We had enabled the checkpoint improvement code on 6.0 after receiving notice
on the list in February.   Unfortunately, this setting caused a system
crash.   We were advised by HP to disable this feature after that occurred.


Tom Genute



                -----Original Message-----
                From:   Ken Paul [mailto:[log in to unmask]]
                Sent:   Friday, May 26, 2000 7:58 PM
                To:     [log in to unmask]
                Subject:        [HP3000-L] Reminder for ALL MPE/iX 6.0 Users

                Just a reminder to all of you who are already on MPE/iX 6.0
or are thinking
                of upgrading to 6.0.

                This doesn't include anyone on 5.5 or 6.5, only MPE/iX 6.0
with no PP, PP1
                or PP2.

                I sent a message to the list back in late February about a
potential problem
                with 6.0 and a possible fix available within VOLUTIL.  Since
that time we
                have repaired a lot of IMAGE databases on 6.0 machines which
possibly could
                have benefitted from this new VOLUTIL feature.  As the old
saying goes: "an
                ounce of prevention...."

                Here is the important part of my message from February:

                >While attending SigSoftVend last week I was talking to a
CSY lab engineer
                >and mentioned these 2 occurrences.  He wondered whether
both clients were on
                >6.0.  Long story short, he believes that there is a corner
case bug within
                >the new XM code for 6.0 which he is now going to develop a
patch.  Until
                >that patch becomes available, he mentioned that users of
6.0 could utilize a
                >new feature on 6.0 (and only 6.0) within the XM which would
prevent the
                >problem from happening.
                >
                >In the 6.0 Communicator on page 216 there is an article on
Transaction
                >Manager.  On page 219 within the article there is a section
entitled
                >Checkpoint Improvement which describes 2 new commands in
Volutil for showing
                >and setting this new feature.
                >
                >In checking the last years worth of messages on 3000-l
there have been a few
                >references to this option. Mike Hornsby asked about it in
February of 1999
                >and Steve Macsisak with HP had a good description of it on
February 19th
                >1999.  Carl McNamee mentioned it favorably back in November
of 1999.
                >
                >By default this option is disabled when you install 6.0 and
if you enable it
                >for your volume sets then you should not experience the
problem mentioned
                >above and you may even see a performance improvement on
Checkpoints within
                >the XM.  The 2 commands are:
                >
                >showchkptstat <volset-name>
                >
                >alterchkptstat <volset-name> ENABLE|DISABLE
                >
                >A key paragraph on page 220 then states:
                >
                >"Since this solution remembers the dirty page ranges in a
data structure
                >associated with each open file, it can't affect files that
were open before
                >giving this request (ENABLE).  However, it will come into
effect for the
                >files that were open (for the first time) after giving the
request.  So the
                >best way to enable or disable the Checkpoint Improvement is
to reboot the
                >machine after giving the command."
                >

                Hope this helps,

                +---------------+
                |               |
                |            r  |  Ken
[log in to unmask]
                |          e    |
http://www.adager.com
                |        g      |  Ken Paul                      Tel 208
726-9100
                |      a        |  Customer Support              Fax 208
726-2822
                |    d          |  Adager Corporation
                |  A            |  Sun Valley, Idaho 83353-3000
U.S.A.
                |               |
                +---------------+