SAP Note 24237 - arcauto: Log file backup only on separate volumes

Symptom:

When backing up log files with the "arcauto" script, all backups are written to separate volumes.

Cause and prerequisites

These settings were consciously made in such a way to simplify tape handling (for example, one tape per day).

Solution

If the tape is to be changed only when it is full, "/APART" is to be changed to "/NOAPART" in the "arcauto" script (lines 117-119).
The tape then is written up to its end.

In every case, however, make sure that the tape is changed before the expiry date of the requests in the OnArchive Catalog: after this date the Request IDs are used again and having identical IDs on one tape can ruin the restoring the backup.
If you would like to set a tape explicitly to "full," so that a new volume is used for the next backup (for example, daily cron job), you should proceed as follows:

1. Determine the volume label which is to be characterized as "full" (next volume to be used): arcauto -v -d

2. Execute the following statement in the database sysmaster where the value 1 must be used for . update arc_volume
set vol_full = 'Y'
where vset_name = ''
and vol_lable = ''
and vol_vid = (select vset_vid
from arc_vset
where vset_name = 'VSet>');

Caution: Since "Labels" can be assigned more than once during volume definition, all such volumes are marked as full.

Note: When saving with 'onautovop', every tape is taken which belongs to the correct Vset and is marked as 'Free' in the OnArchive tape administration!

We recommend this procedure especially when a separate tape is used for saving the log backup files on each day of the month (e.g., definition of 31 volumes, Expiry Date = 28). In this case, a new tape can be used for each day of the month and the request runs out after 28 days. This means that a free tape will always be available.

The disadvantage of this type of backup strategy is that tapes need to be changed frequently and in case of a log. restore, need to be changed just as frequently. In addition, the arcauto -d option can be used only with limitations, since all free tapes are displayed in descending order here. If this solution in used in conjunction with the day of the month, be attentive only to the day of the month to determine the correct tape: the arcauto -d option must not be used.