>>-+-----------------------------------------------------+-----><
   |                .-,1-.     .-PASSDelay(999)--------. |   
   '-MAXmove--(--n--+----+--)--+-----------------------+-'   
                    '-,p-'     '-PASSDelay--(--nnnn--)-'     

n

Specifies a 1- to- 6 digit number that specifies that DFSMSdss is to attempt to assemble up to n free tracks in a contiguous area. If n is greater than the total number of free tracks on the volume, for example MAXMOVE(999999), a message is issued and the DEFRAG operation adjusts n to the number of free tracks.

p

Specifies a 1- to- 2 digit number that specifies that DFSMSdss is to make up to p passes in attempting to assemble the tracks. If p is not specified, for example MAXMOVE(99), only one pass is made, that is, MAXMOVE(99,1).

PASSDelay

specifies the time delay between the passes (p) specified in MAXMOVE (n,p). PASSDELAY is only meaningful if (p) is greater than one.

nnnn

Specifies a 1- to- 4 digit number from 0 to 9999 that specifies the time delay in milliseconds (1/1000 of a second). When MAXMOVE (n,p) is specified and PASSDELAY is not specified, a default PASSDELAY value of 999 (almost a second) is used to allow access to the volume between MAXMOVE passes.

DEFRAG processing attempts to move a fraction of the total free tracks during each pass. DEFRAG processing calculates an integer limit that is the larger of n divided by p or the value of 15. The limit is compared to the cumulative number of tracks moved after each extent is moved. If the limit is reached or exceeded, the current pass ends, and a new pass starts. Between each pass, the DEFRAG function releases and re-obtains volume serialization. This action reduces the overall time that a DEFRAG operation makes a volume unavailable to other applications.

The DEFRAG operation may end before completing p passes. If the DEFRAG operation cannot assemble n contiguous free tracks without moving more than n tracks, DFSMSdss issues a message and ends the DEFRAG operation. If n contiguous free tracks exist, the DEFRAG operation still attempts to reduce the fragmentation of the volume if it can do so without relocating more than n tracks.

The operation or the current pass also ends when DEFRAG processing criteria (for example, FRAGI) are satisfied. If you specified more than one pass, only the current pass ends. DFSMSdss issues message ADR233W for the current pass when the FRAGI criteria has been met. The DEFRAG function continues to run and attempts to complete the specified number of passes. DFSMSdss issues message ADR233W for each pass that meets the FRAGI criteria. The function continues because activity on the volume between the DEFRAG passes may change the fragmentation index and the subsequent DEFRAG passes may further reduce the fragmentation of the volume.

In order to re-obtain volume serialization between DEFRAG passes, DFSMSdss uses a default value of WAIT(3,30). This means that DFSMSdss is to retry the volume serialization 30 times at 3 second intervals for a total wait time of 90 seconds. The DEFRAG operation issues a message and ends if DFSMSdss cannot obtain volume serialization; any remaining passes do not run. The WAIT option explains how to change the wait/retry values for the volume serialization if the default is not satisfactory.

If MAXMOVE is not specified, DFSMSdss tries to assemble a contiguous free area of a size equal to the total number of free tracks on the volume in a single pass. The DEFRAG function uses two methods to assemble free tracks on the volume. The first method attempts to assemble the largest contiguous amount of free space with a minimum amount of data movement. The second method attempts to assemble multiple groups of large areas of contiguous free space and generally moves more data around than the first method. When MAXMOVE is specified, only the first method is used during each pass.