StorageTek 6 manual I/O Considerations, Reconfiguration, Condition, Number of I/Os

Reconfiguration

(including all commands used when automated mounts or dismounts are necessary) need to be issued after the LSMs are brought online.

Note: ALL new control data sets (primary, secondary, and standby) must conform to the library hardware.

I/O Considerations

Reconfiguration is I/O intensive. For this reason, it is highly recommended that you reduce the number of scratch volumes as much as possible to shorten reconfiguration time. Refer to “Minimizing I/O Time” on page 270 for more information. The following table details I/O requirements for various situations.

Table 13. I/O Requirements

Condition:	Number of I/Os:
For every volume in the old CDS that remains in the	5
new CDS (volumes remain if their home panels have
not been changed)
For every scratch volume in the old CDS that remains	38-58 additional
in the new CDS
For every errant volume in the old configuration that	11 additional
remains in the new configuration
For every cell in the old configuration that remains in	1 additional
the new configuration
For every panel in the old configuration that remains	5 additional
in the new configuration

Note: Shadowing is disabled during the reconfiguration process. If a new secondary CDS is used, the final step of reconfiguration copies the new primary to the new secondary.

The quantities shown above represent most of the I/O done by reconfiguration. Depending on the ratio of cells to volumes, and nonscratch to scratch volumes, the number of scratch volumes can easily be the prime determinant of the number of I/O operations performed by Reconfiguration.

Chapter 4. Utility Functions 269

1st ed., 6/30/04 - 312579601