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Asset ID: 1-73-1000309.1
Update Date:2010-08-30
Keywords:

Solution Type  FAB (standard) Sure

Solution  1000309.1 :   A microcode bug exists in all V07+1 (50-07-51-00/00 and higher) microcode that in a limited number of configurations can cause all DKA MPs to blockade and recovery may be very disruptive.  


Related Items
  • Sun Storage 9990 System
  •  
  • Sun Storage 9985 System
  •  
Related Categories
  • GCS>Sun Microsystems>Sun FAB>Standard>Reactive
  •  

PreviouslyPublishedAs
200426


Product
Sun StorageTek 9990 System
Sun StorageTek 9985 System

Bug Id
None.


Impact

When a ShadowImage, etc., pair(s) is/are deleted, CHK3 and WCHK1 may occur in all DKAs causing all DKA MPs to be blocked.


Contributing Factors

Microcode Affected :

DKCMAIN 50-07-51-00/00 and later (all V07+1 versions)

Software Affected:

ShadowImage, ShadowImage for z/OS, Cross-system Copy, Volume Migration Compatible Mirroring for IBM FlashCopy, Compatible Mirroring for IBM FlashCopy Version2

This issue occurs when any of the Operations 1 through 7 are performed in a subsystem that satisfies Configurations 1 to 3 below.

[Configuration]
(1) ST9990 and ST9985 - DKCMAIN V07+1 50-07-51-00/00 and later
(2) The number of CUs is four or less
(3) In the Shared Memory Size Configuration panel, a check box of "Flash Copy V2/COW snapshot" is not selected

[Operation]
(1) Delete a ShadowImage pair
(2) Delete a ShadowImage for z/OS pair
(3) Delete a Cross-system Copy pair
(4) Perform Volume Migration from Storage Navigator
(5) Delete a Volume Migration pair
(6) Create a relationship of Compatible Mirroring for IBM FlashCopy for COPY MODE
(7) Delete a relationship of Compatible Mirroring for IBM FlashCopy


Root Cause

During the process of deleting a ShadowImage (or other PP) pair, the microcode checks to see if the related logical volume is used for Compatible Mirroring for IBM FlashCopy Version2.  The microcode unfortunately does not first validate that the SM for Compatible Mirroring for IBM FlashCopy Version2 is activated.  If SM for Compatible Mirroring for IBM FlashCopy Version2 is not activated, the area of SM accessed is incorrect.  Therefore, CHK3 occurs many times in the subsystem eventually resulting in WCHK1 and the DKA MPs are blocked.


Resolution

A) Actions to take in the case of failure:

The following steps should be performed only with the guidance of technical support.


step1: Power off, and then perform a volatile power-on
step2: Recover the blocked LDEV by formatting it
step3: Restore the data from the backup data
step4: Upgrade the micro-program to the modified one
step5: Create a ShadowImage/ShadowImage-Mainframe/Cross-system Copy/Compatible Mirroring for IBM FlashCopy pair/relationship again, and perform Volume Migration again.

B) In case the issue occurs but does not match the above contributing factors, collect the dump and contact the technical support organization.

INTERIM SOLUTION
For System with "below" DKCMAIN 50-07-51-00/00:

Don't upgrade the micro-program to DKCMAIN (V07+1) 50-07-51-00/00 or later.

For System with DKCMAIN 50-07-51-00/00 or above, perform either of the following operations:

a. Downgrade the micro-program to any version earlier than DKCMAIN V07+1 50-07-51-00/00.
(version down only under the guidance of technical support)
b. Install SM temporally to enable either of the following and then de-install SM after upgrading the micro-program to a fixed version.
1) To support Control Units greater than four.
2) In the Shared Memory Size Configuration panel, select the check box
"Flash Copy V2/COW snapshot"


FINAL SOLUTION
Please install the following modified microcode which fixes this issue:
Microcode: 50-07-69-00/00.  Please refer to the corresponding ECN for more details.


Previously Published As
102629
Internal Comments
Related Information
  • Other: HDS Alert: Storage-RAID:USP_049258, Storage-RAID:NSC55_049258

Internal Contributor/submitter
suresh.gummanur@sun.com

Internal Eng Business Unit Group
KE Authors

Internal Eng Responsible Engineer
suresh.gummanur@sun.com

Internal Services Knowledge Engineer
pete.stauffer@sun.com

Internal Kasp FAB Legacy ID
102629

Internal Sun Alert & FAB Admin Info
Critical Category:
Significant Change Date: 2006-09-25
Avoidance: Firmware
Responsible Manager: tejinder.singh@sun.com
Original Admin Info: null

Product_uuid
15644879-f179-11d8-ab63-080020a9ed93|Sun StorageTek 9990 System
73084edc-dc32-11d9-8a74-080020a9ed93|Sun StorageTek 9985 System

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