My local Compaq people have got onto this one quicker than the list. Nice
change :-)
Thanks to Jeremy Hibberd for the following
----------------------------------------------------------------------------
------------------------------
...
(vm_perform_v40dbl11) which fixes a virtual memory problem in DU 4.0D -
looks like the same patch. Apparently it's included in pk#4 or BL12.
BLITZ TITLE: DIGITAL UNIX V4.0D/E VM PERFORMANCE PATCH
BACKGROUND: ..... re problem reports involving degraded
system performance on systems which were operating
in the low available virtual memory range. Generally,
these systems were running many application processes,
each requiring large virtual memory resource. Systems
which are running SAP and large databases may experience
this problem.
PROBLEM: .... carefully analyzed these problem reports and
determined that some improvement could be achieved
in the manner in which the operating system was
managing VM resources (e.g., page swapping) for systems
operating near the lower limit of available virtual memory.
RESOLUTION:
.... developed a patch to resolve this problem
for DIGITAL UNIX systems which are running DUNIX Versions 4.0D
and V4.0E. For V4.0D systems, patch kit 3 - BL 11 must be installed
before installing this new VM performance patch.
The SAP reference for this problem is as follows
________________________________________________________________________
Number 0136653
Version 0003 from 12.07.1999
Status Released for customer
Set by SAP AG on 12.07.1999
Language EN
Short text Performance problems on Digital UNIX 4.0D and 4.0E
Administrator SAP AG
Component BC-OP-CPQ Compaq Unix
__________________________________________________________________
Long text
Symptom
The performance is bad (up to operating system shuts down) for Digital
UNIX 4.0D or 4.0E under a high system load.
An early symptom is a drastically increased number of swapping
activities.
On the operating system, apparently no more processes can be started
(process start times of more than one minute), in which case currently
running processes whose process pages are not yet removed, are not
affected.
Additional key words
virtual memory problem
low free memory
heavy pagine/swapping activity
Cause and preconditions
For Digital UNIX, 4.0D (up to and including PatchKit 3) and 4.0E
(without PatchKit) it can happen that the system performance suffers
massively if the system load is increased by the R/3 System. This can
result in an operating system shutdown/crash.
The problem only occurs if the R/3 buffers are configured so that they
exceed the physically available memory (this is legal and is, for
example, set by EarlyWatch).
As a result, a memory bottleneck can occur in the operating system
which
the system tries to prevent with paging/swapping.
The bug fix entered under "Solution" should be implemented as a
preventative measure in the above-mentioned operating system versions.
CAUTION:
Not **all** performance problems can be solved this way!
The problem discussed here only refers to Digital UNIX 4.0D
and 4.0E together with the specified accompanying circumstances!
Solution
Digital/Compaq has a bug fix for this problem.
This bug fix is not publicly available but should be installed on your
affected systems by your responsible Compaq service.
This bug fix was made known at Compaq by a "Blitz" from 12/24/1998. The
"Blitz" title is
"DIGITAL UNIX V4.0D/E VM PERFORMANCE PATCH"
Source code corrections
______________________________________________________________________
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Received on Tue Sep 28 1999 - 06:24:26 NZST