ABCs of z/OS System Programming Volume 3 - IBM Redbooks

7.1 VSAM share options
Share options are an attribute of the data set
SHAREOPTIONS(crossregion,crosssystem)
SHAREOPTIONS(1,x)
Figure 7-1 VSAM share options
Share options as a data set attribute
The share options of a VSAM data set are specified as a parameter for an IDCAMS DEFINE
CLUSTER that creates a new data set. They show how a component or cluster can be shared
among users.
SHAREOPTIONS (crossregion,crosssystem)
The cross-region share options specify the amount of sharing allowed among regions within
the same system or multiple systems. Cross-system share options specify how the data set is
shared among systems. Use global resource serialization (GRS) or a similar product to
perform the serialization.
SHAREOPTIONS (1,x)
The data set can be shared by any number of users for read access (open for input), or it can
be accessed by only one user for read/write access (open for output). If the data set is open
for output by one user, a read or read/write request by another user will fail. With this option,
VSAM ensures complete data integrity for the data set. When the data set is already open for
RLS processing, any request to open the data set for non-RLS access will fail.
SHAREOPTIONS (2,x)
The data set can be shared by one user for read/write access, and by any number of users for
read access. If the data set is open for output by one user, another open for output request
will fail, but a request for read access will succeed. With this option, VSAM ensures write
378 ABCs of z/OS System Programming Volume 3
One user can have the data set open for read/write
access or any number of users for read only
SHAREOPTIONS(2,x)
One user can have the data set open for read/write
access and any number of users for read only
SHAREOPTIONS(3,x)
Any number of users can have the data set open for
both read and write access