrastructure's Oracle Cluster Registry (OCR) and Voting disks
> (VD) when they're stored over NFSv3 on an enterprise grade storage
> array with RAID disks. Do you use external or normal redundancy for
> OCR and VD?
> I'm looking to install Grid Infrastructure 11gR2 on RedHat Enterprise
> Linux 5 x86_64 over NFSv3 on a clustered Sun/Oracle Unified Storage
> 7410. The storage array has built-in redundancy on every components.
> Each cluster node has two quad-ethernet network interface cards (NIC).
> All network interfaces are built with two ports, one on each NIC, to
> create a private (bond0), public (bond1) and storage (bond2)
> interface. There are two redundant GbE switches dedicated for a
> storage-only non-routable subnet.
> Quick note, I'm not using ASM over iSCSI for various reasons. Mostly
> because every paper I read from NetApp/Sun/Oracle/EMC says the
> performance of ASM with software initiator iSCSI is not as good as
> NFS. Also because it's easier to manage the storage array's total disk
> space when using NFS instead of iSCSI. I'm also not using Oracle's
> dNFS feature simply because I haven't had the time to look at it and
> I've been working with NFS for over 10 years. Plus I'm also lucky (?)
> enough to be the UNIX sysadmin, the storage array administrator and
> the DBA, so I don't need to configure everything from the Oracle
> stand-point (i.e. I can't do finger pointing in case things go wrong,
> I'm the only one to blame).
> With that in mind, which option would you choose and why?
> Option A)
> Create an NFS share for OCR and another one for VD then use external
> redundancy. That would generate the following mount points:
> OCR = /u01/ocr/cluster.registry
> VD = /u01/vd/voting.disk
> -or-
> Option B)
> Create three different NFS shares for OCR and three other shares for
> VD then use normal redundancy. That would create the following mount
> points:
> OCR 1 = /u01/ocr/ocr1/cluster.registry
> OCR 2 = /u02/ocr/ocr2/cluster.registry
> OCR 3 = /u03/ocr/ocr3/cluster.registry
> VD 1 = /u01/vd/vd1/voting.disk
> VD 2 = /u02/vd/vd2/voting.disk
> VD 3 = /u03/vd/vd3/voting.disk
> Of course there are other options and variations. I welcome all
> comments and critics on that setup :)
> Many thanks,
> David
> --
> David Robillard, UNIX team leader and Oracle DBA
> --

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