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External storage must support SCSI-3 PR.
Volume should be configured by LUN(Logical Unit Number) unit. Partitioned volume in a LUN is not supported.If use PrType 3, at least 1GByte LUN is needed for key reservation.

Types of Shared disk resource

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2. Both the shared disk agent and the SCSI reservation agent can read and write data.
However, a SCSI reservation agent intends to protect the shared storage resource, so you are not recommended to use it alone to read and write data.
Thus, a SCSI reservation agent can be used together with a shared storage agent or can use a separate LUN from the shared storage (PrType option). 

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PrType (Persist Type) 1 : Type1 controls 'Write" of LUN. When use this option, shared disk resource can be used as lock disk. (Exclusive Write)

PrType (Persist Type) 3 : Typ3 controls "Access" of LUN. When use this option, exclusive LUN is needed for lock disk

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Configuration

There are two different ways to configure the SCSI reservation agent resource and the shared disk agents resource. It depends on the attribute of the SCSI reservation agent resource.

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1. When shared disk and SCSI Lock resource is configured with the same LUN (PrType=1)In the SCSI reservation agent resource, use the option of PrType = 1. In this case, LUN will be used to configure the shared disk resource and the SCSI reservation resource.

A shared disk agent uses the MVL driver to manage DATA-DISK and a SCSI reservation agent uses the SCSI3-PR function to manage LOCK-DISK.
By setting the dependency between the SCSI reservation resource and the shared disk resource, you can prevent damages to DATA-DISK caused by Split-Brains and so on.

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[Figure] Shared disk and SCSI Lock resource configured in same LUN (PrType=1)2. Shared disk and SCSI lock resource is configured with different LUN (PrType=3)

A shared disk agent manages DATA-DISK on the single drive character basis, and a SCSI reservation agent manages the standalone LUN exclusively for LOCK-DISK.
For this configuration, there must be at least two LUN segments existing on the shared disk.
As shown below, create the LOCK-DISK volume that will depend on a shared disk agent in a 1:1 relationship.
By using multiple shared disk agents, and one SCSI reservation agent, you can configure the dependency for use.
This disk with small capacity is allowed because it is used to check the node that can access the storage.
By setting the dependency between the SCSI reservation resource and the shared disk resource, you can prevent damages to DATA-DISK caused by Split-Brains and so on.

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[Figure] Shared disk and SCSI Lock resource is configured with different LUN( PrType=3)

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1. Shared disk and SCSI Lock resource is configured in same LUN (PrType=1).

[Figure] Shared disk and SCSI Lock resource configured in same LUN

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1. Install MCCS on both nodes
2. Set group
3. Add shared disk resource
4. Enable shared disk resource and check offline on both nodes
5. Add SCSI Lock resource (Select drive letter that created shared disk resource)
6. Enable SCSI Lock resource and check key in resource attribute of MCCS console.
7. Configure dependency of resources (SCSI Lock resource must go online first)
8. Test failover from node 2 to 1 
9. Test failover from node 1 to 2
10. Set application that customer uses

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[Figure] Shared disk and SCSI Lock resource configured with different LUN 

First, register shared disk agent according to the procedure and after check if it works normally, check disk of SCSI Lock agent.  

1. Install MCCS on both nodes
2. Set group
3. Add shared disk resource 
4. Enable shared disk resource and check offline on both nodes
5. Add SCSI Lock resource (Select new drive letter, not from the one in shared disk resource)
6. Enable SCSI Lock resource and check Key in resource attribute in MCCS Console
7. Change PrType 1 to 3 for attribute of SCSI Lock resource. (When SCSI Lock resource is added, make sure that SCSI Lock Disk Letter are disappeared from Windows Explorer of both servers.)
8. Configure dependency of resources (SCSI Lock resource must go online first)
9. Test failover from node2 to 1
10. Test failover from node1 to 2
11. Customer applications that use the volume setting

Adding

There are two way to add a resource which one is select this from a group name and another is select this from a resource type.

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Adding

Add the SCSI reservation application resource to a group.
Before configuring the SCSI reservation resource, you must configure the volume in advance by using the SCSI3 supporting storage. 

1. Select a group → right click → 'Add Resource'. 
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   [Figure] Adding Resource in a group
   
   
2. Select 'ServiceSCSILock' from Resource Type lists and click 'Next' button. 
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   [Figure] Select Resource Wizard View
   
3. Next steps are same as adding in resource type.

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1. 
   ResourceType → Right Click → Click Add Resource
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   [Figure] Adding Resource in a resource type
   Getting disk information.
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   [Figure] Screen of Getting disk information.
   
   
2. DriveLetter to be used for SCSILock can be selected.
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   [Figure] Selecting driver letter View
   When there is no disk for SCSI Lock resource, "Disk Not Found" message appears. 
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   [Figure] Disk Not Found
   Enter resource name. If you skip enter resource name, this will be given 'SLock_value' which value is selected driver letter.
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   [Figure] Selecting driver letter ViewSCSI Reservation Resource Added
   
   
3. Click the 'Finish' and SCSI Lock resource is added.
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   [Figure] Adding SCSI Lock resource is completed
   button to add the SCSI reservation resource. 
   You can immediately check the result in the management web console.
   
   

Deleting

Select resource type → right click → delete resource.

              Select "Delete Resource". 
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              [Figure] Delete SCSI Lock resource view

The deleted resource will immediately disappear from the management web console.

Status

The following table explains the status switching of the MCCS resource caused by a user's command and the status.
The command assumes that it is generated by a user.

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Attribute

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[Figure] SCSI Lock Resource Attribute view

SCSI Lock resource provides the following detailed attributes as well.
Setting are available in "Resource Unique Attribute" in resource's attribute tab.
Each attribute value has the following meanings:

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Attribute

Display the unique attribute of SCSI reservation resource.

scsicmd.cmd Command

Syntax

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Disk 0 (C:)'s PR is set to "No". So, you can see that the disk does not support SCSI3-PR.  (In general, the "C" drive is the system booting disk and it does not support SCSI.)
Besides, Disk 1 (D:)'s PR is set to "No". You can see that the disk does not support SCSI3-PR.(Internal Disk does not support SCSI3-PR.)
Disk 2 (E:) and Disk 4 (G:)'s SCSI3-PR is set to "Yes". So, it means that the storage used supports SCSI3- PR. Their Reserved-Key and Registered-Keys are set to "none". It means that they are not yet to be registered.
Disk 3 (F:)'s Reserved-Key and Registered-Keys at the source node are set to C29043F13* and C29043F13* and at the target node to C29043F13 and C29043F13. This means that a SCSI reservation agent was used to create the resource.
The (*) marked node with the Reserved-Key and Registered-Keys indicates that a disk is reserved. In addition, only the * marked node with the Reserved-Key value (ex: C29043F13*) can access the disk.