R.S Thanks for your information.
Also referred z/OS V1R7.0 DFSMS Using Data Sets as follows....
1.3.2.3 Maximum VSAM Data Size
A VSAM data set is limited to 4 GB across all volumes unless Extended
Addressability is specified in the SMS data class definition. System
requirements restrict the number of volumes that can be used for one data set
to 59.
Using extended addressability, the size limit for a VSAM data set is determined
by either:
Control interval size multiplied by 4 GB
The volume size multiplied by 59.
A control interval size of 4 KB yields a maximum data set size of 16 TB, while
a control interval size of 32 KB yields a maximum data set size of 128 TB. A
control interval size of 4 KB is preferred by many applications for performance
reasons. No increase in processing time is expected for extended format data
sets that grow beyond 4 GB. To use extended addressability, the data set must
be:
1.SMS-managed
2.Defined as extended format.
2.1.3 Extended Format VSAM Datasets
VSAM extended format data sets might have any combination of the following
optional attributes:
1. Data striping. This is called a striped data set.
2. Data compression. This is called a compressed format data set.
3. Extended addressability.
For example, a data set might be a striped compressed format data set with
extended addressability. Striping can reduce sequential access time.
Compression can reduce the disk space. Extended addressability increases the
maximum size of the data set. VSAM data sets must also be in extended-format to
be eligible for the following advanced functions:
* Partial space release (PARTREL)
* Candidate volume space
* System-managed buffering (SMB)
An extended-format data set for VSAM can be allocated for key-sequenced data
sets, entry-sequenced data sets, variable-length or fixed-length
relative-record data sets, and linear data sets. Certain types of key-sequenced
data set types are excluded. The following data sets cannot have an extended
format:
* Catalogs
* Other system data sets
* Temporary data sets
When a data set is allocated as an extended format data set, the data and index
are extended format. Any alternate indexes related to an extended format
cluster are also extended format. If a data set is allocated as an extended
format data set, 32 bytes (X'20') are added to each physical block.
Consequently, when the control interval size is calculated or explicitly
specified, this physical block overhead may increase the amount of space
actually needed for the data set. Figure 23 shows the percentage increase in
space as indicated. Other control intervals do not result in an increase in
needed space
- 3390 Direct Access Device
Control Interval Size Additional Space Required
512 2.1%
1536 4.5%
18432 12.5%
- 3380 Direct Access Device
Control Interval Size Additional Space Required
512 2.2%
1024 3.2%
2.1.3.1 Restrictions on Defining Extended-Format Data Sets
The following restrictions apply to defining extended-format data sets:
An extended-format data set does not permit the indexes to be imbedded with the
data (IMBED parameter) or the data to be split into key ranges (KEYRANGES
parameter).
Extended-format data sets must be SMS managed. These are the mechanisms for
requesting extended format for VSAM data sets:
Using a data class that has a DSNTYPE value of EXT and the subparameter R or P
to indicate required or preferred.
Coding DSNTYPE=EXTREQ (extended format is required) or DSNTYPE=EXTPREF
(extended format is preferred) on the DD statement.
Coding the LIKE= parameter on the DD statement to refer to an existing extended
format data set.
Note: An open for improved control interval (ICI) processing is not permitted
for extended format data sets.
More topics...
VSAM Data Striping:
http://publibfp.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/DGT2D440/2.1.3.2?SHELF=&DT=20050602124524&CASE=
Compressed Data....
http://publibfp.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/DGT2D440/2.1.3.3?SHELF=&DT=20050602124524&CASE=
Regards, Mani
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of
R.S.
Sent: Tuesday, March 24, 2009 9:21 PM
To: [email protected]
Subject: Re: How to identify the maximum size of VSAM LDS
Sivakumar, Manikandan pisze:
> Folks,
>
>
>
> I have a requirement to identify what is the maximum size allowed for
> VSAM LDS dataset. Is there any way to calculate or perform analysis on
> this.
LDS can grow up to 4GiB. Regular LDS, non-EA.
Extended Format LDS with Extended Addressability can grow up to 2^32
CI's *and* is limited to 59 volumes. For typical CI=4096B that gives
16TiB. Still 59 volumes limitation apply, for 3390-54 the real
limitation is approx. 3TB.
--
Radoslaw Skorupka
Lodz, Poland
--
BRE Bank SA
ul. Senatorska 18
00-950 Warszawa
www.brebank.pl
Sd Rejonowy dla m. st. Warszawy
XII Wydzia Gospodarczy Krajowego Rejestru Sdowego,
nr rejestru przedsibiorców KRS 0000025237
NIP: 526-021-50-88
Wedug stanu na dzie 01.01.2009 r. kapita zakadowy BRE Banku SA (w caoci
wpacony) wynosi 118.763.528 zotych. W zwizku z realizacj warunkowego
podwyszenia kapitau zakadowego, na podstawie uchway XXI WZ z dnia 16 marca
2008r., oraz uchway XVI NWZ z dnia 27 padziernika 2008r., moe ulec
podwyszeniu do kwoty 123.763.528 z. Akcje w podwyszonym kapitale zakadowym
BRE Banku SA bd w caoci opacone.
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