Re: [perf-discuss] zfs filebench: cached workload versus uncached workload

2009-04-28 Thread Andrew Wilson
Thanks for the clarification. Anyway, to Dearl Neal's point, you won't see much (if any) difference between cached and not cached in zfs, until the next release, because it is fs_flush that does the deed, and that is always called at present. Incidentally, I have an action item to come up w

Re: [perf-discuss] zfs filebench: cached workload versus uncached workload

2009-04-28 Thread johansen
On Tue, Apr 28, 2009 at 12:58:25PM -0700, Andrew Wilson wrote: > I believe that Solaris always converts reads and writes into file mapped > I/O, so if the cached attribute is missing or set to "false" the VM pages > involved in that will be flushed, so you will see a small difference in > perfor

Re: [perf-discuss] zfs filebench: cached workload versus uncached workload

2009-04-28 Thread Andrew Wilson
Since zfs uses a private cache (the ARC) for most of its file caching, rather than VM pages, the "caching" or not doesn't make that much difference. On the other hand, ufs does use VM pages, so the caching options makes quite a bit of difference. The fs_flush script is used to flush the ZFS