Path: utzoo!attcan!uunet!lll-winken!csd4.milw.wisc.edu!leah!rpi!batcomputer!cornell!uw-beaver!rice!sun-spots-request
From: matt@srs.uucp
Newsgroups: comp.sys.sun
Subject: more disk buffers under 3.x?
Keywords: SunOS
Message-ID: <8905172103.AA08274@flash.srs.com>
Date: 17 May 89 21:03:16 GMT
Sender: usenet@rice.edu
Organization: Sun-Spots
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Approved: Sun-Spots@rice.edu
X-Sun-Spots-Digest: Volume 7, Issue 299, message 9 of 13

Some time ago, someone posted a note describing the procedure for
increasing the number of disk buffers for a machine running 3.2.
Unfortunately, I don't have the name of that person handy, but perhaps
that's for the best as it turns out that the method given doesn't work.
Here is the relevant excerpt from the original note:

    On your running system: (This examples changes the value to 700.)
    We were running 3.2 on a Sun 4.

    adb -w /vmunix
    nbuf?W 2bc                      (which is 700 decimal)

    Now re-boot.

    Checked with:

    adb -k /vmunix /dev/mem
    nbuf?D  (shows in decimal what this is in /vmunix)
    nbuf/D  (shows in decimal what this is in /dev/mem)

    (Note: This value also shows up when you boot.)

Unfortunately, it doesn't work.  Although the nbuf variable does take
on the intended value, the actual number of allocated buffers doesn't
change.  To wit:

Before:
    using 95 buffers containing 778240 bytes of main memory

After:
    using 592 buffers containing 778240 bytes of main memory


Those are some pretty damn small buffers!  Does anyone know a way to make
this REALLY work (and DON'T say "yeah, upgrade to 4.0" and use the dynamic
buffer allocation)?  My server is sitting here with 8Mb of memory, only
3Mb of which have a chance of being used (that is the typical VIRTUAL
memory usage of the server).  Any help would be greatly appreciated.


P.S. And why did Sun tell us, three years ago, to have lots of memory
     in our server?  And don't tell me that our sales rep. knew about
     the memory usage semantics of 4.0!

-----
Matt Goheen	"waiting for 4.1.193"
uucp:		{rutgers,ames}!rochester!srs!matt
internet:	matt%srs.uucp@harvard.harvard.edu, matt@srs.uucp