Sun StorageTek SL3000 Modular Library System
 
Sun StorageTek Auto Cartridge Sys Lib SW (ACSLS)
 

PLA-Support>Sun Systems>TAPE>Tape Hardware>SN-TP: SL3000-8500 Library
 

In this Document

Symptoms

Cause

Solution

Applies to:

Symptoms

 SL3000 only ejects a maximum of 42 tapes at a time, even though the library has AEMs.

Cause

 Current limitations of ACSLS.

Solution

This is the limitation in ACSLS as to the number of volsers that can be passed into an eject command.

The specific value of "42" is not only related to the maximum cartridges that can be ejected at a time by an eject command by ACSLS.

This value of "42" is a limitation for any ACSLS command for which you can specify more that one identifier of a certain type.

As an example, a QUERY command encounters such limitation.
If you want to query more than one drive, you will be limited to 42 entries in your command, which the syntax would be:
     query drive drive_id_1 drive_id_2 drive_id_3 ... drive_id_41 drive_id_42
(by experience, you will do quicker by issuing a "query drive all" command)

For eject commands, you are limited to 42 identifiers, which means 42 cartridges if each identifier correspond to 1 volser, but which can become many more cartridges if you use volranges instead of volume_ids as identifiers.

In early versions of ACSLS, this limitation was 21 ... which also correspond to the size of the legacy CAP of a 4410.
With the introduction of bigger CAPs (Clipper CAP), engineering just doubled this limiting value from 21 to 42, to match such big CAPs.

This "42" limitation was never a big problem with any kind of libraries, up to the SL8500 with a CAP of 39 slots, as there were workarounds to limit the eject command to match the size of the CAP.
This is how the "ejecting.sh" utility is working, as it will split a long list of volsers provided in smaller entries consisting of several "CAP size" lists of volsers.

So this limitation really only affect ejection of cartridges when you want to use the AEM of a SL3000.
The ACSLS admin guide even mention the following in the "ejecting.sh" utility description page:

     Note – A maximum of 42 cartridges can be ejected to the CAP in a single eject command. Thus, only 42 cartridges are ejected to an SL3000 AEM at a time.

In the ACSLS admin guide, there is a small section called "Bulk ejects". Here is what they say:
     You can eject up to 42 cartridges at a time when you use vol_ids in the eject command.
     When specifying volumeranges using the cmd_proc or the ACSAPI xeject command, you can eject up to 42 volumeranges in a single eject. By specifying volumeranges you can eject many cartridges at a time.

Above info is provided by: Christophe LEROY | Senior ACSLS, SamQFS & SL150 Support Specialist
Support Engineer Global Systems Technology Service Center Tape Domain

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