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morpheus007
New User
Joined: 27 Dec 2005
Posts: 58
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I am trying to find out the amount of space used so far and the amount of space left in case of a vsam file.
Please let me know how to determine that. |
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Bill Dennis
Active Member
Joined: 17 Aug 2007
Posts: 562
Location: Iowa, USA
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| After the file is CLOSED, run a LISTCAT and check the difference in HARBA and HURBA amounts. |
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dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006
Posts: 19244
Location: Inside the Matrix
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Hello,
How might this be a jcl question?
You might do a bit of research on LISTDSI. . . The forum search would be a good place to start. |
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Robert Sample
Global Moderator
Joined: 06 Jun 2008
Posts: 8696
Location: Dubuque, Iowa, USA
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The High Allocated RBA (HARBA) in a LISTCAT output gives the number of bytes allocated (technically, the offset to the highest allocated byte). The High Used RBA (HURBA) in a LISTCAT output gives the offset of the highest used byte; the difference is the amount of free space in the file. Is the free space usable? Good question with no easy answer. Maybe -- depending on (average) record length, CI size, CI free space percentage and CA free space percentage. Worst case is that none of the free space is usable -- for example, the record length is 1050 bytes (fixed), the CI size is 4096 and the CI free space percent is 20 percent -- which gives just over 800 bytes per CI free but it is not enough to write a record so none of the free space will be used.
The "amount of space left" in a VSAM file depends -- potentially a VSAM file can be 4 GB if not extended format, much larger if extended format. But the actual amount of space left (i.e., potentially allocatable space) can be affected by the number of extents already used, the number of disk packs the file is on, how many disk packs are candidate volumes, and so forth.
There is an excellent redbook on VSAM called VSAM Demystified that is well worth the time to go through. |
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morpheus007
New User
Joined: 27 Dec 2005
Posts: 58
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| thanks a lot for the help on this topic. Also i apologize for posting the question in the section. |
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morpheus007
New User
Joined: 27 Dec 2005
Posts: 58
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| Wrong section |
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Robert Sample
Global Moderator
Joined: 06 Jun 2008
Posts: 8696
Location: Dubuque, Iowa, USA
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| Glad to hear it helped -- and I've moved the topic. |
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