on 28/09/2010 19:46 Ben Kelly said the following: > Hmm. My server is currently idle with no I/O happening: > > kstat.zfs.misc.arcstats.c: 25165824 > kstat.zfs.misc.arcstats.c_max: 46137344 > kstat.zfs.misc.arcstats.size: 91863156 > > If what you say is true, this shouldn't happen, should it? This system is an > i386 machine with kmem max at 800M and arc set to 40M. This is running head > from April 6, 2010, so it is a bit old, though.
Well, your system is a bit old indeed. And the branch is unknown, so I can't really see what sources you have. And I am not sure if I'll be able to say anything about those sources. As to the numbers - yes, with current code I'd expect arcstats.size to go down to arcstats.c when there is no I/O. arc_reclaim_thread should do that. > At one point I had patches running on my system that triggered the pagedaemon > based on arc load and it did allow me to keep my arc below the max. Or at > least I thought it did. > > In any case, I've never really been able to wrap my head around the VFS layer > and how it interacts with zfs. So I'm more than willing to believe I'm > confused. Any insights are greatly appreciated. ARC is a ZFS private cache. ZFS doesn't use unified buffer/page cache. So ARC is not directly affected by pagedaemon. But this is not exactly VFS layer thing. -- Andriy Gapon _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "[email protected]"
