Increasing ZFS Disk Sizes

[Johannes Totz]

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
>