Number of Tape Volumes for Archive (ON-Archive and ontape) 

The number of volumes required in a volume set for Informix database archive with ON-Archive or ontape depends on:

The amount of data you need to archive determines how many volumes you require for a single archive.

For example, how often you archive and at what level influence how many volumes you require.

The longer you keep your tapes before overwriting them, the more volumes you require. The recommended period is 28 days or longer.

If you use ON-Archive , to find out how to set the period after which your tapes can be overwritten with new archive data, see the parameter EXPIRY_DATE in Editing the File oper_deflt.arc for ON-Archive.

The following examples illustrate the number of tape volumes required for archiving a normal and a large database:

Assume you want to archive at level-0 (full) daily during the working week (Monday to Friday). This requires two tape volumes per archive.

Assume you want to have a four week (28-day) cycle (that is, the tapes are reused after this period).

Then you need:

2 volumes per day x 5 days per week x 4 weeks = 40 volumes

Assume you want to archive at level-1 (incremental) daily during the working week (Monday to Friday). This requires two tape volumes per archive. Also assume that you want to archive at level-0 (full) once a week on the weekend and this requires four volumes per archive

Assume you want to have an eight week (56-day) cycle (that is, the tapes are reused after this period).

Then you need:

Level-1 archives: 2 volumes per day x 5 days per week x 8 weeks = 80 volumes

Level-0 archives: 4 volumes per week x 8 weeks = 32 volumes

Therefore, you need 112 volumes in total.