1. Administrator's Guide
  2. Library Partitioning
  3. CAP Behavior

CAP Behavior

This section discusses CAP behavior.

Partitioned Library

WARNING:

All ACSs must have one CAP that is dedicated or is shared. Because all of the CAPs in an SL3000 can be dedicated to other partitions, this is a crucial restriction when configuring SL3000 partitions.

Dedicating a CAP in a Partitioned Library

With an SL3000 library, a CAP can be dedicated to a partition. When CAPs are dedicated to a partition, ACSLS can set these CAPs to automatic mode.

Sharing CAPs in a Partitioned Library

In an SL8500 library with legacy partitioning, CAPs are always shared among all partitions.

In a partitioned SL3000, or SL8500 with enhanced partitioning, library CAPs can be shared between partitions. The process is as follows:

  1. When a host uses a CAP to enter or eject cartridges, it reserves the CAP for its exclusive use.
  2. The host must complete the enter or eject and leave the CAP empty and closed.

    If you must terminate an enter on either of the following:

    • ACSLS - the canceled enter command must be issued

    • HSC - the drain command must be issued

  3. The CAP is now available for use by any partition in the library.

When Another Host Needs the CAP

If a host does not complete the enter or eject, the CAP may still contain cartridges for the affected partition. The CAP is still in a reserved status. This causes problems when other partitions need to use the CAP. To resolve this, the library must identity the host holding the reserve and terminate the enter or eject from that host.

In rare cases, you may not be able to access the host holding the reservation, either because the host crashed and cannot be restarted, or you lack physical access or the security authority to issue the commands needed. In these cases, the CAP reservation can be overridden using the SL Console.

Caution:

Overriding a CAP reservation using the SL Console should be done only as a last resort.

Assigning CAP Priorities for Shared CAPs

ACSLS can manage multiple partitions in the same library, and these partitions can share the same CAP(s). Audit ejects all cartridges with a duplicate and unreadable vol_id. When you audit multiple partitions (ACSs) at the same time, the audits may try to use the same shared CAP to eject the cartridges. The first audit reserves the CAP and the other audits are unable to reserve the CAP. The later audits are then unable to eject the cartridges.

To prevent this from happening, set the CAP priorities so different shared CAPs are the highest priority CAP in the different partitions. For example, if partitions 2 and 3 in an SL3000 are sharing CAPs 5 and 6, set CAP 5 as the highest priority CAP in partition 2 and CAP 6 as the highest priority CAP in partition 3.

Reserving the CAP

Consider the following when reserving the CAP:

  • When a CAP is in use for an enter or eject operation, all 39 slots (SL8500) and 26 slots (SL3000) are reserved for that operation. The CAP cannot be subdivided.

  • For addressing purposes, the CAP needs a location (ACS,LSM,CAP#). The LSM number is associated with the second rail in each library. For example: ACS#,1,0 for CAP A and ACS#,1,1 for CAP B

  • Reserving the CAP

    The CAP is a common component among partitions. Each host will:

    • reserve the CAP to use it for an enter or eject.

    • release the CAP when the enter or eject is terminated. Another host can then use it.

Terminating a CAP Reservation

  1. When ACSLS finds that a CAP is reserved by another partition, it reports the partition ID and host ID holding the reservation.

    Contact the host owning the reserved CAP and request for them to complete the enter or eject.

    Once this is done, the empty CAP is then unreserved and available.

  2. If the CAP reservation cannot be released by the host holding it, the SL Console (SLC) command overrides the CAP reservation.
    1. The SLC command displays a warning to the host informing it that the reservation from the specific partition owner will be removed.
    2. The SL Console queries the CAP to find the partition owner/requester/reserver.
    3. The SLC displays the partition name (HLI1, HLI2, HLI3, HLI4, or Default) in the warning.
  3. The library sends a CAP Overridden Message to the host that held the reservation.

    This host should terminate the enter or eject task that was in progress.

  4. The library now owns the CAP.

    The CAP must be empty and closed before it is available to be used by another host. If the:

    • CAP has cartridges in it, you must empty the CAP before a partition can use it using the SL Console.

    • CAP is open, you must empty and close it. The library can then audit it and ensure that it is empty. Until the CAP is closed, it cannot be made available to any partitions.

    • CAP is empty, it will be locked and available to be reserved by any partition.

  5. The CAP is now unreserved and is available for use by any partition.