StorageTek 6 manual Defining Planned ACSs with no Stations

that are not directly affected. Then, these subsystems can be recycled (brought down and then restarted) to pick up the changed information. Cycling the affected HSCs can be done at a convenient time, with only one HSC down at a time. This permits an HSC server to remain up, servicing requests from clients.

Note: In many instances, the SET utility can run while HSC subsystem(s) are active. However, some SET options require that the HSC(s) affected must be down, e.g.,

SET HOSTID.

In most cases, the LSM and/or ACS affected must remain offline until HSCs on affected hosts are recycled, e.g., when deleting or changing drive unit addresses with

SET SLIDRIVS.

In most cases, all affected HSCs must be recycled to reinitialize and support the new configuration. Refer to “SET Utility” on page 392 for restrictions on the specific SET options and processes to follow when making configuration changes.

Defining a New Configuration to Avoid Future Reconfigurations

When you define a new configuration with LIBGEN, you can add some flexibility to avoid running reconfigurations in the future.

•If additional hosts may be added later, define dummy host IDs now. Entries for future hosts can be defined in the SLILIBRY macro, HOSTID=(host0,...,host15) parameter. For example, host IDs of FREE1, FREE2, and FREE3 could be defined. Then, the SET utility HOSTID option can be used to change these ‘‘reserved’’ host IDs to the new ones being added to the configuration.

SET HOSTID(newhost),FORHOST(FREE1)

•When a CDS is created, it is desirable to allocate more then the minimum amount of space. The free blocks can be used later when additional drives are added.

Defining Planned ACSs with no Stations

The HSC allows users to define an ACS without specifying station addresses (refer to the SLIACS macro in the HSC Configuration Guide).

Using this feature means that a planned ACS can be placed into the LIBGEN/SLICREAT process and remain disconnected without generating message SLS1664A (‘‘ACS AA is disconnected’’) or requiring the user to enter the OPTion DISCmsg command to suppress SLS1664A.

If planned ACSs have been defined previously with dummy station addresses, these stations can be removed using the SET SLISTATN utility. In this case, the user does not specify any output stations. Refer to “SET LMU Station Address Numbers” on page 408 for more details.

When the planned ACS becomes available, SET SLISTATN can be used to add stations for the ACS. The ACS can then be brought online without recycling the HSC.

Chapter 2. Host Software Component Functions 51

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