On Fri, Jun 30, 2006 at 02:12:09AM -0700, Steve Bennett wrote: > > How did you measure it? (I'm not saying it doesn't > > take those 45kB - just I haven't checked it myself > > and I wonder how you checked it). > > ran 'top', looked at 'mem free' > created 1000 filesystems > ran 'top' again. > rebooted to be sure > ran 'top' again > > I'm sure I should use something better than top, but it does the job. > > I just repeated this and found that I was wrong on usage. 1000 filesystems > brought my free memory on a freshly booted system down from 856MB to 620MB. > I make 236KB per filesystem. If that's right, 10,000 mounts would eat 2.4GB of > memory.
It may be correct that having 1,000 filesystems mounted used up an average of 236k per filesystem on your machine. However, you can not necessarily extrapolate to more filesystems. Most of that memory is ZFS cached data which is evictable. So under memory pressure, we will throw it out and make room for more filesystems to be mounted (or files accessed, apps run, etc). That said, there is still some minimum amount of memory used, and we're working on reducing it. See bug 6425094 "each mounted filesystem requires too much memory". --matt _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
