Subject: Re: VSAM limits
RJacobson@decare.com
Date: Fri Nov 06 2009 - 12:50:16 EST
26K CI size on the data component give you 798,720 bytes/cyl, while 4K CI
size will only give you 737,280 bytes/cyl, about 8% less.
If the index component can only have 64,511 CI's, the vast majority of them
will be used for the sequence set, but some will be needed for the higher
level index. The exact number of index CI's taken up for the higher levels
of the index varies with the CI size of the index component. If your file
used the maximum index CI size (8K), and if the poster you were responding
to used a smaller index CI size, then you would have had more of the 64,511
index CI's mapped to data CA's then he did, which could account for why
your file is 30% larger than the maximum size he quoted.
Bob Jacobson
(651) 994-5329
industrynews@winw
holesale.com
Sent by: To
owner-vse-l@Lehig "VSE Discussion List"
h.EDU <vse-l@Lehigh.EDU>
cc
11/06/2009 10:40 Subject
Re: VSAM limits
Please respond to
vse-l@Lehigh.EDU
owner-vse-l@Lehigh.EDU wrote on 11/05/2009 04:27:12 PM:
> Thus, a Shareoption(4) file may not have more than 64511 (64K-1024)
> control areas, and the maximum file size would be 64511 times your
> control area size.
Yep, 64511 is the number I was talking about earlier in reference
to the maximum number of CI's in a KSDS index component.
> If you use the maximum control area size for your file of one cylinder,
> define the file as XXL, and reside on 3380, with a CISIZE of 4K, this
> would set a maximum file size of 36.9GB.
I was unaware of this associated limit on the data component.
Thanks. But, I have a 47.8GB XXL dataset at the moment. Is this because I
am using a 26K CI size for half-track blocking?
Sincerely,
Dave Clark
WinWholesale Group Services
3110 Kettering Boulevard
Dayton, Ohio 45439 USA
(937) 294-5331
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