Drobo B800i Administrator Guide

Drobo How-To Guide
Migrating a Disk Pack Between Drobo iSCSI SAN Systems
drobo.com | Migrating a Disk Pack between Drobo iSCSI SAN systems
1
BeyondRAID™technology in Drobo enables users to quickly migrate the set of disks (referred to as a “disk pack”) in
one Drobo to a Drobo of the same model. Also, in certain cases, disk pack migration is supported from a smaller or
older Drobo to a larger or newer model.
Disk pack migration may be required when you need to replace a system or when you want to upgrade from an older
model such as DroboElite to a newer Drobo model B800i. This document uses the example of migrating a disk pack
from DroboElite to Drobo B800i, though these steps can be used to migrate a disk pack for B1200i.
The first section is universal to disk pack migration for supported paths. A list of supported paths can be found @
http://www.drobo.com/migration. If the Drobo is an iSCSI SAN model being used for VMware primary storage, then
additional steps are required, as detailed in the other sections in this document. These steps apply to any SAN
storage where a controller is changed, though Drobo does make it easier than most storage devices to get updated
and return to normal use.
Note: In most cases migrating drives is a one-way operation for supported migrations from one Drobo model to
another. Once a disk pack is migrated, you will no longer be able to access the data it contained with the older Drobo.
Topics
What will you need
Preparing for migration and moving the disk pack
Preparing to resignature volumes
Mounting VMFS datastores after migration
Connecting VMs to their disks
What You Will Need
•Source Drobo system and the new target system
•The most recent firmware installed on both Drobo devices
•The latest version Drobo Dashboard management software, minimum version 2.0 or higher
To download the latest version of firmware and Drobo Dashboard for your device, visit
http://www.drobo.com/support/updates.php.

Drobo How-To Guide
Migrating a Disk Pack Between Drobo iSCSI SAN Systems
drobo.com | Migrating a Disk Pack between Drobo iSCSI SAN systems
2
Preparing for Migration and Moving the Disk Pack
STEP 1
Shut down the existing
Drobo system. In Drobo
Dashboard, select
Tools > Shutdown
(circled in red).
Ensure that all lights
on the Drobo are off
before performing the
next step.
STEP 2
Now, simply remove
all of the drives from
the source Drobo.
Since Drobo is slot
independent, you don’t
need to keep track of
which drives came out
of which slots when
you re-insert them into
the destination Drobo.

Drobo How-To Guide
Migrating a Disk Pack Between Drobo iSCSI SAN Systems
drobo.com | Migrating a Disk Pack between Drobo iSCSI SAN systems
3
STEP 3
The IP address and other device settings such as the name are retained within the disk pack, so the destination
system will appear with the same name and IP address as it had in the source Drobo
Insert the disks from
source Drobo into the
new Drobo in any order.
Verify that all cables on
the destination Drobo
are plugged in and
power up the unit.
Drobo Dashboard
automatically discovers
the system.

Drobo How-To Guide
Migrating a Disk Pack Between Drobo iSCSI SAN Systems
drobo.com | Migrating a Disk Pack between Drobo iSCSI SAN systems
4
Preparing to Resignature Volumes
When a LUN is presented to an ESX/ESXi host, it gets a signature in the form of a Universally Unique Identifier
(UUID). This UUID uses the MAC address of the physical port and thus must be updated when the physical MAC
address changes after a disk pack migration. This process using the VMware command line will find “dead paths”
and update them as necessary.
STEP 1
Open a terminal session to the ESX/ESXi Server host and log in as root. If for any reason you are unable to connect to
an ESX/ESXi Server host via an SSH session, refer to the VMware KB article “Unable to connect to an ESX host using
Secure Shell (SSH) (1003807)” @ http://kb.vmware.com/kb/1003807.
STEP 2
Run the command:
esxcfg-mpath -L
|grep dead
This will return any “dead paths” that may have resulted from the disk pack migration due to a change in Universal
Unique ID (UUID). The ESX host uses a unique identifier to reference the volume. The name you specify when you
create a VMFS volume is a user-defined device name that is a symbolic link to the UUID of the VMFS volume (done to
solve the problem of changing the device name). When you change the volume name you are changing only the user-
defined device name and not the volume UUID.

Drobo How-To Guide
Migrating a Disk Pack Between Drobo iSCSI SAN Systems
drobo.com | Migrating a Disk Pack between Drobo iSCSI SAN systems
5
STEP 3
To perform ESX/ESXi
host rescan, run the
command esxcfg-
rescan vmhbaxx
where xx is the unique
ID, in this example, 33.
If any syntax is returned, it means that there is a dead path and you must reboot the ESX/ESXi host. If reboot is not
required, proceed to the next step.
STEP 4
To verify the all paths-
down (APD) state due
to a dead path, run
grep -ir "APD"
vmkerne
The APD state is a condition in which no working path exists to a storage device (LUN). In this case, it is a result of
migrating the disk pack from DroboElite to Drobo B800i. Reboot the ESX/ESXi host, ensuring that no VM is active
before rebooting.

Drobo How-To Guide
Migrating a Disk Pack Between Drobo iSCSI SAN Systems
drobo.com | Migrating a Disk Pack between Drobo iSCSI SAN systems
6
Mounting VMFS Datastores after Migration
As part of the disk pack migration process, LUNs from the Drobo will appear to VMware as snapshots. VMFS
datastores on your existing volumes detected by VMware as snapshot LUNs can be mounted using one of the
following options:
•Resignature the VMFS datastore and mount it on the selected host. Subsequent VMFS refresh is required on
other hosts to see this newly resignatured datastore.
•Keep the existing signature of the VMFS datastore and mount it on the selected host, also known as “force
mounting” a VMFS datastore.
The steps in this section describe the second option, keeping signature(s) of the VMFS datastore(s).
STEP 1
Connect directly to the ESX host service console, logging in as root
STEP 2
List the volume and
capture the UUID. Run
the command:
esxcfg-volume –
l
NOTE:The “Can mount” value must be “Yes” before you can proceed to the next step.
STEP 3
Record the UUID portion of the output to be used in the next step. In this example, one of the UUIDs is 4cbf6c94-
57b4c7f3-42bf-002219d4fc7f.
STEP 4
Run the command: esxcfg-volume -M <UUID>
Where <UUID> is the value recorded in Step 3.
NOTE: If you do not wish the volume mount to persist after reboot, use the –m switch instead.

Drobo How-To Guide
Migrating a Disk Pack Between Drobo iSCSI SAN Systems
drobo.com | Migrating a Disk Pack between Drobo iSCSI SAN systems
7
Connecting VMs to Their Disks
In any case in which the datastore fails to map to the VM after migration, use the following procedure to remap the
VMX files.
STEP 1
Connect directly to the ESX host service console, logging in as root.
STEP 2
List path and names of registered VM .vmx files on the current host. Run the command: vmware-cmd -l
STEP 3
Register the virtual machine from the ESX command line using:
vmware-cmd -s register
/vmfs/volumes/<datastore>/<virtual_machine_directory>/<virtual_machine_name>.
vmx
Where:
•<datastore>represents the datastore name
•<virtual_machine_directory>represents the directory containing the virtual machine files
•<virtual_machine_name>represents the name of the virtual machine files.
The following is an example:
vmware-cmd -s register /vmfs/volumes/Storage1/vm1/vm1.vmx
A return code =1 signals success.
Here is an example of using the VIM command:
#vim-cmd solo/registervm /vmfs/vol/datastore/dir/vm.vmx
Using the directory in the example above:
#vim-cmd solo/registerv /vmfs/volumes/Storage1/vm1/vm1.vmx
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Copyright 2012 Drobo, Inc. Data Robotics, Drobo, DroboEllite, DroboPro, BeyondRAID, and Smart Volumes are trademarks of
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All rights reserved. Specifications subject to change without notice. !HT-0028-01 !April 2012