Celerra iSCSI Targets visible to all Initiators

Posted: September 21, 2009 in Celerra, Tips and Tricks, VMware

Something I noticed last week while working on a customers site was multiple iSCSI initiators logged into iSCSI targets which I had not granted access.

I’ll fire up my lab to demonstrate what I saw and how to change the behavior.

Here on my Celerra simulator I have three iSCSI Targets configured for VMware, Exchange and SQL. Each Target uses a different interface with its own IP address.

targets

Im going to use my Exchange Virtual Machine to demonstrate, but before I flick to the VM, I want to show the mask for the VMware and SQL iSCSI targets.

VMware –Only the vSphere initiator masked here.

vmware_target

SQL – Only the SQL initiator masked here.

sql_target

Now lets flick to the properties of the Microsoft iSCSI initiator in my Exchange VM. You can see Ive only configured the IP address assigned to the Exchange iSCSI target.

discovery

Now lets take a look to see what targets are visible.

iscsi initiator

And here you can see the iSCSI initiator is able to see all three targets. The reason for this is because by default the Celerra returns information on all targets to all initiators regardless of the lun mask.

Although the systems can only access the luns the mask permits, it’s still quite messy when you have 5, 10, 15 targets on the Celerra which are visible to all Microsoft initiators. So luckily the guys who write the code have a parameter for us to change which alters the default behavior.

First lets confirm the current setting.

[nasadmin@csprod ~]$ server_param server_2 -f iscsi -i SendTargetsMode
server_2 :
name                    = SendTargetsMode
facility_name           = iscsi
default_value           = 0
current_value           = 0
configured_value        =
user_action             = none
change_effective        = immediate
range                   = (0,1)
description             = Enables return of information about inaccessible targets

Now lets change the current value to 1

[nasadmin@csprod ~]$ server_param server_2 -facility iscsi -modify SendTargetsMode -value 1
server_2 : done

And now confirm the current vaule = 1

[nasadmin@csprod ~]$server_param server_2 -f iscsi -i SendTargetsMode
server_2 :
name                    = SendTargetsMode
facility_name           = iscsi
default_value           = 0
current_value           = 1
configured_value        = 1
user_action             = none
change_effective        = immediate
range                   = (0,1)
description             = Enables return of information about inaccessible targets

So what Ive  done here is configured the Celerra to only return information on iSCSI targets when luns have been masked to the client initiator.

Restarting the iSCSI service on the Celerra causes the initiators to drop the targets to which it has no luns maksed (Actually do this with caution as it causes all iSCSI connections to drop)

Lets take a look at  my Exchange VM after this has been done.

1target

Much Better ! If you dont use the Microsoft iSCSI initiator than this is not really going to bother you, VMware’s software initiator only shows targets when connected to luns.

In my honest opinion this should be the default setting.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s