Re: [PERFORM] SAN and full_page_writes

Thanks for pointing that out Bruce.

NetApp has a 6 page PDF about NetApp and databases.  On page 4:

As discussed above, reads and writes are unconditionally atomic to 64 KB. While reads or writes
may fail for a number of reasons (out of space, permissions, etc.), the failure is always atomic to
64 KB. All possible error conditions are fully evaluated prior to committing any updates or
returning any data to the database.

From the sound of it, I can turn of full_page_writes.

This document can be found at http://www.netapp.com/us/ by searching for hosting databases.

Thanks,

--Nik

On Sat, Sep 6, 2008 at 3:46 PM, Bruce Momjian <bruce@momjian.us> wrote:

Nikolas Everett wrote:
> I seem to have answered my own question.  I'm sending the answer to the list
> in case someone else has the same question one day.
>
> According to the NetApp documentation, it does protect me from partial page
> writes.  Thus, full_page_writes = off.

Just for clarification, the NetApp must guarantee that the entire 8k
gets to disk, not just one of the 512-byte blocks that disks use
internally.

--
 Bruce Momjian  <bruce@momjian.us>        http://momjian.us
 EnterpriseDB                             http://enterprisedb.com

 + If your life is a hard drive, Christ can be your backup. +