We're planning to migrate a disk storage subsystem (AAA - scsi) to another
vendor (BBB - fcal). AAA currently is connected to an UE6000 via 8 UW-scsi
HBA's to 4 SBus I/O boards. The 4 Sbus I/O boards currently has 3 available
Sbus slots to which we plan to initially connect the new storage BBB via
FC-AL for the data migration. All of BBB's disk devices will initially be
LUN configured to be distributed to the 3 FC-AL after which the FC-AL
channels will be increased to 6 or more when AAA is finally detached as well
as its controllers. BBB will then be reconfigured to non-destructively
re-allocate the LUN's among the bigger number of FC-AL's (Not sure here...
is this possible?)

My question then is, after I have added and re-distributed the FC-AL
controllers among the I/O boards to reflect the higher number of FC-AL
channels, will VXVM be able to maintain the migrated diskgroups and its
associated volumes? Assuming that on the new subsystem BBB, non-destructive
re-allocation of the LUN's (disks) among the new number of FC-AL channels is
successful?

(root/swap/usr disks are not under VXVM control/non-encapsulated)
AAA:  rootdg (1 small disk no volumes)  diskgrp01 (104 disks, volumes...)

The tentative procedure I am thinking of is as follows:

1. Shutdown system, install FC-AL HBA's on the 3 slots, install drivers
2. Reboot single user, invoke format to check BBB's devices, label them
3. Migrate rootdg. Add disk from BBB name it rbbb01
4. Remove AAA's disk from rootdg to finally migrate rootdg
5. Add all remaning BBB's disks to diskgrp01 naming the disks bbb01-bbbNN
6. Mirror each Volume on diskgrp01 accordingly, (many hours???)
7. After mirrors are synched, detach plexes belonging to AAA on each volume
8. Remove AAA's disks in diskgrp01. All data is now migrated to BBB at this
point.
9. Check volumes, check filesystems...
10. Do a touch /reconfigure. Shut down system to remove AAA and its scsi
HBA's
11. Repopulate FC-AL's on the I/O boards. 3 FC-AL now becomes 6 or more
    (additional I/O boards may be added.)
12. On BBB, reconfigure the LUN's to re-allocate disks to the new number of
    FC-AL channels. (Can this be done nn-destrutively??? so all VXVM configs
    are maintained??)
13. Reconnect BBB. Restart the system.. VXVM configs should be maintained
14. Health checks...done?

I am particularly unsure after steps 11-13 if the system will still be able
to recognise the disks as for sure the addresses will change. Will I need to
do a 'devlinks' then 'disks' or it's no longer necessary since I've already
done a /reconfigure prior to shutdown?  Also, I am not at all 100% sure
whether BBB (or any of todays storage subsystems) can do a non-destructive
LUN re-allocation among the I/O channels.

Any insights, corrections experiences will be appreciated.

Thanks in advance and as usual, I will summarise.

------------------------------------------------------------------
NELSON CAPARROSO y TAN
UNIX/Microsoft/GIS Consultant
Decision Consultants, Inc

Internet  :  www.decisionconsultants.com
             nelson.caparr...@decisionconsultants.com

Disclaimer:  All views & opinions in this e-mail are mine alone!
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