SUMMARY:buffers

From: Banzon, Arnel <abanzon_at_optimark.com>
Date: Mon, 19 Apr 1999 10:00:10 -0400

Thanks to everyone that reply.

Original Question was:

Can anyone help me what parameter is used to adjust the buffers underlined
below.

Digital UNIX V4.0D (Rev. 878); Thu Jan 7 17:20:22 EST 1999
Jan 7 17:22:29 siac1 vmunix: physical memory = 512.00 megabytes.
Jan 7 17:22:29 siac1 vmunix: available memory = 490.64 megabytes.
Jan 7 17:22:29 siac1 vmunix: using 975 buffers containing 7.61 megabytes of
memory


Responses:

Hi Arnel:

        Sure: Do a "sysconfig -q vfs" (this queries your "Virtual Filesystem
kernel subsystem) and you'll see a thing called a "bufcache" listed. This is
the cache that holds meta-data for UFS file-systems; note *not* AdVFS
filesystems. You can adjust this easily by invoking the "dxkerneltuner" --
the graphical kernel-parameter adjuster -- and upping or lowering this value.
The default value is "3%".

Best Regards,

Mark Ray
UNIX Administrator
S & S Worldwide
Colchester, CT

Append the following to your /etc/sysconfigtab and reboot:

vfs:
        bufcache = 1

This will set the cache to 1% of the memory size. The cache is used
for the UFS filesystem. If you are running AdvFS you can make it
very small as it is only needed for UFS CDROMs, I think. I have
not tried setting it to 0 though.

Hope this helps // Tom

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You could try modifying the value for bufcache in the vfs subsystem. The
value is a percentage, normally at 3% on most systems. This is the file
system metadata cache.
Raviprasad
It is the "bufcache" parameter in your kernel configuration,
which is expressed in units of percent of physical memory.  The
default is 3.
Why?  What do you hope to gain by changing it?
	I think it is "bufcache".  It works out on a system I have
	which has it set to 3% and is using 19 MB on a 640 MB system.
	Digital UNIX uses a unified buffer cache, which gives the
	file system cache access to all of free memory, not just
	the small amount indicated in the "using xxx buffers" line.
	There are other parameters that control the minimum and
	maximum amounts that the UBC will use.

Received on Mon Apr 19 1999 - 14:02:57 NZST