On 12 May 2017 at 18:45, Spencer Hayes <spencer@xxxxxxxxxxxxxx> wrote: > > We're attempting to run some performance tests on a Solaris 11.2 > system with ZFS. The system has a sizable amount of memory which is > currently more than the available space left in ZFS. Given that ZFS > does not provide for direct IO, we're looking for options on how to > exhaust the caching and actually test the throughput of the underlying > disks. If you're doing writes you can wait for synchronisation on stable media either at the end of periodically by using the sync / fsync options. For reads... well I guess you can start from an empty cache by unmounting/remounting the filesystem before starting your tests? I'm not sure you want to test a filesystem for non-cached I/O performance unless your application is going to somehow depend on it though. > I've looked through several of the fio options but so far have not > been able to find a mix that would let us do more total IO than is > actually used as space on disk. The idea we had was to lay down say a > 100GB file, but do 200-300GB of actual IO within that single (or > multiple) file(s). You probably want to use size with offset and io_size/loops (see http://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-size , http://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-offset , http://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-io-size , http://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-loops ) > Does anyone have experience perf testing ZFS and might have some > suggestions to tackle this scenario? You might get some good suggestions on a Solaris related ZFS mailing list - https://illumos.topicbox.com/groups/zfs/discussions . -- Sitsofe | http://sucs.org/~sits/ -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
