Sun Storage 6180 Array
 
Sun Storage 6580 Array
 
Sun Storage Flexline 280 Array
 
Sun Storage 6780 Array
 
Sun Storage 2510 Array
 
Sun Storage 2540 Array
 
Sun Storage 2540-M2 Array
 
Sun Storage 6140 Array
 
Sun Storage 2530 Array
 
Sun Storage 2530-M2 Array
 
Sun Storage Flexline 380 Array
 
Sun Storage 6540 Array
 
Sun Storage 6130 Array
 
Sun Storage Flexline 240 Array
 

PLA-Support>Sun Systems>DISK>Arrays>SN-DK: 6140_6180
 
_Old GCS Categories>Sun Microsystems>Storage - Disk>Modular Disk - 6xxx Arrays
 

Applies to:

Goal

 How to preventing LUN rebalance by the MPP (RDAC) driver on Linux hosts

Fix

The RDAC Multi-Path Proxy (MPP) driver for Linux is a multipathing driver designed to operate with the Sun StorageTek[TM] 2500, Sun Storage[TM] 6000 and Flexline arrays.

The /etc/mpp.conf file contains configurable parameters for the MPP/RDAC driver.

EXAMPLE CONTENTS :

 VirtualDiskProductId=StorageArray
 DebugLevel=0x0
 NotReadyWaitTime=270
 BusyWaitTime=270
 QuiescenceWaitTime=270
 InquiryWaitTime=60
 MaxLunsPerArray=256
 MaxPathsPerController=4
 ScanInterval=60
 InquiryInterval=1
 MaxArrayModules=30
 ErrorLevel=3
 SelectionTimeoutRetryCount=0
 UaRetryCount=10
 RetryCount=10
 SynchTimeout=60
 FailOverQuiescenceTime=20
 FailoverTimeout=120
 FailBackToCurrentAllowed=1
 DoUaRetry=1
 ControllerIoWaitTime=300
 ArrayIoWaitTime=600
 DisableLUNRebalance=0
 ArrayFailoverWaitTime=300

Descriptions of these parameters, valid settings and meaning of those settings are all documented in the "RDAC" man page.

The description for the "DisableLUNRebalance" parameter is :

Controls the failback scan task behavior of rebalancing the LUNs or putting the LUNs back on their preferred owning controller, when failed paths are determined to be good and usable again. 

This parameter can take on values from 0-3.
0 - means Lun rebalance is enabled for both AVT and non-AVT modes (default)
1 - means Lun rebalance is disabled for AVT mode and enabled for non-AVT mode
2 - means Lun rebalance is enabled for AVT mode and disabled for non-AVT mode
3 - means Lun rebalance is disabled for both AVT and non-AVT modes

So, to prevent Linux hosts from rebalancing LUNs automatically to their preferred controller, change the setting of the "DisableLUNRebalance" variable from 0 to 3.

The full procedure to do this is :

1. Edit the file /etc/mpp.conf
2. Set DisableLunRebalance=3
3. Save and exit the file
4. Run 'mppUpdate' to create new initrd image
5. Reboot the system to activate the new setting

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