The system monitors the degree of saturation on pubsets in order to detect storage space bottlenecks on shared volumes in good time. Systems support can influence this monitoring by setting saturation levels, see section "Defining saturation threshold values for volume sets and SF pubsets". The saturation level is reached when less space is free on an SF pubset or volume set than is defined for the saturation level concerned.
Messages concerning the saturation level
If the saturation level reached changes, the messages EXC044i, DMS141C or DMS1400 are output to the console:
| Message in the case of SF pubsets when saturation level i is reached. |
| Message in the case of SF pubsets when the zip level is exceeded. |
| Message for volume sets of an SM pubset. The saturation level (0 through 6) is shown in the message, 6 standing for the zip level. |
Meassage EXC044E plays a special role, see "Handling the storage space requests" below.
The table below shows the operator actions depending on the saturation level:
Level | Effects on system | Operator measures |
0 | Normal system processing | None |
1-3 | Warning of impending saturation for a pubset or volume set | Inform systems support |
4 | Storage space requests by user jobs for a pubset or volume set are rejected with message | Inform systems support; |
5 | As for saturation level 4 with additional restrictions for system tasks | Inform systems support |
6 | As for saturation level 5 with an additional restriction for a session which is initiated with a type ZIP system start | Inform systems support After sufficient space has been made available on the volume, initiate a new session with a normal type system start |
Table 21: Saturation state of a pubset
Information on the saturation state of a pubset is also supplied by the SHOW-PUBSET-SPACE-ALLOCATION command.
Handling the storage space requests
Requests by user jobs are rejected if their fulfillment would lead to saturation level 4 being reached unless the system parameter L4MSG is assigned the value 1. In this case the following message requiring a response is output to the console for each user storage space request which would lead to saturation level 4 being reached, but not saturation level 5:
EXC044E SATURATION LEVEL 4 FOR PUBSET/VOLUMESET '(&00)' EXCEEDED. REQUEST FOR DISK SPACE ACCEPTED NEVERTHELESS? REPLY (Y=YES; N=NO)Operator granting of storage space requests (reply Y) should be restricted.
Requests for the TSOS user ID are accepted regardless of the reached saturation level as long as there is still a minimum storage space reserve left for the system after fulfillment. This emergency reserve is only used for a system start in ZIP mode.
Requests from system tasks can also be fulfilled with saturation level 4 or 5.
Requests for creating system dumps are rejected if their fulfillment would lead to saturation level 5.
With SM pubsets, an attempt is made to fulfill requests, which do not refer to a specific volume set in the pubset, on the volume set with the lowest saturation level (as long as it complies with the other volume set selection criteria). The request is rejected if its fulfillment would lead to a saturation level (as described above) being reached on all volume sets which are suitable for the allocation.
Saturation prevention measures
Occurrence of saturation level 4 or 5 indicates that the pubset or volume set concerned is overloaded. A pubset or volume set which continuously reaches this level is insufficiently configured.
Systems support can employ the following measures:
Redistribute separate user IDs to other pubsets
Enlarge the pubset or volume set by adding volumes
Migrate unused data with the software product HSMS
Issue regular requests to users to release storage space which is not required, and move files
Check storage space assignment with the SPCCNTRL utility or the SHOW-PUBSET-SPACE-ALLOCATION command
Economical use with the “storage space violation” function (ADD-USER PUBLIC-SPACE-EXCESS=*NO/*ALLOWED command)
Timely reorganization