Date: Tue, 24 Apr 2012 14:53:26 +0100 From: Johannes Totz <johannes@jo-t.de> To: freebsd-fs@freebsd.org Subject: Re: Increasing ZFS Disk Sizes Message-ID: <jn6b8m$3k5$1@dough.gmane.org> In-Reply-To: <4F964429.5060607@infracaninophile.co.uk> References: <CACMcHMdCaJjE1Ao7jN156tK%2ByNHDCyEZ-wam489jq2JhCJd%2BnA@mail.gmail.com> <4F964429.5060607@infracaninophile.co.uk>
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On 24/04/2012 07:11, Matthew Seaman wrote: > On 24/04/2012 04:22, Tim Gustafson wrote: >> Am I missing anything here, or is the this "safe" way to do this? Do >> I need to do anything special (other than the gpart bootcode command) >> to make the new disk bootable? Do I need to do anything special to >> set up the swap partition? Right now, I have this in my /etc/fstab: > > Yes, this is a good way to do this change. The only better way would be > to add the 2TB disk to the mirror first -- thus making a three way > mirror, let that resilver, and then remove one of the old drives. But > that requires you to have available spare disk slots. Don't forget to scrub first. Also might want to consider a zpool split, instead of detach. So that you have two disks with usable data in case the to-be-resilvered-from disk dies unexpectedly. > >> /dev/gptid/47bc37af-873b-11e1-b913-003048b98c9e none swap sw 0 0 >> >> Would it be safe to change that to: >> >> /dev/ada1p2 none swap sw 0 0 >> >> during the operation, and then back to ada0p2 when the re-silvering is complete? > > What does swapinfo(8) say? If your system is swapping directly to the > partitions on both those drives then you have some work to do. You > can't just pull a drive with an active swap area on it -- you should use > swapoff(8) to disable the swap area first. That's something that can > take some time, lots of IO and is not actually guaranteed to work; in > which case you may need to edit /etc/fstab and reboot to free up that > swap area. > > One thing I'd certainly recommend your doing here is to set up a gmirror > across your swap partitions. As it is, despite having your filesystems > mirrored using ZFS, you are still vulnerable to system crash should one > of your drives fail. To do that: > > Halt the system and reboot into single user mode (ie shutdown -r). You > want this so that your current swap partitions are not enabled, as > you'll need to modify their configuration. Add -- > > geom_mirror_load="YES" > > to /boot/loader.conf One time only, run 'kldload geom_mirror' for the > initial setup -- in future this will happen automatically. > > Create the mirrored swap by: > > # gmirror label -b load -F swap /dev/gpt/swap0 /dev/gpt/swap1 > > and then modify /etc/fstab so that the swap related line is like so: > > /dev/mirror/swap none swap sw 0 0 > > Then hit ^D to carry on booting as normal. > > Cheers, > > Matthew >
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