Question & Answer
Question
What should I do if I receive an ABEND S878-10 when using BUFNO in my SORTINxx DD statements?
Cause
In DFSORT release V2R2 we made a change to prefer the BSAM access method over EXCP. This change was made to leverage zHPF. This caused some changes to how above/below the line storage is used. EXCP does not honor the BUFNO parameter, whereas BSAM does honor the BUFNO parameter. Typically, a user previously used EXCP, and that is why BUFNO is specified. However, users may be unaware of the preference change from EXCP to BSAM, which can cause confusion.
Answer
When the BUFNO parameter is specified within the SORTIN DD JCL statement, upon allocation, DFSORT will use the following calculation for determining the amount of below the line storage: (number of data sets) x (block size) x (BUFNO) = storage being used below the line. Therefore, when you receive an S878-10, that means DFSORT is attempting to use more below the (16-megabyte) line storage than is available.
For example, if there are 10 SORTIN data sets with a BLKSIZE of 32580 and BUFNO of 200 specified within the SORTIN DDs. Therefore, the amount of below the line storage needed would be 10 (# of data sets) X 32580 (BLKSIZE) X 200 (BUFNO) = 65,160,000 bytes ~ 65 MB. Since this much below the line storage is not available, the abend 878 occurs. To avoid this abend 878, it is recommended to remove the BUFNO or parameter from your JCL with respect to the SORTIN DDs. DFSORT can manage its own buffers. If there is a need for the BUFNO parameter, it still can be used, but not to the extent where it exhausts all of the available below the line storage.
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Document Information
Modified date:
28 February 2020
UID
ibm11088860