Preventing LUN rebalance by the MPP (RDAC) driver on Linux hosts

Asset ID:	1-71-1005465.1
Update Date:	2010-07-15
Keywords:

Solution Type Technical Instruction Sure

Solution 1005465.1 : Preventing LUN rebalance by the MPP (RDAC) driver on Linux hosts

Related Items


Sun Storage 6540 Array
 Sun Storage 6130 Array
 Sun Storage 6140 Array

Related Categories


GCS>Sun Microsystems>Storage - Disk>Modular Disk - 6xxx Arrays

PreviouslyPublishedAs
207588

Description
The RDAC Multi-Path Proxy (MPP) driver for Linux is a multipathing driver designed to operate with the following arrays:
Sun StorEdge[TM] 6130 Array
Sun StorageTek[TM] 6140 Array
Sun StorageTek[TM] 6540 Array

Steps to Follow
The /etc/mpp.conf file contains configurable parameters for the MPP 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 :

edit the file /etc/mpp.conf
set DisableLunRebalance=3
save and exit the file
run 'mppUpdate' to create new initrd image
reboot the system to activate the new setting

Product
Sun StorageTek 6540 Array
Sun StorageTek 6140 Array
Sun StorageTek 6130 Array (SATA)
Sun StorageTek 6130 Array

MPP, RDAC, linux, multipathing, driver, multipath, redhat, suse, 6130, 6140, 6540, lun, failover, failback, DisableLUNRebalance
Previously Published As
88070

Change History
Date: 2006-12-18
User Name: 95826
Action: Approved
Comment: - verified metadata
- review date ok : 2007-12-15
- checked for TM - none added
- checked audience : contract
Publishing
Version: 3

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