We had outage couple of days ago and our cluster disk went offline. When analyzing the logs with Microsoft, they said we need to diasble Persistent Reservation flag.
Microsoft comments “This mostly happens due to a persistent reservation present on the disks which does not allow the clusdisk.sys to perform I/O operation on the cluster disks and blocks it. This also prevents failover to other nodes.
Action Plan:
Engage the Storage vendor and ask them to remove the persistent reservations on the cluster disks.”
Microsoft keep saying to engage Storage vendor and storage vendor saying is done from host.
Thanks for the reply. SCSI-3 presistent reserver is enabled on the FA adapters. you mean to say that it should be disabled from the SAN end by using the command given.
Thanks for reply. We keep saying to SAN team and they say its enabled for all servers, if you don't need it then you need to disable from host. Is this something possible?
Also can we disabled SCSI-3 Persitent Reserver just for Lun's ?
By the way this Server has Multipath enabled, i read some where that SCSI3 - PR needs to be enabled for Multipath to work? is that so or its safe to disable as this is Windows 2003?
they must be thinking about this parameter which is set at the FA level, it has nothing to do with persistent reservation, that one needs to stay at whatever value it's currently set (most likely enabled)
SCSI_3(SC3)
: Enabled
you want to disable SCSI-3 Persitent reservation just for the LUNs presented to that specific cluster. I have windows 2003 clusters without SCSI3-PR enabled and PowerPath is working just fine, i have never seen that requirement.
I have a meeting with SAN team later today, hopefully i can show them this. By the way Microsoft Keep saying Persistent Reseravtion flag, and they are not sure if its is called SCSI3- PR, is there really a difference or both terms are the same.
"What Symmetrix director flags (bits) are required for Microsoft Windows Server 2003 and 2008?"
ID:
emc200609
Usage:
856
Date Created:
10/28/2008
Last Modified:
02/23/2012
STATUS:
Approved
Audience:
Customer
Knowledgebase Solution
Question:
What Symmetrix director flags (bits) are required for Microsoft Windows Server 2003 and 2008?
Question:
What are the Symmetrix director bit flags for Windows?
Environment:
Product: Symmetrix
Environment:
OS: Microsoft Windows Server 2008
Environment:
OS: Microsoft Windows Server 2003
Fix:
The following FA director flag settings need to be configured to support Windows Server 2003 and 2008
Common Serial Number (C)
Host SCSI Compliance 2007 (OS2007)
SCSI-3 SPC-2 Compliance (SPC2)
SCSI-3 compliance (SC3)
For FC Switch Base Topology (FC−SW), Enable Auto Negotiation (EAN), Point−to−Point (PP) , Unique WWN (UWN).
For FC Loop Base Topology (FC−AL), Enable Auto Negotiation (EAN), Unique World Wide Name (UWN)
Additionally for Windows 2008 Failover Cluster, the Persistent Reservation attribute SCSI3_persist_reserv must be enabled on each Symmetrix DMX device used. This should NOT be done to devices for Windows 2003 clusters. EMC recommends that the SCSI3_persist_reserv attribute be only set on devices that require it.
For detailed information on changing these settings please refer to the Solutions Enabler Symmetrix Device Masking CLI Product Guide, Solutions Enabler Symmetrix Configuration Change CLI Product Guide and Solutions Enabler Symmetrix Array Controls CLI Product Guide available on Powerlink. Some SYMCLI examples are provided below.
No specific bit is required for iSCSI environment, with the following exception: VCM bit is required to enable the iSCSI initiator access login and, optionally, the iSCSI Challenge Handshake Authentication Protocol (CHAP) security configuration.
Notes:
If the OS2007, SPC2, SC3 FA flags are set at either the FA level or the initiator level and/or the PER flag is set at the device level then the hosts affected by these changes MUST be rebooted as the SCSI protocols in use will have changed at the FA level and the HBA needs to reinitialize communication with the FA.
Notes:
Director flags can be set globally for each director, and the below example will show this configuration information. See "Setting Port Characteristics" in the Solutions Enabler Symmetrix Array Controls CLI Product Guide and Solutions Enabler Symmetrix Configuration Change CLI Product Guide for detailed information on changing the SCSI protocol Port Flags and the Fibre Protocol Port Flags.
Please note, making changes globally for each director will affect all hosts connected to that port. In most instances where there are multiple types of hosts (Linux, Windows, Solaris) it may be a better option to set it per initiator.
To see the current director flag settings, run the following Solutions Enabler command:
symcfg list -sid xxxx -v -dir all
You can also set any of the director flags per host initiator. See "Setting the HBA port flags" in the Solutions Enabler Symmetrix Array Controls CLI Product Guide or see "Setting the Heterogeneous Host Configuration" in the Solutions Enabler Symmetrix Device Masking CLI Product Guide for detailed information. If the Symmetrix is running an Enginuity version earlier than 5671.68.71, 5771.104.114, or 5772.55.51 the OS2007 flag can only be enabled via a CE or symconfigure bin file change. Refer to solution emc183161 for details.
To display what director flags have been set per host initiator, run the following Solutions Enabler command.
symmaskdb -sid XXXX list database -v (without the -v you will not see the flags)
To enable the necessary director flags for an initiator on director 4a port 0 using symmask:
symmask -sid xxxx -wwn xxxxxxxxxxxxx -dir 4a -p 0 set hba_flags on C,OS2007,SC3,SPC2 -enable
symmask refresh (this command is required after performing the above command)
To enable the necessary director flags for an initiator group using Symaccess:
symaccess -sid xxxx -type init -name myig1 set ig_flags on C,OS2007,SC3,SPC2 -enable
To display the flags from the previous command using symmaccess:
symaccess -sid xxxx -type init show myig1 -detail
To enable the SC3, SPC2 & OS2007 flags globally on the FA 1D port 0 via symconfigure, create a text file similar to below..
set port 1d:0 SCSI_3=enable, SPC2_Protocol_Version=enable, SCSI_Support1=enable;
Notes:
To show whether the Persistent Reservation attribute has been set on a Symmetrix device for Failover Cluster, run the following command:
symdev show XXXX -sid XXXX
Look for the setting "SCSI-3 Persistent Reserve" - it should be enabled. If it is not enabled, you will need to run the following symconfigure command to enable it:
Needed a help. We have provisioned LUNs from DMX4-24 5773 to one of the Sun Solaris Server (10.5). But the LUNs are not visible at host end. Do we need to enable any Flag for this. If yes, please guide with commands.
dynamox
11 Legend
•
20419 Posts
•
87439 Points
2369
0
Posted September 24th, 2012 14:00
what array ?