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Home -> Community -> Mailing Lists -> Oracle-L -> RE: I/O and db_file_multiblock_read_count
I have found that I/O requests that involve the same spindles more than
onec in a single
request simply do not perform. It is generally better to hit the LUN
more times for I/Os
sized rightly to not wrap an entire stripe set.
So, if I have 2 disks and intend to scan them with 1MB reads, uh, I
don't set the stripe
width to 32KB. Having the array line up 16 chucks on each disk to
satisfy a single
transfer request is just a mess.
In fact, I generally set stripe width to a value larger than 1MB if the kit supports it.
YMMV ... this is a religious topic you know... :-)
From: Vlad Sadilovskiy [mailto:vlovsky_at_gmail.com] Sent: Monday, December 11, 2006 1:29 PM To: kevinc_at_polyserve.com Cc: oracle-l Subject: Re: I/O and db_file_multiblock_read_count How does number of disk hits for larger I/O corresponds tonumber of hits for smaller I/O in respect to the whole process. It should not be more should it? Unless same data gets read twice.
-- http://www.freelists.org/webpage/oracle-lReceived on Mon Dec 11 2006 - 15:38:39 CST
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