VSAM Performance Enhancement › Advanced Topics › VPE Implementation Considerations › SHAREOPTION=4 Files

SHAREOPTION=4 Files

This VSAM processing option allows multiple CPUs or address spaces to have concurrent write access to a data set. Unless your environment requires this type of access, it is generally inadvisable. Specifying SHAREOPTION=4 requires VSAM to perform a physical I/O to refresh the buffer contents each time the record is read or written, so buffering these files is useless and VSAM does not permit LSR for such data sets. Review your cluster definitions to ensure that SHAREOPTION=4 is still appropriate.