At regular intervals, HSMS checks whether a saturation level has been reached on a pubset. Depending on this check, HSMS supplies the $SYSHSMS.SYS.HSM.MIGRATE.<pubset-id> job variable, on a pubset-specific basis, with values for all pubsets entered in the control file.
HSMS also carries out similar checks for all volume sets belonging to an SM pubset under HSMS control. HSMS then delivers the job variables $SYSHSMS.SYS.HSM.MIGRATE.<vol-id> which are located on the corresponding SM pubset.
By interrogating this job variable in enter jobs or programs, the HSMS administrator can provide for an automatic response to any saturation states and thus migrate enough files to eliminate the saturation levels on the SF pubsets or the volume sets of the SM pubset. The number of necessary pages depends on the saturation levels set and is likewise passed in the job variable. The quantity to be migrated can then be specified in MIGRATE-FILES, using the RELEASE-PAGES operand.
Unless they already exist, the job variables are automatically generated by HSMS at startup. The job variables are stored as non-shareable under the SYSHSMS ID (on the home pubset for an SM pubset and on the SM pubset for the included volume sets). The attributes of the job variables must not be modified.
If HSMS is not loaded or loaded only in definition/information mode, the job variables contain X’FF...’ for the first 40 bytes. In the other modes, the job variables are updated on startup for SF pubsets or on import of each such SM pubset and every 10 minutes thereafter. The saturation level reached on a given pubset is entered in the job variable for the pubset.
The contents of the job variable have the following meaning:
Position | Length | Meaning |
1 | 1 | Pubset status: |
2 | 1 | Fill character |
3 | 1 | Pubset saturation level |
4 | 2 | Fill character |
6 | 10 | Number of occupied PAM pages |
16 | 5 | Fill character |
21 | 10 | Total capacity of the pubset in PAM pages |
31 | 5 | Fill character |
36 | 10 | Number of PAM pages exceeding the saturation level indicated, if one has been reached |
46 | 3 | Fill character |
49 | 12 | Date at which the job variable was set to the current value |
61 | 5 | Fill character |
66 | 8 | Time at which the job variable was set to the current value |
74 | 2 | Fill character |
76 | 181 | Fill character |
Note
For SM pubsets, this mechanism is available at volume set level only and not for the entire SM pubset.
This information can be used to control the specific migration operation.
Examples of an enter job and a program can be found at the end of this section, starting on "Migration examples".