>From the DFSMS Using Data Sets manual: *PDSE Unused Space*
PDS gas is the unreclaimed space in a PDS that was vacated when members were deleted or rewritten. Users often overallocate their PDSs to allow for the inevitable amount of PDS gas that would develop over time. With PDSEs, you do not need to add additional space to the allocation to allow for growth of the data set due to gas. Studies show that a typical installation has 18% to 30% of its PDS space in the form of gas. This space is unusable to the data set until it has been compressed. A PDSE dynamically reuses all the allocated space according to a first-fit algorithm. You do not need to make any allowance for gas when you allocate space for a PDSE. Space is only reclaimed for an OPEN for output when it is the only open for output on that system. PDSE space cannot be reclaimed immediately after a member is deleted or dated. If a deleted or updated member still has an existing connection from another task (or the input DCB from an ISPF edit session), the member space is not reclaimed until the connection is released and the data set is opened for output and that OPEN for OUTPUT is the only one on that system. ABEND D37 can occur on a PDSE indicating it is FULL, but another member can still be saved in the data set. Recovery processing from an ABEND D37 in ISPF closes and reopens the data set. This new open of the data set allows PDSE code to reclaim space so a member can now be saved. - Don Imbriale On Thu, Jan 19, 2012 at 7:26 AM, Juergen Keller < juergen.kel...@deutsche-boerse.com> wrote: > hello, > > I have a very strange "problem". Maybe there is someone having an idea how > to solve it. So what happens: > > We have a pdse-load-library (with only primary allocation - no secondary!) > for testing software. Now when testing a new versions we first delete all > members with a batch-job and copy the new version to this dataset. This > worked fine in the past but now ... > > ... we added this dataset to LINKLIST to get rid of the steplib. When I > now delete all members and copy the new version to that dataset I will > receive D37. I can see that after deleting all members the dataset is still > filled with 80%. Someone told me that I have to do a LLA REFRESh afterwards > but that did not help. When you browse that dataset ISPF says that there > are no members in, but its still 80% used. Then I do an ISPF-COPY for one > member and then its only filled with 1%. When doing the same with a batch > job it does not help. > > I'm quite sure that it has to do with the LINKLIST and the PDSE-format. I > tested it with z/OS 1.10 and 1.12 .. no difference. Has anyone had the same > problem before and has a solution for me? Any comments are welcome. > > regards Juergen > > > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN
