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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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  Small disk capacity of about 1GB is available. But the content is not protected.

Configuration

SCSI-Lock resource can be configured in 2 ways with shared disk resource. Configuration process changes according to the attribute value of SCSI Lock resource.

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1. When shared disk and SCSI Lock resource is configured with the same LUN (PrType=1)When you define an attribute of SCSI Lock resource as PrType=1, you can configure shared disk and SCSI Lock resource with the same LUN.LUN 

SCSI Lock agent manages DATA-DISK(shared disk resource) using by MOUNT/UMOUNT command and manages LOCK-DISK(SCSI Lock resource) using by SCSI-3 PR as shown below.
By setting up the dependency between SCSI Lock resources and shared disk resources, any damage of data-disk can be prevented which may occur in such case like Split-Brain.

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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)

At this type, shared disk agent manages DATA-DISK where user data is stored and SCSI lock agent uses exclusive LUN for key reservation. Therefore, two LUNs is required at least.
Lock-disk volume is created for 1:1 dependency with shared disk agent like a figure below.
By using multiple shared disk agents, and one SCSI reservation agent, you can configure the dependency relationship for use.
The storage capacity of this disk can be small 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. 

Image Removed   

[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 device path that created shared disk resource)
6. Enable SCSI Lock resource and check key in resource attribute of MCCS web 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
    

2.Shared disk and SCSI Lock resource configured with different LUN (PrType = 3)

Image Removed

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

Registration Procedures 

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 device path which is not assigned for 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
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 2Customer applications that use the volume setting
    

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. When add a resource from a group name, select a group → right click → 'Add Resource'. 
   
   
2. Select 'SCSILOCK' from Resource Type lists and click 'Next' button. 
   
   
3.  If you select a device path used for the SCSI reservation resource, a name will be automatically recommended.
   
   [Figure] SCSI Reservation Resource Added
   
   
4. Click the 'Finish' 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.
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

Display the unique attribute of SCSI reservation resource. 

scsicmd Command

Syntax

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