The sizing requirements for the definition of VSAM files as system journals in IDMS is documented in several places:
DISK JOURNAL Statements (scroll to "Block size of Disk Journal File" ), Journal Buffers and Journal Sizes (scroll to "Sizing Journal Buffers")JOURNAL BUFFER Statements
The above documentation is not specific. The following is required:In the VSAM file definition, the RECSZ must be 8 bytes less than the CISZ.
In IDMS, the definition of the journal buffer page size must be the same as the CISZ.
During the FORMAT, IDMS will recognize that this is a VSAM file and subtract 8 from the journal buffer page size.
Furthermore, if the CISZ is less than 8192, it must be a multiple of 512.
For example, use the following.
In the VSAM file:
RECSZ(2040 2040)
CISZ(2048)
In the IDMS journal buffer:
ALTER
JOURNAL BUFFER GLBLDMCL.JNL_BUFFER
PAGE SIZE 2048 CHARACTERS
BUFFER PAGES 5
;
The FORMAT output should look like this:
CONNECT TO SYSTEM;
Status = 0 SQLSTATE = 00000
FORMAT JOURNAL ALL;
Journal file J1JRNL 500 blocks written - size 2,040.
Journal file J2JRNL 500 blocks written - size 2,040.
Journal file J3JRNL 500 blocks written - size 2,040.
Journal file J4JRNL 500 blocks written - size 2,040.
Status = 0 SQLSTATE = 00000