DB2 FOR LUW / DB2FORLUW / A50 - DB2

This DB2 APAR has been created to reference an RSCT APAR deemed 
critical to DB2 pureScale operations. 
 
 
RSCT APAR IV68484 
 
http://www-01.ibm.com/support/docview.wss?uid=isg1IV68484 
 
There were 2 fundamental issues with TB_BREAK , RSCT APAR 
IV68484 
(http://www-01.ibm.com/support/docview.wss?uid=isg1IV68484) is 
supposed to resolve on Linux : 
 
1. Return RC=0 when both parent map + all slave paths does not 
hold any reservations ..  Without the fix, any PR OUT RELEASE 
sys-call will return -1 if there are no existing reserves from 
that path, which is then incorrectly interpreted by 
IBM.TieBreaker class as a failure and exit with RC=104. 
 
2. Re-discover the path map right before any PR OUT service 
action is issued. ...   Without the fix, the path map (list of 
slave-paths under the parent DM device) is only discovered right 
at the start of tb_break run-time.  This fix is supposed to 
handle cases where there is brief a path/controller failure 
which cause Linux kernel to remove-and-reinstantiate the path(s) 
potentially causing DM device path map changes (i.e /dev/sdd 
under dm-5 can be become /dev/sdz for example) during the 
run-time of tb_break .. 
 
 
The net affect from a pureScale customer scenario is that during 
DB2 instance creation, the validation of the RSCT tie breaker 
disk could fail resulting in no tie breaker. A second issue, and 
of much higher concern, during runtime of DB2 pureScale if a 
cluster failure occurs , the reservation of the tie breaker disk 
could incorrectly fail potentially resulting in a complete 
cluster outage. From a DB2 perspective, this is a HIPER APAR.

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* USERS AFFECTED:                                              * 
* See Error Description                                        * 
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* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
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* RECOMMENDATION:                                              * 
* See Local Fix                                                * 
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Apply RSCT APAR fix.

not known / see Local fix

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

18.06.2015
20.01.2016
20.01.2016