There is no rule of thumb. It's very likely that 16M is way too small, but we're not likely to change the default. 128M is fairly common, I believe.
It's not necessarily the case that a bigger size is better. The more data that is cached, the more likely you are to be able to retrieve from the cache (which is a good thing) but the longer it may take to locate the data (which is not a good thing). In the distant past some found that sizes of 256M and above were detrimental. But no one that I know of actually did any analysis to try to figure out "why". The guess was that the performance decrease correlated to the number of objects that then were cached. It has probably been well over 10 years since I last heard any discussion of this; I have no idea if what was seen was typical or "one-off", or if it still behaves that way. Peter Relson z/OS Core Technology Design ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
