In <8FE5EA8B92FED11194D500805F312C19067C49 AT mxsjhb02.Transnet.co DOT za>, on
11/30/98
at 10:41 AM, Moodley Desigan * Datavia <DesiganM AT TRANSNET.CO DOT ZA> said:
>Hello list members,
>We're running ADSM server version 3.1.2.0 on MVS OS 390. We recently
>changed our recovery log mode from normal to roll forward. We set a
>database backup trigger of 20%. When the log reached 20%, a full database
>backup is triggered. This usually happens about every 24 hours. After the
>backup, the recovery log percentage dropped to about 1%. This continued for
>about 4 days. However, during the weekend, the recovery log percentage did
>not drop after a database backup causing database backups to be triggered
>immediately after a successful backup. Here is an extract of the job log:
>ANR4550I Full database backup (process 530) complete, 2666266 pages copied.
>ANR0985I Process 530 for DATABASE BACKUP running in the BACKGROUND
>completed
>ANR0985I with completion state SUCCESS at 07:51:23.
>ANR4556W Warning: the database backup operation did not free sufficient
>ANR4556W recovery log space to lower utilization below the database backup
>ANR4556W trigger. The recovery log size may need to be increased.
>We were eventually forced to bounce ADSM to get the recovery log back down
>to 0.1 %. Here is the recovery log status:
> Available Space (MB): 3,520
> Assigned Capacity (MB): 3,520
> Maximum Extension (MB): 0
> Maximum Reduction (MB): 3,484
> Page Size (bytes): 4,096
> Total Usable Pages: 900,608
> Used Pages: 8,420
> Pct Util: 0.9
> Max. Pct Util: 0.9
> Physical Volumes: 4
> Log Pool Pages: 512
> Log Pool Pct. Util: 0.11
> Log Pool Pct. Wait: 0.00
>Cumulative Consumption (MB): 125,835.95
>Consumption Reset Date/Time: 04/16/1998 09:07:19
>Here is our database status:
>Available Space (MB): 16,044
> Assigned Capacity (MB): 15,004
> Maximum Extension (MB): 1,040
> Maximum Reduction (MB): 4,588
> Page Size (bytes): 4,096
> Total Usable Pages: 3,841,024
> Used Pages: 2,666,346
> Pct Util: 69.4
> Max. Pct Util: 69.4
> Physical Volumes: 11
> Buffer Pool Pages: 8,192
> Total Buffer Requests: 10,998,632
> Cache Hit Pct.: 99.15
> Cache Wait Pct.: 0.00
> Backup in Progress?: No
> Type of Backup In Progress:
> Incrementals Since Last Full: 2
>Changed Since Last Backup (MB): 39.00
> Percentage Changed: 0.37
>Last Complete Backup Date/Time: 11/30/1998 08:34:27
>We are still running in roll forward mode. Can someone advise us as to
>whether we should keep going in roll forward mode or revert to normal mode.
>Also any advise as to how to manage roll forward mode will be appreciated.
>Thanks.
>Kind regards,
>Desigan Moodley
>* <mailto:DesiganM AT Transnet.co DOT za> DesiganM AT Transnet.co DOT za
I have had this problem a few times but I still use rollforward. The problem
is usually caused by a long running transaction or a hung session. This can
prevent the log from shrinking after the backup.
If you have an automation product like netview, key off the
ANR4556W message to bump up the logfull% to stop the
loop of backups. This may give the long backup time to complete.
You say that you trigger full backups, but your 'q db' says you have done 2
incrementals. How are you doing the incrementals?
--
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Bill Colwell
Bill Colwell
C. S. Draper Lab
Cambridge, Ma.
bcolwell AT draper DOT com
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