From: Bill Verzal (BVerzal@KOMATSUNA.COM)
Date: Tue Jan 13 2004 - 10:22:52 EST
I've told him that even shortly after a freshly booted system, after all
apps start, that memory is already fragmented.
I agree with your statement about the snapshot. I felt the same way.
There is no constraint issue - just an excuse for reboots because "it is a
good idea".
At the risk of starting a war about reboots, I'll bow out.
BV
--------------------------------------------------------
"If everything is coming your way, then you are in the wrong lane"
Bill Verzal
AIX Administrator, Komatsu America
(847) 970-3726 - direct
(847) 970-4184 - fax
"Hunter, Mark"
<Mark.Hunter@ANHE
USER-BUSCH.COM> To
Sent by: IBM AIX aix-l@Princeton.EDU
Discussion List cc
<aix-l@Princeton.
EDU> Subject
Re: "Fragmented memory"
01/13/2004 09:15
AM
Please respond to
IBM AIX
Discussion List
<aix-l@Princeton.
EDU>
Doesn't really apply with virtual memory. No memory is specifically
allocated
permanently for a specific purpose, except some of the kernel. A
"snapshot" of
memory isn't really that useful. Memory gets loaded and reloaded a lot -
see
the paging algorithm.
Even on a "fresh" system, you are not guarenteed contigous memory
allocation.
If you think, for some reason, you are having memory constraint issues, I
would
look at /usr/samples/kernel/vmtune. Changing min{perm/client} and
max{perm/client} are more likely to help than a reboot would.
We run with 10/40 min/max perm on non database boxes and 5/20 min/max on
database boxes.
Mark Hunter
-----Original Message-----
From: Bill Verzal [mailto:BVerzal@KOMATSUNA.COM]
Sent: Tuesday, January 13, 2004 8:58 AM
To: aix-l@Princeton.EDU
Subject: "Fragmented memory"
That is what my boss says is the reason we reboot every so often. Because
the memory is fragmented.
I personally don't buy it. Although it may be true, I don't think there is
a performance hit because of it.
Does anyone know any command equivalent to the DOS "mem /d" that will show
me what chunks of VM are allocated to what programs, and what areas are
free ?
BV
--------------------------------------------------------
"If everything is coming your way, then you are in the wrong lane"
Bill Verzal
AIX Administrator, Komatsu America
(847) 970-3726 - direct
(847) 970-4184 - fax
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