IMS/ESA Shared Queues: A Planning Guide

IXL013I IXLCONN REQUEST FOR STRUCTURE IMA0MSGQ FAILED

CQS0014E STRUCTURE IMA0MSGQ INIT FAILURE; FUNC=CONN

JOBNAME:IMA1CQS ASID:024B CONNECTOR NAME:CMA1CQS

IXLCONN RETURN CODE:0000000C, REASON CODE:02010C08

Figure 27. CQS Messages Issued on Startup when the Structures are too Small

IXLCONN return and reason codes are detailed in

OS/390 MVS Programming:

Sysplex Services Guide

, GC28-1771. After the IXL messages, CQS abended with

the following message:

BPE0006I U0014 - 00000200 INVALID STRUCTURE SIZE

The minimum we used for the logger structure was 512 KB; using a value less

than this produced the following message:

IXG231I IXGCONN REQUEST=CONNECT TO LOG STREAM SYSPLEX.IMS.MSGQ ...

RETURN CODE:00000008 REASON CODE:00000853

IXGCONN return and reason codes are explained in

OS/390 MVS Programming:

Assembler Services Reference

, GC28-1910. After the IXG message, CQS

abended with the following BPE message:

BPE0006I U0014 - 000000A0

7.3 Minimum SRDS Size

CQS uses two structure recovery data sets (SRDS) for each structure pair

(SRDS1 and SRDS2 for each message structure). They are used to save

coupling facility structure contents when a structure checkpoint is taken.

Structure checkpoint requests alternate between the two structure recovery data

sets.

SRDSs are dynamically allocated when a structure checkpoint begins as well as

during any structure recovery activity. They will be deallocated when the

activities end; CQS therefore holds the SRDS only while a structure checkpoint

or a structure recovery is in process.

For SRDS sizing, we tried to take a structure checkpoint with an SRDS that was

not large enough to contain the whole coupling facility structure. Figure 28

shows the IDCAMS statements we used to make the full-function SRDS very

small (one track).

DEFINE CLUSTER -

(NAME(IMA0.CQS.MSGQ.SRDS1) -

TRK(1) -

NONINDEXED -

SHAREOPTIONS(2,3) -

RECSZ(32761,32761) -

REUSE -

CISZ(32768) -

VOLUMES(S00006))

Figure 28 (Part 1 of 2). Defining SRDS with IDCAMS

Chapter 7. Setup and Startup Tests 61

DEFINE CLUSTER -

(NAME(IMA0.CQS.MSGQ.SRDS2) -

TRK(1) -

NONINDEXED -

SHAREOPTIONS(2,3) -

RECSZ(32761,32761) -

REUSE -

CISZ(32768) -

VOLUMES(S00006))

Figure 28 (Part 2 of 2). Defining SRDS with IDCAMS

Then we tried to initiate a checkpoint with the following command:

/CQCHKPT SHAREDQ STRUCTURE ima0messageq

The following message was received:

DFS1974I CQCHKPT SHAREDQ REQUEST REJECTED FOR STRUCTURE=IMA0MSGQ, REASON CODE = 5

This message means there was a CQS internal error. The messages from the

CQS address space are shown in Figure 29.

CQS0220I CQS CMA2CQS STARTED STRUCTURE CHECKPOINT FOR STRUCTURE IMA0MSGQ

CQS0200I STRUCTURE IMA0MSGQ QUIESCED FOR STRUCTURE CHECKPOINT CMA2CQS

IEC070I 203-204,IMA2CQS,IMA2CQS,SRDSD101,1295,S00006,

IEC070I IMA0.CQS.MSGQ.SRDS1,IMA0.CQS.MSGQ.SRDS1.DATA,CAT.USER03.A00

CQS0201I STRUCTURE IMA0MSGQ RESUMED AFTER STRUCTURE CHECKPOINT CMA2CQS

CQS0054E WRITE FAILED FOR SRDSDSN1, RC=00000008/2908001C CMA2CQS

CQS0054E DSN=IMA0.CQS.MSGQ.SRDS1 CMA2CQS

CQS0222E CQS CMA2CQS FAILED STRUCTURE CHECKPOINT FOR STRUCTURE IMA0MSGQ

Figure 29. Messages Issued by CQS When a Structure is Not Large Enough

Message IEC070I is issued when there is no more space in the structure.

CQS and IMS both continued processing, but the structure checkpoint was not

taken, thereby jeopardizing any later structure recovery if the need should arise.

Thus, the SRDS must be large enough to contain the primary structure and the

overflow structure (if it has been defined) to avoid the exposure caused by failed

structure checkpoints.

If the SRDS is redefined (delete/define) while CQS is active and no structure

checkpoint is taken, then the next time that CQS restarts, the following message

is received:

CQS0009W STRUCTURE IMA0MSGQ REQUIRES STRUCTURE CHECKPOINT FOR RECOVERY

and a structure checkpoint must be taken so that structure recovery can be

performed if the need arises.

62 IMS/ESA Shared Queues Planning Guide