Limiting the scope of a withdraw using the XTNTLST

XTNTLST acts in conjunction with the other withdraw techniques such as target only, source and target, and DDSW, to restrict which relationships are affected by the withdraw command processing. The XTNTLST becomes an additional filter to determine which relationships and tracks are processed.

If DDSW(YES) is not specified, this is considered a partial withdraw. If an existing relationship intersects the specified extent ranges, only those tracks within the specified ranges will be withdrawn, and an extent split will occur to create one or more new relationships for the remaining tracks not being withdrawn. The request could fail if the additional relationship(s) cause you to go beyond the maximum number of relationships allowed.

If DDSW(YES) is specified, handling of the extent specification is somewhat different. If an existing relationship intersects a specified extent range, that entire relationship will be withdrawn, even if it contains tracks which are not within the specified range.

The following provides an example of how you can limit the scope of a DDSW(YES) withdraw using the XTNTLST parameter. The basis for this example is Figure 1 . The processing that occurs is based on the issuance of the following command and supporting assumptions.

Example assumptions:

The extent range c1h1 through c2h2 includes the last 5 tracks from the source extent for the COPY relationship between Volume A and Volume B.
The extent range c1h1 through c2h2 includes all tracks from the source extent for the COPY relationship between Volume A and Volume D.
The extent range c1h1 through c2h2 includes all tracks from the target extent for the relationship between Volume C and Volume A.
The extent range c1h1 through c2h2 includes the first 37 tracks from the target extent for the relationship between Volume E and Volume A.

The following events occur when the command FCWITHDR SDEVN(ssss) DDSW(YES) XTNTLST (c1h1 c2h2 c3h3 c4h4) is processed against Volume A:

All target tracks on volume A in the relationship with volume C are removed from that relationship. All target tracks on volume A in the relationship with volume E are removed from that relationship, even though some of those tracks lie outside of the specified c1h1 through c2h2 extent range.
For the FlashCopy® relationship that is established using the NOCOPY mode between volume A and volume B, the following occurs:
1. All FlashCopy source tracks in this relationship are changed to COPY (background copy) source tracks, even though some of those tracks lie outside of the specified c1h1 through c2h2 extent range.
2. The tracks are physically copied to their respective target tracks.
3. When the background copy is complete, all tracks are removed from that FlashCopy relationship.
For the FlashCopy relationship that is established using the COPY mode between volume A and volume D, all tracks lie within the specified c1h1 through c2h2 extent range. The relationship does not need to be converted from NOCOPY to COPY, and the existing background copy task is allowed to complete and tracks removed from that relationship at that time (normal behavior).
For the FlashCopy relationship that is established using the NOCOPY mode between volume A and volume E, all tracks lie outside of the specified c1h1 through c2h2 extent range. The relationship is not affected by processing for this command, and continues to exist in NOCOPY mode.

For additional information about the XTNTLST parameter, refer to page XTNTLST.