Scott,

We use Image logging on a large scale on our 996-500.  We currently define
twelve (12) log ID's, with the most heavily used process approaching 700
users.  We originally implemented logging for roll-forward recovery back in
the '80's, and we used it quite frequently after head crashes on the 7933's
in use at that time.  Admittedly, we have not had an occasion to recover a
database due to a disk failure after we migrated production to the 996 (was
a 992, originally) and implemented exclusive use of RAID-3 arrays on that
system.  We enable Rollback Recovery now, but interestingly (at least to
me) we have never had incomplete transactions backed out in the few times
we've had system failures and attempted to recover the databases.  We were
later advised that XM was probably responsible.

Aside from the recovery issue, we often do extensive auditing of selected
log files for security purposes or tracking selected transactions.  We use
Bradmark's DBAudit tool for this purpose.  We've also been able to recover
and repost accidentally deleted transactions using DBAudit and SUPRTOOL --
in a couple of cases, this amounted to several thousand deletes due to
errant batch programs.

From a performance perspective, I'm not certain that having the user
logging subsystem in CM has been a hindrance.  During performance audits, I
don't think I've ever seen a user logging process ever display as an
'interesting' transaction.

It's conceivable that we could see significant growth in the use of our
application over the next few years, and I, for one, would hate to think of
running into the 1140 users per process limit.

Lee Gunter          [log in to unmask]
Regence Blue Cross Blue Shield of Oregon / Regence HMO Oregon




From: [log in to unmask] on 07/02/98 08:29 PM

Please respond to [log in to unmask]


To:   [log in to unmask]
cc:    (bcc: Lee Gunter/BCBSO/TBG)
Subject:  Re: Number of processes which can open an IMAGE data base in mode
      1 ?




<Scott McClellan after others ... >

<deletia>

The investment required to move user logging to NM is pretty significant.
How many of you out there use user logging on very high end HP3000s?
Why? For recovery? Have you ever had to use the recovery feature on
MPE/iX?
Do you read the log files with your applications?
Please share any data that heps us understand either your present usage of
user/image logging, and/or your system growht.