Access Zone Failover with DFS single Path Referral


DFS Single Folder Target Failover with Eyeglass Access Zone Failover




Summary Objective:

Some customers have many DFS links with only a single smartconnect DFS target.  It is possible to fail this over using access zone failover with Eyeglass.  This would only be done in time sensitive scenario where updating DFS referrals and using Eyeglass DFS mode is not possible.


The Results

The testing showed that post access zone failover with open files or without any open files.  The DFS mount failed to survive the smartconnect zone failover, requiring the client to unmount and remount the DFS folder.


The Eyeglass DFS mode with dual path referral paths is recommended in all cases for seamless failover but access zone failover with single referral path will behave the same as none DFS mounted shares.


Test Objective:

To observe the behaviour of DFS client (with and without Open Files) upon Eyeglass Access Zone Failover for the DFS mounted folder with a single DFS Folder Target.


Setup:

DFS

DFS Namespace with only a single Folder Target as the referral. Configured the primary cluster as the referral folder target.


Eyeglass

Eyeglass version 1.6.3

Configure the Eyeglass as per DFS Mode Failover Guide (http://documentation.superna.net/eyeglass-isilon-edition/configure/eyeglass-microsoft-dfs-geographic-share-failover-and-failback), with the following change:

  • Create a normal igls-hint for the dedicated IP Pool for DFS instead of igls-ignore hint. With this setting, we can see the Network Mapping like the following figure.





DFS Test Folder

2 DFS Folders are used for this test:

  • DFS folder #1 for Open File test

  • DFS folder #2 for  no Open File test


Test Plan:

  1. Create 2 SyncIQ Policy to replicate DFS folder#1 and DFS folder#2 from primary cluster to secondary cluster

  2. Configure the igls-hint as per this setup section (use normal igls-hint instead of igls-ignore for the dedicated IP pool for DFS)

  3. Enable DFS mode for both SyncIQ Policies

  4. Prepare test files on DFS folder#1 and DFS folder#2.

  5. Keep the test file on DFS folder#1 open. Keep updating the file during the failover process

  6. Execute the Eyeglass Access Zone Failover - this will also perform failover on both DFS related SyncIQ policies

  7. Verify the DFS folders access during the failover process (for the case of the Open File) and after the Failover has completed (for both with and without Open File)



Test Result:

  1. Eyeglass Access Zone Failover has completed successfully - no error

  2. SmartConnect Access zone for the primary cluster is failed over to the secondary cluster

  3. Open File Test: during failover process, the updates were not saved to the file. Error message: Lost connection.

  1. After failover has completed, both DFS folders are not accessible.


  1. DFSutil display the following status:



C:\>dfsutil  diag viewdfspath \\ad1.test\t1492\z02-smb01


Destination Path <\\ad1.test\t1492\z02-smb01> is inaccessible

Could not execute the command successfully

SYSTEM ERROR - The network name cannot be found.



C:\>dfsutil  diag viewdfspath \\ad1.test\t1492\z02-smb02


Destination Path <\\ad1.test\t1492\z02-smb02> is inaccessible

Could not execute the command successfully

SYSTEM ERROR - The network name cannot be found.



C:\>dfsutil cache referral

5 entries...

Entry: \AD1\t1492\z02-smb01

ShortEntry: \AD1\t1492\z02-smb01

Expires in 1271 seconds

UseCount: 1 Type:0x1 ( DFS )

  0:[\cluster07-z02.ad1.test\z02-smb01] AccessStatus: 0xc00000cc ( ACTIVE TARGE

TSET )


Entry: \AD1\t1492\z02-smb02

ShortEntry: \AD1\t1492\z02-smb02

Expires in 1290 seconds

UseCount: 1 Type:0x1 ( DFS )

  0:[\cluster07-z02.ad1.test\z02-smb02] AccessStatus: 0xc00000cc ( ACTIVE TARGE

TSET )


Entry: \AD1\t1492

ShortEntry: \AD1\t1492

Expires in 0 seconds

UseCount: 0 Type:0x81 ( REFERRAL_SVC DFS )

  0:[\AD1\t1492] AccessStatus: 0 ( ACTIVE TARGETSET )


Entry: \AD1.test\sysvol

ShortEntry: \AD1.test\sysvol

Expires in 645 seconds

UseCount: 0 Type:0x1 ( DFS )

  0:[\ad1.AD1.test\sysvol] AccessStatus: 0 ( ACTIVE TARGETSET )


Entry: \ad1.test\t1492

ShortEntry: \ad1.test\t1492

Expires in 262 seconds

UseCount: 0 Type:0x81 ( REFERRAL_SVC DFS )

  0:[\AD1\t1492] AccessStatus: 0 ( ACTIVE TARGETSET )



DfsUtil command completed successfully.





  1. The DFS folder access can only be resumed by disconnecting and reconnecting the network mapped drive.