Repost: Migrate RAID5 to RAID10 on CERC SATA1.5/6ch RAID controller? [SOLVED]

David Kinnvall david.kinnvall at alertir.com
Thu May 13 08:18:00 CDT 2004


Following up myself. See below, inline, for details.

(Dell provided zero assistance in this matter, but I
 decided to give it a shot anyway. Summary: It works.)

David Kinnvall wrote:

> Hi all,
> 
> CERC SATA1.5/6ch RAID in a PE700, using aacraid under RHEL3:
> 
> According to docs, it should be possible to migrate an existing
> RAID5 array to become a RAID10, without recreating from scratch,
> i.e migrating online. Anybody knows the exact steps using afacli
> or the BIOS panels for this?

Not possible using BIOS, but possible using afacli:

Setup at beginning:
- PowerEdge 700 with CERC SATA 6ch RAID controller, to which
  3 250GB disks are connected in a RAID5 configuration.

Ordered new disk on Monday, arrived today (Thursday).

Steps to install and configure disk:
- Just physically install it using already prepared cabling
  in the PE700 (four connectors) and start the machine.
- Don't do anything in the BIOS.
- Boot Linux (single user for me, probably not needed), then
  start afacli and perform the following steps, adjusted for
  any differences in your particular setup:

# Connect to the controller
open afa0
# Verify that the new, fourth disk is there, and UNinitialized
disk list
# Initialize (prepare) it - fourth disk, lives at (0,3,0)
disk initialize (0,3,0)
# Verify it being initialized
disk list
# Check the existing RAID5 container (should be nr 0)
container list
# Reconfigure, online, the RAID5 container (nr 0) to become
# a RAID10, utilizing the new fourth disk (0,3,0) to do it
reconfigure /raid10 0 (0,3,0)
# Check that the task is started and underway
task list
# Check the new RAID10 config
container list
# Wait a looong time for the task to complete, mine has
# been going for ~10 minutes and is at 0.8%, so it will
# take some time. But with 4*250GB disks, I guess that's
# to be expected

Adjust the above depending on your particular setup.

To summarize:
- It is possible to do this using afacli
- It is actually *very* easy
- It does take a long time, at least with large disks
- It does not require a reinstall and is done online
- I have no idea what the performance impact is on any
  running applications, since I prefered to do it in
  single user mode with nothing else running, but I would
  guess that the impact is significant, so if you do it,
  do it during off-peak hours (duh...)
- DO MAKE A BACKUP ANYWAY, AS ALWAYS!!

1.0% complete now, yay! :-)

/David




More information about the Linux-PowerEdge mailing list