Thin Provisioning and Operationalizing ASRU?

From: Adam Musch <ahmusch_at_gmail.com>
Date: Fri, 27 Sep 2013 11:33:11 -0500
Message-ID: <CAH4Zrrupf4ePrqicVfN_QrsukMMYDwH2S=PBxU3j1vqTJERh-g_at_mail.gmail.com>

My company is evaluating a thin provisioned storage array, and one of the issues we ran into is the need to run the ASM Reclamation Utility (asru) as we purge data, as we've isolated isolate date-ranged partitions to specific tablespaces to help optimize backups, as old tablespaces can be put into read-only mode.
Is anyone out there using ASRU on a day-to-day or month-to-month basis, and if so, how have you operationalized it, or have you?

We're using ASM with RAC; if we were using a file system, the thin provisioning reclamation against the array would happen automagically.

My concerns with the utility are multiple:

1. How safe is it to run this utility while the database is open and running? Do you do so as part of your normal purge operations?
2. Is free space internal to an ASM disk reclaimed? I can see from the trace files that it will zerofill space after it resizes the ASM disk down, but does it reorganize/compact the in-use stripes of the ASM disk prior to doing so? If the utility works functionally like resizing a datafile - i.e., only to the HWM - how much use is it?
3. How does one prevent, absent training and education, from preventing a manual or automatic rebalance or other administrative ASM disk operation from conflicting with ASRU?

Thanks very much for any input or other experiences you may have had with ASRU and thin provisioning with ASM disks, regardless of storage vendor.

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Adam Musch
ahmusch_at_gmail.com

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http://www.freelists.org/webpage/oracle-l Received on Fri Sep 27 2013 - 18:33:11 CEST