SUMMARY: Mirroring-striping with Veritas

From: Rasana Atreya (rasana_atreya@hotmail.com)
Date: Fri Oct 15 1999 - 14:59:19 CDT


Hi all,

Solaris 2.6, Veritas Volume Manager 3.0.1.

I had 2 disks which I had striped 2 way, and also mirrored (on another 2
disks). I got 4 additional disks which I wanted to add to the above setup in
a 4-way stripe and mirror. In addition I wanted to mirror-stripe (RAID 1+0)
instead of stripe-mirror (RAID 0+1) for greater reliability.

Turns out that mirror-stripe (RAID 1+0) is not supported as by Volume
Manager 3.0.1.

There might be better ways to do this, but here's what I did based on
manpages:

- I detached the mirror of each volume that was 2-way striped:
# vxplex -o rm dis vol02-02
# vxplex -o rm dis vol03-02
# vxplex -o rm dis vol04-02
# vxplex -o rm dis vol05-02

- I restriped the live volume 4-way from 2-way
# vxassist -v -b -g dskgrp_name relayout vol02 ncol=4 newdisk01 \
  newdisk02
# vxassist -v -b -g dskgrp_name relayout vol03 ncol=4 newdisk01 \
  newdisk02
# vxassist -v -b -g dskgrp_name relayout vol04 ncol=4 newdisk01 \
  newdisk02
# vxassist -v -b -g dskgrp_name relayout vol05 ncol=4 newdisk01 \
  newdisk02

The above took me more than 2 hours.

While this is going on:

- 'vxprint -tv' will show lots of intermediate volumes
- 'vxprint -h' will also show lots of intermediate volumes. In
  addition, it will say 'relayout'. This will disappear when it is
  done.

In addition the first command below will show freed up space, the second
will show some space has been used up in restriping:
# vxassist maxsize layout=stripe olddisk01 olddisk02
# vxassist maxsize layout=stripe newdisk01 newdisk02

I used this additional space to create the rest of the stripes:

# vxassist -g dskgrp_name -U fsgen make vol12 8833246s layout=stripe \
   nstripe=4 stripeunit=64 olddisk01 olddisk02 newdisk01 newdisk02
# vxassist -g dskgrp_name -U fsgen make vol13 8833246s layout=stripe \
   nstripe=4 stripeunit=64 olddisk01 olddisk02 newdisk01 newdisk02
# vxassist -g dskgrp_name -U fsgen make vol14 8833246s layout=stripe \
   nstripe=4 stripeunit=64 olddisk01 olddisk02 newdisk01 newdisk02
# vxassist -g dskgrp_name -U fsgen make vol15 8833246s layout=stripe \
   nstripe=4 stripeunit=64 olddisk01 olddisk02 newdisk01 newdisk02

- Then I recreated the mirrors for each of the striped volumes:
# vxassist -v -b -g dskgrp_name mirror vol02 layout=stripe nstripe=4 \
    olddisk03 olddisk04 newdisk03 newdisk04
# vxassist -v -b -g dskgrp_name mirror vol03 layout=stripe nstripe=4 \
    olddisk03 olddisk04 newdisk03 newdisk04
# vxassist -v -b -g dskgrp_name mirror vol04 layout=stripe nstripe=4 \
    olddisk03 olddisk04 newdisk03 newdisk04
# vxassist -v -b -g dskgrp_name mirror vol05 layout=stripe nstripe=4 \
    olddisk03 olddisk04 newdisk03 newdisk04
# vxassist -v -b -g dskgrp_name mirror vol12 layout=stripe nstripe=4 \
    olddisk03 olddisk04 newdisk03 newdisk04
# vxassist -v -b -g dskgrp_name mirror vol13 layout=stripe nstripe=4 \
    olddisk03 olddisk04 newdisk03 newdisk04
# vxassist -v -b -g dskgrp_name mirror vol14 layout=stripe nstripe=4 \
    olddisk03 olddisk04 newdisk03 newdisk04
# vxassist -v -b -g dskgrp_name mirror vol15 layout=stripe nstripe=4 \
    olddisk03 olddisk04 newdisk03 newdisk04

Thanks to the following for pointing me in the right direction. They pointed
out that Veritas does not support stripes of mirrors. In general once a
volume is created, it cannot be used in any other configuration. Mirror of
stripes is an exception.

DeQuoy, Peter
Viet_Q_Hoang
Luke A. Kanies
Roger B.A. Klorese

My thanks to all,
Rasana

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