VSM - Chain Breaking Values per Microcode level

Asset ID:	1-71-1451050.1
Update Date:	2012-07-03
Keywords:

Solution Type Technical Instruction Sure

Solution 1451050.1 : VSM - Chain Breaking Values per Microcode level

Applies to:

Sun StorageTek VSM System - Version 4 to 5C [Release 4.0 to 5.0]
Information in this document applies to any platform.

Goal

This document shows the values set per VSM microcode for chain breaking, also called Sync Sort changes.

Fix

Values are used in an attempt to stop one application from acquiring then maintaining control of one of the interfaces in the VTSS. This is accomplished by forcing the program to terminate its command chaining sequence thus allowing another application to use the interface.

D02.04 : wrt chain break = 15ms for first then every 5ms
rd chain break = no break

D02.05 : wrt chain break = 15ms then every 5ms
rd chain break = none

D02.06 : wrt chain break = 25ms for first then every 25ms
rd chain break = no break

D02.07 : wrt chain break = 15ms for first then every 5ms
rd chain break = no break

D02.08 : wrt chain break = 15ms for first then every 5ms
rd chain break = no break

D02.09 : wrt chain break = 15ms for first then every 5ms
rd chain break = add break at 15ms

ZD2.09.11.00 : wrt chain break = 25ms for first then every 25ms
rd chain break = every 25ms Best strategy if customers wants sync sort to run best by sacrificing run time of other applications.

D02.10 : wrt chain break = 15ms for first then every 5ms
rd chain break = break at 15ms

ZD2.10.11.00 : wrt chain break = 15ms for first then every 5ms
rd chain break = break at 15ms

D02.11 : wrt chain break = 15ms for first then every 5ms
rd chain break = break at 15ms

D02.12: wrt chain break = 15ms for first then every 5ms
rd chain break = break at 15ms

D02.14 : Chain Break Option from DOP - this feature, primarily for the VSM4(but not limited to), provides the ability to modify the command chain breaking algorithm dynamically thru the DOP Configuration screen.

There are three chain break settings - HIGH. MEDIUM, and LOW.

The HIGH setting is the default and will break long command chains more frequently allowing shorter chain jobs a better chance to run.

The MEDIUM setting forces a balanced chain break that does not favor long or short chain jobs.

The LOW setting breaks the chain least frequently allowing the jobs like SyncSort and DB2 to run at their max rate without being interrupted.

Changing the break setting is immediate and does not require any other action.

4-25-2011- BF – Created

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