Checkpoint and Spool Data Sets

Spool
requires one checkpoint data set and one or more spool data sets.
casp14
Spool
requires one checkpoint data set and one or more spool data sets.
Installation
The checkpoint data set and spool data sets must be permanently allocated as part of the installation process.
Optionally, a secondary checkpoint data set is defined, which is a copy of the primary checkpoint data set. The secondary data set is used for manual recovery if the primary checkpoint data set becomes unusable.
Checkpoint Data Set Name
The name of the data set used for checkpoint is specified in the CHKPTDS initialization statement.
Location
The checkpoint data set can reside on any type of direct access device. The location is specified in the CHKPTDS initialization statement.
We recommend that you allocate the checkpoint data set on a low impact volume that is separate from the spool data sets.
Space Allocation
Allocate the checkpoint data set in cylinders, and in one extent.
Spool
uses only the first extent of the data set for checkpointing and ignores any additional extents. For information about calculating the checkpoint data set size, see the Checkpoint Data Set Size Calculation section in Storage Estimates.
SPOOL Data Sets
The name of a data set used for spooling is specified in the SPOOLDS initialization statement. The default spool data set name is SYS1.ESFSPOOL.
  • Multiple spool data sets on one volume are supported.
  • 3390-9 DASD and 3390-A DASD are supported.
  • DSNTYPE=LARGE spool data set supported to allow spool data sets with up to 1,048,575 tracks (69,905 cylinders).
  • You can add new spool data sets to a running
    Spool
    system. No format start is required; simply specify the new spool data sets in ESFPARM and perform a REINIT.
  • Added spool data sets are automatically formatted during REINIT. Multiple spool data sets are formatted in parallel.
  • EATTR=OPT and DSNTYPE=LARGE are required for allocation of any size spool data set on an EAV device.
Location
Spool data sets can reside on any combination of direct access devices. The spool data sets are specified by SPOOLDS initialization statements.
It is recommended that you allocate the spool data sets on low impact volumes and separate from the checkpoint data sets.
Space Allocation
The spool data sets must be allocated in cylinders, and in one extent.
Spool
uses only the first extent of these data sets for spool space and any additional extents are ignored. The block size must not be too small, because a maximum of eight blocks per track is used. The block size is specified in the BUFSIZE statement.