Remove Volume Group

[Zean Wilmot_1]

Hi i have to disk which are at present mirrored and due to performance issue's and space need to be set to Raid 0+1 stripping and mirroring.

--- Physical volume groups ---
PVG Name -pv0
PV Name /dev/dsk/c6t8d0

PVG Name pv1
PV Name /dev/dsk/c4t8d0

what i need to to know do i simple pvremove the and vgremove them and recreate the stripe and mirror within these two disks.

Thanks Zean

[Sundar_7 · Accepted solution]

Hi Zean,

Stripping and mirroring you have with LVM is not a REAL stripping. But with only two disks you can only do striping. How are you going to mirror these two drives?. you need couple more for mirroring.

LVM has got something called "Extend Based Stripes" where the stripe size equals to that of the PE size. You can use -D option with lvcreate to create this Extend based stripe.

But you also should do your homework whether a stripe size of 4MB is going to help improve your application performance.


1) Backup the data
2) Remove all the logical volumes with lvremove
3) Remove c4t8d0 using vgreduce
4) vgremove the VG
5) Create the VG with these two disks and have the same PVG configuration
6) use -D and -s option with lvcreate while creating the LV. man lvcreate

Sundar

[Patrick Wallek]

With just 2 disks you CAN NOT stripe and mirror! You just don't have enough hardware. You can stripe OR mirror. NOT BOTH!

[SureshKumar_2]

Dear Zean

IT IS POSSIBLE - with what ever Hardware u have.

Follow the procedure as per SUnder
use the switch : -s n

with lvcreate, it will not allow strict allocation policy.

let me know, if any thing else

bye

suresh