In our shop, we have Linux guest machines defined as dedicated volumes (this
was a holdover from the days before we got z/VM). Some other Linux machines
are also using full-pack minidisks.
Is there an advantage to using one over the other? What about performance?
Fullpack minidisks are potentially eligible for MDC. Dedicated volumes aren't
AFAIK. There are also some optimizations that are available to DEVNO and
dedicated devices that aren't available to minidisks, but I'm not sure it's
worth the management hassle unless you're doing really tight deadline OLTP.
Re: performance - on modern hardware, the difference is still measurable, but
it's a lot smaller than it used to be. Use your performance monitor to see what
it's like on your box.
Now that you have VM, start using cyl 1 to x minidisks and let VM worry
about the labels and real cyl 0. Makes DR and rearranging disk ENORMOUSLY
easier.
