Johansen, Correct me if I am wrong. If the applications request memory from O/S, the kernel will cut back ZFS cache - so in this sense the cache is free, right?
Yes ZFS cache is considered kernel memory, but as long as kenel will cut back its size and give back to applications, it'll be considered free. Yes ZFS cahce is in use, but so is UFS filesystem cache. I am not sure what you meant by "how much memory is wasted due to fragmentation", but if they are really wasted, then it's something else to enhance. One way or another, on any given system with ZFS, there must be a certain size of cache memory that can be given back - if we can track the number with a reasonable amount of effort and reflect it in vmstat output or with some other tool that does not require "mdb -k" I would think it's worthwhile. Just imagine this: for 9 years many people have been relying on either vmstat or kstat variables to report an almost usable Solaris memory utilization and now they just go back to report a steady 95% full memory stat, that can cause lots of troubles - For example, capacity management, especially in today's virualized environment. -- This message posted from opensolaris.org _______________________________________________ perf-discuss mailing list perf-discuss@opensolaris.org
