You would in theory as from what i remember every zfs filesystem takes up 64 kb of ram, so the savings could be massive 8)
On 16 July 2013 10:41, Shane Ambler <free...@shaneware.biz> wrote: > On 16/07/2013 14:41, aurfalien wrote: > >> >> On Jul 15, 2013, at 9:23 PM, Warren Block wrote: >> >> On Mon, 15 Jul 2013, aurfalien wrote: >>> >>> ... thats the question :) >>>> >>>> At any rate, I'm building a rather large 100+TB NAS using ZFS. >>>> >>>> However for my OS, should I also ZFS or simply gmirror as I've a >>>> dedicated pair of 256GB SSD drives for it. I didn't ask for SSD >>>> sys drives, this system just came with em. >>>> >>>> This is more of a best practices q. >>>> >>> >>> ZFS has data integrity checking, gmirror has low RAM overhead. >>> gmirror is, at present, restricted to MBR partitioning due to >>> metadata conflicts with GPT, so 2TB is the maximum size. >>> >>> Best practices... depends on your use. gmirror for the system >>> leaves more RAM for ZFS. >>> >> >> Perfect, thanks Warren. >> >> Just what I was looking for. >> > > I doubt that you would save any ram having the os on a non-zfs drive as > you will already be using zfs chances are that non-zfs drives would only > increase ram usage by adding a second cache. zfs uses it's own cache > system and isn't going to share it's cache with other system managed > drives. I'm not actually certain if the system cache still sits above > zfs cache or not, I think I read it bypasses the traditional drive cache. > > For zfs cache you can set the max usage by adjusting vfs.zfs.arc_max > that is a system wide setting and isn't going to increase if you have > two zpools. > > Tip: set the arc_max value - by default zfs will use all physical ram > for cache, set it to be sure you have enough ram left for any services > you want running. > > Have you considered using one or both SSD drives with zfs? They can be > added as cache or log devices to help performance. > See man zpool under Intent Log and Cache Devices. > > > ______________________________**_________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/**mailman/listinfo/freebsd-**questions<http://lists.freebsd.org/mailman/listinfo/freebsd-questions> > To unsubscribe, send any mail to "freebsd-questions-** > unsubscr...@freebsd.org <freebsd-questions-unsubscr...@freebsd.org>" > _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
