Exporting/Importing RAID disks

[JHL_1]

I currently have three banks of Raid (Raid-5) configured horizontally on three SC-10s connected to an FC-60. I'm wanting to add two more banks below these for a total of 5 horizontal banks. With only 3 banks currently, the luns are connected horizontally with 5 drives per lun for a total of 6 luns (2 per horizontal bank).

Ideally, 5-drive luns would be better configured vertically as each drive would be then be on a seperate controller. I am familiar with exporting/importing internal and jbod disks to/from different slots both vertically horizontally and a combination of both. Doing this is simple as I can simply look at the ioscan both before and after, see the difference and apply the new drive info to the vgimport.

BUT, for my HP RAID drives, my ioscans only show 4 of the five drives on each lun!

So:

First - can vgexport/vgimport be done on SC-10 RAID-5 drives?
Second - How do I determine the valid drive configurations if my ioscan only shows 4 of the five drives? (I've looked at Sam and done the math - the luns are really 5 drives).

When done, I'd like to finally have each lun configured with 5 drives vertically, and can I see all five drives on the ioscan?

Thanks so much.

[Varghese Mathew]

Hi,

Answering to ur first question yes vgimport is posible on ur config., anyway make sure that u have the backup of data on data before touching that.
The second question, looks like something strange as you are not getting the hard disks detected using ioscan command, but the sam shows the missing one too, take extreme care as SAM is not not showing the alternate path name (maye be one of your drive has got two paths - i am not sure how it happens).

Make sure that the lun which is missing is configured with the ownership (SPU) also, and your array has been configured with SPU switch over is enabled , as the ownership needs to be there for a disk (LUN) which is getting created ...

Hope this helps,
Cheers !!!
MAthew

[Bill McNAMARA_1]

I currently have three banks of Raid (Raid-5) configured horizontally on three SC-10s connected to an FC-60.
> Your FC60 is possibly in
> split bus mode. Thus 2
> disks are on the same bus
> and there will be 'slight'
> perf problems due to that..
> but the main pb is the spof
> of the SC10...

I'm wanting to add two more banks below these for a total of 5 horizontal banks. With only 3 banks currently, the luns are connected horizontally with 5 drives per lun for a total of 6 luns (2 per horizontal bank).
> in this case you'll be in
> full bus mode and perf will
> decrease slightly because
> you now have 5 disks per
> bus.. if your sc10's.. you
> can have up to 6 disks/bus
> in this config.
> But.. within the same lun
> balancing your lun disks
> across sc10's will increase
> your perf and capacity
> to a large extent overall

Ideally, 5-drive luns would be better configured vertically as each drive would be then be on a seperate controller.
> yes..
>

I am familiar with exporting/importing internal and jbod disks to/from different slots both vertically horizontally and a combination of both.
> no that's data migration.
>a vgimport and export
> only moves the vg from
> one host to another not
> from one disk to another.
> it also allows you to
> create other vgs.
> your pvs are still the same
> your pvs are the luns.. and
> you want to redistribute
> your luns, not your vg..

Doing this is simple as I can simply look at the ioscan both before and after, see the difference and apply the new drive info to the vgimport.
> nope.

BUT, for my HP RAID drives, my ioscans only show 4 of the five drives on each lun!
> ioscan will not show you
> drives.. it'll show you
> luns. the drive info is
> found from amdsp -l
>It is not recommended to
> move disks around sc10
>enclosures also.
> you should recreate your luns
>which will mean losing your
>data on the luns.
> backup/restore will be
> what hp would recommend..
> unless there's a move lun
> command I don't know about.
> you should get in touch
> with your CE/RCE/Sales when
> buying the new SC10s..
> I'm sure they'll do the task
> correctly and quickly..
> but if you want more info..
> you're always welcome here.

So:

First - can vgexport/vgimport be done on SC-10 RAID-5 drives?
> yes, but the data will not
> move from one disk to
> another disk in the sc10.
> it's just that the host
> the device file for the lun
> is the device file for the
> disk in the ioscan. the
> lun has more than one
> physical disk in it, but
>as far as lvm is concerned
> it is one physical volume.
> lvm doesn't even know it's
>raid protected.

Second - How do I determine the valid drive configurations if my ioscan only shows 4 of the five drives?
> you can't from ioscan.
>
(I've looked at Sam and done the math - the luns are really 5 drives).
> yes, a pv is not a physical
> disk in the case of raid
> systems it is a collection
> of disks seen as one ie a lun..

When done, I'd like to finally have each lun configured with 5 drives vertically, and can I see all five drives on the ioscan?
> ioscan no.. use sam, or
> amdsp -l
> the reconfiguring of the
> lun must be done by backup
> restore. it can't be done
> online to the best of my
> knowledge.. this is an lvm
> limitation not the fc60.
> on pvcreate of the lun the
> size is determined.

Thanks so much.
> you're welcome.
> good luck.
> and a backup is still a good
> idea to have when reconfiguring
> so there's no real harm
> anyway, come to think of it.

Later,
Bill

[JHL_1]

More info. Yes, the 3 horizontal banks are split bus. What I expect to do is have a total of 5 horizontal banks with full bus. That can be done but the remaining question is how do I move a 5-disk horizontal volume group to a 5 disk vertical volume group.

Using a single volume group as an example, I'd like to do the following:

Run vgexport for the volume group.
Remove the 5 drive (that are now horozontal)
Insert them vertically
Determine what the new device file names are
Run vgimport for the SAME volume group on these SAME drives. They are the same drives now just connected vertically.

Ok, but is this possible?
(1) Run vgexport/vgimport on RAID-5 Drives on an SC-10
(2) Remove them from a currently-configured split bus mode.
(3) Insert them vertically into 5 full-bus SC-10s
(4) Run vgimport for these same drives.

Man, I know this is a lot but I'm tryin' to be as clear as possible.

Thanks

[JHL_1]

Sorry guys if my questions are confusing. Here's an example of how I'm hoping it will look both before and after:

Before

00 01 02 03 04 05 06 07 08 09
10 11 12 13 14 15 16 17 18 19
20 21 22 23 24 25 26 27 28 29
XX XX XX XX XX XX XX XX XX XX
XX XX XX XX XX XX XX XX XX XX

After:

00 05 10 15 20 25 XX XX XX XX
01 06 11 16 21 26 XX XX XX XX
02 07 12 17 22 27 XX XX XX XX
03 08 13 18 23 28 XX XX XX XX
04 09 14 19 24 29 XX XX XX XX

For example:

In the case of vg01 (drives 00-04) These will be taken out of the top row and moved vertically. Again, these are the same physical drives and the volume group name will remain the same. I'm just concerned about hardware paths etc. and if it can be done on RAID. I'm getting very conflicting reports on if/how this can be done.

Again, any help is appreciated

[Varghese Mathew]

Hi John,

No you can't do this without loosing your data -

Check out this link

http://www.hp.com/cposupport/information_storage/support_doc/lpg30002.html#P5_423

You need to do a lot of rework on your VG's for doing eaxctly as what you have wanted for.

Cheers !!!
Mathew

[JHL_1]

Does this include SC-10s used as internal disks (not Raid)? The same disks and volume groups will be used both for the export and the import. The only change will be where on the SC-10s the disks are located.

Thanks a bunch - John

[Soren Morton]

John,

I highly doubt this will work because the FC60 will not understand what you are trying to do.

The FC60 controller would have to determine that you are re-configuring the LUNS (which the controllers in the FC60 creates, accesses and uses to retreive your data.). I don't think the FC60 is quite advanced enough to figure out what you are doing when you shuffle the disks.

If the controller did not perform the RAID activity for you then exporting and importing the volume groups would be possible since that data would be stored on the disk for the vgimport command to use, but this is not how it works with any hardware RAID device.

[Soren Morton]

John,

Yes, you can move drives on an SC10 without a restore if you are not/have not used the FC60 controller.

[JHL_1]

How they were configured - simply went into SAM and built the luns, file systems etc. These are connected to an FC-60 and via sam, when the luns were configured the menu choice for finding the drives was via the FC-60 menu item (which gives you the disk matrix.

If you have any more information I'd appreciate it. I was told by HP during an LVM course I took earlier this month that it could be done but when I went into specifics (like above) they then backed away and said to call tech support.