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DS8700/DS8800 EasyTier extent migration may cause repeated warmstarts and potential access loss when both RAID-5 and RAID-6 arrays are configured in the system.

Flash (Alert)


Abstract

DS8700/DS8800 customers running EasyTier extent migration may experience repeated warmstarts with Fixed Block (FB) extents AND both RAID-5 and RAID-6 arrays are configured. Both EasyTier Auto Mode and EasyTier Manual mode (volume migration/rebalance, Rank Depopulation) are exposed. Customers with volume 0x0000 defined will experience more severe warmstarts and impacts (a potential loss of access), than those without this volume defined.

Content

Customers not on DS8700/DS8800 are not exposed.
This is applicable only to FB extents and not to Key Count Data (CKD) extents, and customers not having RAID-5 and RAID-6 are not exposed.
Customers at, or above the code bundles recommended below are not exposed to this issue.

Mitigation
Upgrade to the code levels indicated in this notification OR follow the instructions below to disable EasyTier Auto Mode until the code levels are installed.

Check if ET is running disable ET Auto Mode and stop all ET manual mode operations.
Note: Identify Storage Image ID (note the last digit of ID is always "1") of the DS8000 by DSCLI command "lssi". Below is an example output:

dscli> lssi
Date/Time: October 14, 2013 11:05:53 AM CST IBM DSCLI Version: 7.6.10.511 DS: -
Name ID Storage Unit Model WWNN State ESSNet
============================================================================
- IBM.2107-75xxxx1 IBM.2107-75xxxx0 951 5005yyyyyyyyyyyy Online Enabled

Run the following DSCLI command to show if ET Auto Mode is running:
dscli> showsi IBM.2107-75xxxx1

If the output shows etautomode is set to "none" or etmonitor is set to "none", ET Auto Mode is not running, otherwise, ET Auto Mode is running

Run the following DSCLI command to disable ET Auto Mode. The disablement takes effect within 5 minutes:
dscli> chsi -etautomode none IBM.2107-75xxxx1

Run the following DSCLI command to pause all ongoing volume migration/re-balance, takes effect immediately:
dscli> managefbvol -action migpause volumeIndex

Run the following DSCLI commands to abort all ongoing rank depopulation, takes effect immediately:
dscli> chrank -reserve rankNum
dscli> chrank -release rankNum

Corrected levels of code

The fix is available in the following bundles.
86.31.49.0 or higher - DS8800 ( R6.3)
76.31.32.0 or higher - DS8700 ( R6.3)

86.20.129.0 or higher - DS8800 (R6.2)
76.20.106.0 or higher - DS8700 (R6.2)

Cross reference information
Segment Product Component Platform Version Edition
Disk Storage Systems System Storage DS8700 N/A 6.2 N/A

Document information

More support for: System Storage DS8800

Version: Version Independent

Operating system(s): Open Systems

Software edition: N/A

Reference #: S1004487

Modified date: 30 September 2014


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