Advanced - EMC Clariion, VNX

Troubleshooting

Snapshots are not being created

It is recommended that multiple SnapProtect backups using the same host must be run one after the other. Multiple SnapProtect backups running at the same time may cause the snapshot creation to fail due to the database lock.

Unable to perform cloning operation

For clone operations, ensure that Clone Private LUN (CPL) is created for each storage processor prior to performing the snapshot operations.

Clariion discovery command fails with error

The symcfg discover -clariion command fails with the following error:

Invalid certificate encountered - End-of-chain encountered without finding a trusted certificate

The discovery command fails because there is no LUN coming from the Clariion array to the proxy computer. To solve this issue, consider the following scenario:

If you have two storage arrays (Clariion 1 and Clariion 2) and a proxy computer, where the proxy has access to the LUN in Clariion 2 and your source LUN comes from Clariion 1. Clariion 1 does not have any LUN on the proxy. For the discovery operation to be successful, you must add a LUN to Clariion 1 and mount it to the proxy computer to allow connectivity. It is recommended to perform this workaround instead of using the Clariion discovery command.

FAQ

What should be the size of Free LUN?

Free LUN should be of the same size as the clone source and this LUN should not be a part of any storage group.

How to Assign a new LUN to a Specific Host?

Before you proceed to assign a new LUN, ensure the following:

Proper hardware zoning has been completed for the Hot Bus Adaptors (HBAs) of the server to provide visibility to a storage processor.
The NaviAgent is installed to allow connectivity to the Navisphere Server.

Follow the steps below:

1.	Allocate a new LUN.
2.	Select the Clariion system and host to be configured. You can either create a new RAID Group or use an existing one.
3.	Select a specific LUN parameter. You can also use the option for automatic configuration of the LUN ID to the host.
4.	Verify your selections and click Finish. Check that the specified LUN has been created under the correct Storage Group for the host.

How to Verify that a LUN is Mapped to a Host that Requires Protection ?

To check if the LUN is already assigned to the server, check the following under Navisphere:

1.	The LUN that was created based on the RAID Group must be present to the Host through Access Logix Storage Groups.
2.	From the Clariion Storage Group configuration, you should be able to see the LUN. For example, LUN 154 is based on RAID Group-0, which has RAID-5 configuration.

How does SnapProtect work with SnapView/Clone?

Calypso always runs a synchronization process to Clone target columns. The example on the right shows where the Clone SnapProtect job ran from Job ID #2748 from Navisphere. The example on the right also shows that the Clone is:

Consistent: Synchronization was completed.
Fractured: Clone is avialable to be mounted to the host (production or proxy computer).

Calypso uses the following naming convention for the SnapProtect jobs:

SP_<commcell id as per the CSDB>_<Job_ID>_XXX

When a SnapProtect job is running, you will notice that a synchronization is required for SnapView/Clone before the Clone can be fractured as shown in the example.

You must have enough space on the Clone target RAID group or enough Clone Private LUN for SnapProtect operations to run successfully.

How does SnapProtect work with SnapView/Snap?

Unlike Clones, SnapView/Snap does not need synchronization as it will copy any blocks that have been modified based on the Copy-On-Write model. Once a snapshot has been taken, you can see in Navisphere that a new snapshot was created as shown in the example on the right.

Calypso uses the following naming convention for the SnapProtect jobs:

SP_<commcell id as per the CSDB>_<Job_ID>_XXX_<Original LUN ID>

You will also notice that a Sessions that starts when the snapshot is created as seen in the image. Sessions are created based on the snapshot to allow:

Tracking on which snapshot the session is present and on which reserved or source volume.
Tracking of blocks that have been modified.

Once a snapshot has been activated to the host computer, it is available for the host that is specified with the Storage Group as shown in the example on the right.

Also, once the snapshots have been defined, they will remain inactive until they are activated again to run the SnapView session.

Best Practices

Ensure that the client and proxy computers are configured and have access to the array.
Ensure that sufficient number of Save Area devices are configured to meet your retention requirements.
Ensure that enough disk space is available for snapshot operations and the disk space used by snapshots is monitored. The space requirement for snapshots created during SnapProtect backup can vary based on your environment. The space utilization is dependent on the number of snapshots created and the retention period defined for the snapshots.
For any EMC Clariion operations to work, the SYMAPI_HOME_DIR registry key must be set to the directory where the Symmetrix SYMAPI library is located.
In order to use a specific initiator for accessing snapshots during SnapProtect backup set the sSNAP_UseINITIATOR registry key to the desired initiator address.