Is there a performance penalty if one defines the DASD with the shared
attribute when running in a monoplex.
Not much. When a RESERVE macro is issued, a RESERVE CCW will be issued,
either immeditely (SYNCHRES=YES) or prefixed on the next I/O to the disk
(SYNCHRES=NO). When a DEQ macro is issued corresponding to that RESERVE
(or really when the reserve count goes to zero), a stand-alone RELEASE
CCW is issued. The overhead is minimal.
The only place I ever heard of it being a significant factor is on JES2
checkpoint, where RESERVE is used frequently if shared.
But I have heard of quite a few sites (over the years) being burned when
they said SHARED=NO and forgot to update when they instroduced multiple
systems.
--
Bruce A. Black
Senior Software Developer for FDR
Innovation Data Processing 973-890-7300
personal: [EMAIL PROTECTED]
sales info: [EMAIL PROTECTED]
tech support: [EMAIL PROTECTED]
web: www.innovationdp.fdr.com
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