Message data set allocation

Fast replication message data sets must be SMS-managed. DFSMShsm allocates the physical sequential data sets with these attributes:

Record format: FBA
LRECL: 121
Block size: 1210

Message data set names have the following format:

For FRBACKUP requests: msgdsprefix.FB.Cccccccc.ippppppp.Dyyddd.Thhmmss.z
For FRRECOV requests: msgdsprefix.FR.Cccccccc.ippppppp.Dyyddd.Thhmmss.z

where:

msgdsprefix

is the value of the HLQ parameter of the SETSYS FASTREPLICATION(MESSAGEDATASET) command, if specified. If the HLQ parameter is not specified, the default prefix of 'HSMMSG' is used.

ccccccc

is up to 7 characters to identify the copy pool that was processed. For a non-DB2 copy pool, this will be the first 7 characters of the copy pool name. For a DB2 copy pool, this will be the first 7 characters of the location qualifier in the DB2 copy pool name.

i

is a 1-character identifier, indicating whether the message data set contains messages regarding:

D: DB2 data
L: DB2 log
X: non-DB2 copy pool data

ppppppp

is up to seven characters to identify the copy pool that was processed. For a non-DB2 copy pool, this is the next seven characters of the copy pool name (the characters following ccccccc). For a DB2 copy pool, this is the next seven characters of the location qualifier in the DB2 copy pool name.

yyddd

is the year and day when the FRBACKUP, FRRECOV, or copy pool auto dump operation started.

hhmmss

is the time in hours, minutes, and seconds when the FRBACKUP, FRRECOV, or copy pool auto dump operation started.

z

indicates the status of the FRBACKUP, FRRECOV, or copy pool auto dump operation, and is set to one of the following:

S: Success. The operation completed successfully.
F: Fail. One or more errors occurred while processing the operation.
I: In progress. DFSMShsm allocates the data set with this final qualifier, and renames the data set with one of the other qualifiers once the operation completes

When DFSMShsm attempts to allocate a message data set and a data set with the selected name already exists, DFSMShsm increments the time stamp in the data set name by one second and attempts to allocate with this new name. DFSMShsm renames the data set up to a maximum of 10 times, and if a unique message data set name is not found, an ARC1873I message is issued and messages are not captured for this request.

You can specify the date and time used in the message data set name with the MESSAGEDATASET parameter of the FRBACKUP command and the FRRECOV COPYPOOL command. Refer to FRBACKUP command: Requesting a fast replication backup or dump version and FRRECOV command: Requesting a fast replication recovery.