DFSMShsm determines if a data set has
expired based on the expiration
date found in the catalog entry of the data set. OAM determines if
an object has expired based on the expiration date in its object directory
entry. If an expiration date is not found, DFSMShsm and OAM use the
management class expiration attributes. These attributes are used
as follows:
- If both expiration attributes are NOLIMIT, the data set or
object
never expires.
- If one of the expiration attributes is NOLIMIT,
then the other
attribute must be satisfied.
- If neither expiration attribute
is NOLIMIT, both of the expiration
attributes must be satisfied.
Tip: If you want to change
the expiration date in a catalog entry, you can either use the access
method services ALTER command or you can specify either the RETPD
or EXPDT parameter in the JCL for an old managed non-VSAM data set,
as long as the new expiration date is valid based on the retention
limit specified. See
z/OS DFSMS OAM Planning, Installation, and Storage Administration Guide for Object Support for
information on changing the expiration date of an object.
Data sets or objects having
the INTERIM management class defined
in Defining management class expiration attributes become eligible for expiration
when both
of the following criteria are met: at least seven days since allocation
and not referenced in the last two days.
Table 1 shows several combinations of retention
attributes used for space management processing. Use the highlighted
values for each instance.
Table 1. Comparing Retention
Period AttributesAttribute |
Case 1 |
Case 2 |
Case 3 |
Case 4 |
Case 5 |
Retention Limit |
0 |
50 |
100 |
NOLIMIT |
100 |
Expire after Days Non-usage |
50 |
50 |
50 |
50 |
50 |
Expire after Date/Days |
100 |
100 |
100 |
100 |
100 |
RETPD/EXPDT |
60 |
60 |
60 |
60 |
|
In the
first case, the retention limit is zero, so DFSMShsm
and OAM honor the values of 50 and 100 which are the values specified
for Expire after Days Non-usage and Expire after Date/Days and ignore
any user-specified or data class values. In Case 2, the management
class expiration values are ignored because RETPD and EXPDT values
have been specified or derived and the retention limit is nonzero.
However, because the retention limit is less than the user-specified
or data class values, 50 is saved and used to calculate the expiration
date.
In Case 3, the user-specified or data class values fall
within
the retention limit. So, DFSMShsm uses the values of 60 and 60. OAM
uses a RETPD value of 60, because OAM does not consider EXPDT.
In
Case 4, the RETPD and EXPDT are used because the retention period
value is NOLIMIT.
In Case 5, because no user-specified or data
class derived values
are available, DFSMShsm and OAM use the values specified in the management
class expiration attributes which are shown on the Management Class
Define panel.
After you specify the expiration attributes, issue
the DOWN command
to see the next page of the Management Class Define panel, on which
you can specify the migration attributes.