grew raid6 how do I extend vol group?

lil_delta · 05-16-2010, 12:13 PM

I'm running debian and used mdadm to setup up a raid 6 array with 4x1TB drives with roughly 1.86TB's available with lvm. Then I added 4x1TB drives to the array. So now I have an 8 drive raid 6 array with 5.+TB's available, the array sees all available space. The question is how do I extend the volume group so that it uses the whole raid and not just half of it. As of right now the volume group is only 1.86TB's.

In advance thanks for any insight.

exceed1 · 05-16-2010, 04:37 PM

you created new metadisk devices when adding the devices right? then just use the vgextend utility to extend it.. the usage of vgextend is pretty simple, just have a look in the manual

lil_delta · 05-17-2010, 01:12 AM

I'm not sure what metadisk devices mean.... could you elaborate. And I thought vgextend looked pretty easy but would not work. I read the man pages and several results off of google. Also a quick note... lvextend has the option to extend the volume to %FREE does vgextend have the same options (as it reads it doesn't i think).
Thanks for any help.

chrism01 · 05-17-2010, 06:08 AM

Try

cat /proc/mdstat

mdadm --detail

If you've successfully added the extra disks to the one RAID6 device, its probably called /dev/md0 (zero there), so

mdadm --detail /dev/md0

should confirm as would the cat cmd above.
If it's already there, you may be able to lvextend immediately, then resize2fs.

exceed1 · 05-17-2010, 01:49 PM

Quote:

Originally Posted by lil_delta

I'm not sure what metadisk devices mean.... could you elaborate. And I thought vgextend looked pretty easy but would not work. I read the man pages and several results off of google. Also a quick note... lvextend has the option to extend the volume to %FREE does vgextend have the same options (as it reads it doesn't i think).
Thanks for any help.

Hi

when looking at /dev/mdXX the "md" is short for "metadisk".
that being said, if you have your new devices under /dev/mdX you should be able to use vgextend /dev/mdx or similar.. i would recommend doing this instead of adding them directly into a logical volume as it gives you more flexibility and im not sure if you can add raw raid devices directly into an LV

lil_delta · 05-18-2010, 04:16 PM

alright I can't check that stuff just yet but i will later tonight... but I know that the raid array (mine is called md1) has been extended and is displaying 5.46TB's. So that means I should beable to just do a lvextend... if so what would the command be to extend it making it consume the new space of the array? Because it's not like i added another drive to the lv but the drive has been grown...(if that makes sense).
Thanks

ps ill post some screen shots later tonight.

chrism01 · 05-18-2010, 07:31 PM

http://tldp.org/HOWTO/LVM-HOWTO/extendlv.html