On Tue, 17 Oct 2006 10:16:41 -0500, McKown, John <[EMAIL PROTECTED]> wrote:
>> >> >> We're about to IPL our new Z machine and the discussion >> turned to MIM and the fact that the LPAR about to be IPL'd >> won't be protected. We have shared DASD and shared User >> Catalogs. SHROPTIONS are defined as (3,4). >> >> Are we exposing ourselves to any risk of catalog corruption? >> >> TIA, >> Dave O'Brien > >No. I run that way all the time between my production and sandbox LPARs. >The CATALOG code has special code so that sharing can occur without >corruption even without something like MIM or GRS or Sysplex sharing of >ENQs. > The special code that you are probably thinking of has to do with managing cache (ISC or VLF) and has nothing to do with protection. Protection is accomplished with RESERVE unless something converts the RESERVEs to global ENQs. More below... > >> > >> -----------------------<unsnip>-------------------- >> Yes, you are. Some sort of serialization/synchronizing >> product is just >> about mandatory for all the images sharing that DASD farm. >> If only sharing catalogs, it would depend.... see below. > >I agree that, in general, corruption of datasets can occur. But I must >disagree that a CATALOG could be corrupted. Perhaps a DFP person will >clarify. I know that I have run without any cross-system serialization >product for a long time with no CATALOG corruption. > That is probably because you let your RESERVEs remain as RESERVEs or you are just lucky. If you have a GRSplex or a MIIplex and convert SYSIGGV2 (** which goes against the grs ring or MII without the control file in a CF recommendation) from a RESERVE to a global ENQ and then share the catalogs with a system that is not part of the plex, you are in danger. The system not in the plex will reserve the catalog when needed but nothing will stop that system from updating the catlog while the systems in the GRSplex/MIIplex may be updating it. ** Note that with GRS star or MII with a CF control file, many shops are converting all reserves to global ENQs (this is required for GDPS BTW), so IPLing a system sharing the catalogs into that environment that is not part of the integrity manager plex could lead to corruption. Mark -- Mark Zelden Sr. Software and Systems Architect - z/OS Team Lead Zurich North America / Farmers Insurance Group - GITO mailto:[EMAIL PROTECTED] z/OS and OS390 expert at http://searchDataCenter.com/ateExperts/ Mark's MVS Utilities: http://home.flash.net/~mzelden/mvsutil.html ---------------------------------------------------------------------- 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
