Performance, too keep the Master Catalog, a major system bottleneck, small.
The alias directs the request to a usercat (Some.Catalog) which keeps the Master Catalog small. Usercats also facilitate subsystem isolation so that the user catalogs associated with certain subsystems can be backed up and restored in-sync with the data and individually since in a disaster recovery situation you probably will not restore absolutely everything. Also SYS1 datasets must be in the master cat. On Fri, Jul 9, 2010 at 2:45 PM, Charles Mills <[email protected]> wrote: > What is the reason for defining a catalog alias? I think I understand the > technical effect but I don't understand the big picture purpose. > > > > Suppose I wanted to define and catalog some new datasets FOO.THIS and > FOO.THAT. Why would I issue something like > > > > DEFINE ALIAS (NAME(FOO ) RELATE(SOME.CATALOG)) > > > > I understand the "little picture" reason: to specify FOO as an alias for > SOME.CATALOG but big picture, why would I not just create and catalog > FOO.THIS and FOO.THAT using JCL? What is the advantage of or reason for > defining the alias? > > > > Is there an overview somewhere of catalogs and catalog management? > > > > Thanks for your patience with an incredibly elementary question. > > > > Charles Mills > > > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: GET IBM-MAIN INFO > Search the archives at http://bama.ua.edu/archives/ibm-main.html > -- George Henke (C) 845 401 5614 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
