Is there anything in the transition between z/VM 5.3 SLU 0702 and z/VM 5. 4 SLU 0801 that would negatively impact MDC's use of real storage in favor
of guest storage? I noticed in a recent ESAMDC report that the average size of MDC had plummeted from what it normally has been. Looking back through my historical data I see that it happened on the day and time that I migrate d from z/VM 5.3 to z/VM 5.4 (11/30/2008). MDC is in real storage only, non e in XSTORE. All MDCACHE parameters are the same as is the storage/xstore for the LPAR and vstor for the Linux guests. The MDC objective size has not changed in the reports and are way above the average MDC size. Page rates are still typically at or near zero, but the reported MDC Steals/se c has gone from near zero to the 40-70 range with prolonged intervals of 20 0- 300 and some as high as 700/sec. The ESAUSR2 report shows total resident pages for guests has increased by about the same amount as MDC storage has decreased, and it seems to be spread out across all guests, which are mostly SUSE Linux. The number of locked pages is about the same. The number of VDISK pages in real storag e is also about the same. The page rate to/from xstor is way down, which makes sense since the guests have more pages resident in real storage. I'm just not sure why C P is now favoring guest storage more at the expense of MDC than it used to. It doesn't appear to be an IPL related phenomenon, as the data across a prior IPL of z/VM 5.3 shows consistent behavior. If it's not a z/VM release related issue what else should I look at/for? Brian Nielsen
