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Sometimes, ideas that sound funny come from what I call "the lost
parameter." It's like the story at http://www.wowzone.com/5monkeys.htm.
One really good reason not to keep a disk full is that if a disk receives so many I/O requests per second that performance suffers, then one way to fix it is to move bytes off that disk to make it "less interesting" to so many users.
But if someone forgets why they moved bytes off a disk once upon a time, then it begins to look like a rule saying you should never keep a disk more than x% full.
Another reason to keep a disk partly empty is to ensure that the OS file extent manager has some space to work in. But if you're using a disk solely for Oracle data files that don't often grow or shrink, then you don't need to leave the elbow room.
Of course, the SA could have some perfectly legitimate reason that I've never heard of. To quote Deborah Holland, "Talking is good."
Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
Nullius in verba
Hotsos Symposium 2007 / March 4-8 / Dallas Visit www.hotsos.com for curriculum and schedule details...
-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Mercadante, Thomas F
(LABOR)
Sent: Tuesday, June 06, 2006 7:13 AM
To: fred_fred_1_at_hotmail.com; oracle-l_at_freelists.org
Subject: RE: High disk capacity dangers
I'd be curious to know what number he feels is "ok". 90%? And why?
-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Fred Smith
Sent: Tuesday, June 06, 2006 8:05 AM
To: oracle-l_at_freelists.org
Subject: High disk capacity dangers
Just wanted to run this by everyone here, I have a 9.2.0.6 database on
HP-UX. Some of my read only tablespaces are on a physical disk that I
keep
at about 99% capacity (it's not going to grow obviously, it's
read-only).
The new Unix SA is saying that it's unacceptable and dangerous to keep a
disk at 98,99, or 100% capacity. I always thought it could be even at
100%
capacity without any problems.
Is there any reason that anyone knows of as to why a disk should not be
at
99% or 100% capacity?
Thank you!
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Received on Tue Jun 06 2006 - 07:39:03 CDT