I think that minute-by-minute usage of main memory could be accounted for in the same manor as CPU can be done if you start with the MONITOR data instead of the ACCOUNTING data. I think the current ACCOUNTING data is insufficient for a good chargeback system. Although with today's LINUX workloads with each linux system wanting to use ALL of its memory definition, you could charge for the definition of memory because that is the potential for impact on the system in main memory use and paging area requirements. So add something to your accounting to indicate that one day a linux system used 3/4 GB memory definition, and 1 GB the next day and two weeks later they wanted more and got bumped up to 1 1/2 GB, etc. Charge them at each increment. In the same vein, you should not charge a user for how much of a minidisk they really use, charge them for the whole allocation and for changes in the allocation. Although these 'allocation' charges do not reflect true usage, they do account for a level of system management that is required to maintain the system for the user and therefore are valid for charging.
/Tom Kern Rob van der Heij wrote: > Writing code to process VM account records is only part of the job > (and doing it in such a way that the auditors accept it to feed into > the company's financial systems is probably the hardest part of it). > Unfortunately account records don't provide data on main memory usage > (the hardest part with Linux on z/VM right now). You probably need the > performance monitor to help you out there. > > But in every installation where I have seen usage based accounting, > customers argued the validity because they "had not done anything > special to justify the increased charges" And pointing at a virtual > 80-column punch card with numbers does not convince them. It is very > helpful at that point to have reports of the performance monitor so > you can tell them exactly which user started what process in Linux and > how long it ran and what it used. > > One installation found it very educational to have a online per-minute > overview of the charges per server (or group of servers). It showed > the application developers why we told them to use a text-based > installer rather than the GUI-based, for example. > > Rob
