Re: Why I don't like ASM

From: Justin Mungal <justin_at_n0de.ws>
Date: Fri, 24 Jan 2014 00:17:43 -0600
Message-ID: <CAO9=aUzdu_y5wfRF+J6sNU83o+j87HokZ+yv=NCn_rCBuHdXwQ_at_mail.gmail.com>

Where I'm at the majority of ASM installs are on RAC. We have some stand-alone systems using ASM but that is generally because the customer wanted it. Like anything else there are benefits and drawbacks.

The biggest drawback that I can think of is, as you said, added complexities and dependencies. Patching, especially, becomes more complicated.

From an advantages perspective, I find that using ASM along with enterprise hardware can give you added flexibility. For instance, if a customer needs to migrate to faster spindles you can present the new LUNs to the nodes/server, and then add them to the diskgroup and drop the old LUNs seamlessly. I also like that it can all be managed from the Oracle tool-set, which means you'll have a generally similar experience across platforms. From what I've read there's also less I/O overhead when comparing ASM to a filesystem, but I'm sure that's arguable and would depend on the file system being used.

On Thu, Jan 23, 2014 at 9:13 PM, Dave Morgan <oracle_at_1001111.com> wrote:

> Because it adds complexities and dependencies.
>
> Don't get me wrong, when I was a junior the primary job of the
> intermediates was to manage
> 200 x 2GB, 15K rpm JBOD. Redo and archive logs had to be on separate
> "everything".
> Hot spots due to file access and file sizes were huge limitations.
>
> And where was ASM .................. in the future
>
> Now, a basic install is 3 mount points of 500GB, on 3 different arrays.
> - 1 for data (preferably SSD)
> - 2 for redo, archive, backups and work space
> The 2 biggest physical limitations, file size and hot spots disappear.
>
> So, why is it common for me to come across database installs using ASM in
> the above scenario?
> What is the benefit from using ASM in the above scenario?
>
> What I'm really looking for is appropriate use cases for ASM.
>
> One of them, I believe, having done both, is:
> ASM is easier than managing raw disk, therefore RAC installs should use
> ASM.
>
> Is the above true? What about ASM vs Veritas? Other shared disk managers?
>
> Opinions are welcome, opinions backed by data and scripts are valued :)
>
> Dave
> --
> Dave Morgan
> Senior Consultant, 1001111 Alberta Limited
> dave.morgan_at_1001111.com
> 403 399 2442
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

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Received on Fri Jan 24 2014 - 07:17:43 CET