Date: Sat, 11 Oct 2008 21:28:29 -0400 From: Mike Meyer <mwm-keyword-freebsdhackers2.e313df@mired.org> To: Jeremy Chadwick <koitsu@FreeBSD.org> Cc: freebsd-hackers@freebsd.org, Mike Meyer <mwm-keyword-freebsdhackers2.e313df@mired.org> Subject: Re: continuous backup solution for FreeBSD Message-ID: <20081011212829.57b889d7@bhuda.mired.org> In-Reply-To: <20081011112431.GA60924@icarus.home.lan> References: <20081010023428.87556dt18ejyzf48@mail.ispro.net> <20081009200641.60d0b236@bhuda.mired.org> <48EF5052.2000707@ispro.net> <20081010144111.GA34609@icarus.home.lan> <20081010112952.52b8209b@bhuda.mired.org> <20081010154249.GA35859@icarus.home.lan> <20081010122228.355c2c3e@bhuda.mired.org> <E1Koboa-000CyO-8l@cs1.cs.huji.ac.il> <20081011104409.GA58698@icarus.home.lan> <E1KocK0-000DEX-PV@cs1.cs.huji.ac.il> <20081011112431.GA60924@icarus.home.lan>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sat, 11 Oct 2008 04:24:31 -0700
Jeremy Chadwick <koitsu@FreeBSD.org> wrote:
> > I'm asking, because I want to deploy some zfs fileservers soon, and so
> > far the solution is either PXE boot, or keep one disk UFS (or boot off a USB)
> > Today's /(root+usr) is somewhere between .5 to 1Gb(kernel+debug+src),
> > and is readonly, so having 1 disk UFS seems to be a pitty.
>
> Hold on a minute. "One disk" has nothing to do with the filesystem.
> You asked if FreeBSD could boot off of a specific filesystem, and I
> answered that -- I didn't state anything about disk counts. Now you're
> changing the focus. :-)
>
> I'm pretty sure FreeBSD can boot off of gmirror setups (see above,
> boot2/loader should work off of gmirror), which means >1 disk. You
> do not have to gmirror the entire disk, you can gmirror just a slice
> (AFAIK).
>
> I think (hope?) you can use the "remaining" (e.g. non-UFS/non-gmirror)
> part of the 2nd disk for ZFS as well, otherwise the space would go
> to waste. The "Root on ZFS configuration" FreeBSD ZFS Wiki page
> seems to imply you can.
You mean like this:
bhuda% gmirror status
Name Status Components
mirror/boot COMPLETE ad0s1a
ad1s1a
bhuda% zpool status
pool: internal
state: ONLINE
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
internal ONLINE 0 0 0
mirror ONLINE 0 0 0
ad0s1d ONLINE 0 0 0
ad1s1d ONLINE 0 0 0
errors: No known data errors
Yes, I don't get the benefits of having /boot on a zfs partition, but
I do get the benefits of having it on a mirror: automatic duplication,
reads from either device, and I can use either device stand-alone if I
break the mirror.
Note that FreeBSD booting from a gmirror'ed partition/disk can't boot
from the gmirror device - boot doesn't understand gmirror. It can,
however, boot from any of the devices participating in the mirror. The
mirror device appears after the kernel is loaded.
Given that I have to have a separate boot partition, having swap
partitions on the drives is a win compared to swapping to a zvol. I'm
going to investigate putting /boot on an SSD of some kind so that ZFS
can have the entire disk.
<mike
--
Mike Meyer <mwm@mired.org> http://www.mired.org/consulting.html
Independent Network/Unix/Perforce consultant, email for more information.
O< ascii ribbon campaign - stop html mail - www.asciiribbon.org
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20081011212829.57b889d7>