PowerPath and DMP issues

Thanks for the help. Can you email any documentation to



Appreciate the assistance.





On Thu, 01 Apr 2004 03:59:20 +0800, Lim Chee Hon
wrote:



gigastuff wrote:
On Wed, 31 Mar 2004 05:13:07 +0800, Lim Chee Hon
wrote:


Which CLARiiON you having now? If you say that you only have the
PowerPath Utility Kit, then I guess what you have is PowerPath base and
you are running CLARiiON CX200.


Actually, we are running a CX600.


When you install PowerPath, you need to configure the CLARiiON for it to
recognise your host and know which CommPath it should use. CommPath is
the path that CLARiiON use to communicate with PowerPath host for LUN
TresPass functionality. And do not forget about Navisphere Suite because
you need to specify you need the CLARiiON to do autotrespass or not.
These configuration depend on the OS you have.

fyi, the diffrent between PowerPath and PowerPath base is, PowerPath
base do not have load-balancing feature and only CX200 and below can run
PowerPath base.


To answer your question about the LUN assignment, it is not determine by
the CLARiiON, is by the person who configure it. Normally what will do
is balance the number of LUN that own by each SP. Unless you choose
"Auto Assign" while you creating LUN, then the LUN with odd LUN ID will
go to SPA and even go to SPB (or the other way, I can't recall). If the
LUN trespass (one path fail), then the LUN will go to the secondary
path/SP (means your PowerPath is working).


Sorry, but this does not really answer my question. I specifically
need to know what PORTS the LUN is assigned to, not what controller. I
know that you can explicity choose which controller to own the LUN (I
mentioned this in my original post). What I still am unclear is how to
tell the LUN to be exposed to a certain PORT. Do all ports on that
controller have access to the LUN? I am beginning to doubt that
because the server in question was only able to see the LUN after I
trespassed it to the other controller. This server has access to both
controllers but only 2 ports on each. I definitely understand the
concept of PowerPath but I need to know detailed information about the
PORTS.


Yes, all ports access to that LUN. Make sure each SP will access to both
SAN switch from diffrent SP port. I'm sorry that I do not know you have
another posting prior to this one.


Your question about Win2k, sorry for my poor english I'm not very sure
what are you asking but remember if you are having a CX200 or FC4500 or
FC5300, YOU CAN ONLY CONNECT PORT 0! DO NOT CONNECT 2 PORTS FROM 1 SP TO
THE FABRIC. Because port 1 is for direct attach 2 cluster nodes. If your
server cannot see the LUN, please check your switch zoning. Which HBA
you using? Do you install the correct driver and firmware? CLARiiON only
certify Emulex and QLogic for Win2k. If everything is fine, try run this
command:

powermt display # verify the path
powermt check # if it shows dead path, just remove them
powermt config
powermt display # see how many path you have now
powermt display dev=all # check the devices you have


Do you know if this same rule applies to a CX600? They have it
configured with 2 ports on each controller going to each switch.
In other words SPA P0, SPA P2, SPB P1, SPB P3 to one switch and
SPA P1, SPA P3, SPB P0, SPB P2 to the other.



Yes, this applies to CX600 and also to Symmetrix. But diffrent OS will
have diffrent set of commands to run. The example above applies to
Windows 2000.
Have you activate your PowerPath? Use powermt check_registration to find
out.
btw, can you verify those CommPath value is already properly configure?
go to Navisphere UI, right click on the array and select connectivity
status. You can also check is there any fibre log-in to all the SP ports
or not. If you got no fibre log-in to those ports, check your
connectivity or PowerPath.


From what you asking, the c#t#d#s#, I guess you are running solaris.


We are for some of the nodes.


Normally people don't disable PowerPath just for the sake of DMP. If you
are running PowerPath with the older version of VxVM, you just disable
DMP. But if you are having the new version of VxVM, you can't disable
DMP. There are some settings you need to do on both PowerPath and DMP.
Give me more detail of your environment and I will try to help you.

PowerPath will create its own pseudo device for fail-over purpose. But
if you want to integrate PowerPath and DMP you cannot create disk group
using PowerPath's pseudo device, and you can ONLY concatenate.



I was told to supress the mutliple paths to DMP, therefore leaving
only one exposed to Veritas. That leave PowerPath. The question still
remains, if I do this how will Veritas VM be aware of the LUN when a
controller failover happens. Does PowerPath present the same access
path when it fails-over to the other controller?


Have you add DGC as jbod into your VxVM xonfiguration?

run the command
# vxddladm listjbod

and you should see

VID PID Opcode Page Code Page Offset SNO length
===============================================
DGC ALL PIDs 18 131 8 16

If not you have to add it in by doing
# vxddladm addjbod vid=DGC pagecode=0x83 offset=8 length=16

If your connection if correct, run this command
# vxdmpadm getdmpnode enclosure=Disk

and you should see you have 4 paths to one device.

What is your email address? Let me send some documentation to you.
If you are not sure how your CLARiiON is configure in your environment,
you can always get a copy of CCPF from your reseller (this is a document
that MUST be generate by EMC engineer before they start doing
implementation, but since you have no direct access to EMC you can try
to ask your reseller to get it.)

you can email to me just remove the nospam from my email address.
If you really need something more detail, please give me your email
address and I will get back to you.

Lim, Chee-Hon

gigastuff wrote:


Hi all,

I am having some issues with a EMC Clariion unit and I was wondering
if it is related to PowerPath and DMP. Apparently our sole support is
through the VAR and not EMC so I cannot ask EMC directly.

Anyway, I need some clarification on how PowerPath works on a
low-level technical view. I think finally grasp the concept of what
the "basic" utility kit version of PowerPath is. Apparently this is
not for HBA fail-over but for making the host aware of a SP controller
failover (trespass). The basic version also apparently limits the
access to one port on each controller. That is all fine and well but I
need to know how the Flare OS assigns the LUNs to the controllers.

I know that you can choose the default owner when creating the LUN.
What I don't know is how Flare assigns the specific port on the
controller. In other words, how do I know if a LUN is accessible by
SPA port 0 as opposed to SPA port 1 when I first create it? Or does it
default to all the ports on the controller having access to the LUN?
The reason I have doubt about that is because one of the servers I
have connected to the SAN has access paths to both controllers.
However, when the LUN was owned by SPA, the server (Win2k) could not
see it in disk management. But, when I moved the LUN over to SPB it
could see it fine. This server only has access to 2 ports on each
controller. So, what I am assuming is that this server did not have
access to the port(s) on SPA that the LUN was residing. To sum this
up, how do you make sure the LUN is accessible by a specific port on
the controller when you are creating it? Does the '"basic,
utility-kit" version of PowerPath make this a moot point?

Okay, now the Veritas DMP questions. I was told by the Veritas rep
that I have to either suppress the multiple paths to DMP (leaving only
one open) or disable PowerPath. I understand that DMP views the LUN as
a metanode. That is how DMP can address it. So, if PowerPath were to
failover the LUN to a different controller, and thus a different
c#t#d#s#, how is Veritas Volume Manager aware of this? If I suppress
the multiple paths, wouldn't Volume Manager be unaware of the "new"
path created by PowerPath? Or does PowerPath consistently present the
LUN as the same c#t#d#s# when it fails over?

Also, is anyone running DMP and PowerPath at the same time? I have
read some whitepapers that stated they can now play nice with each
other but I still have my doubts.

Thanks.

ok, I will email to you.
Just to answer your question about "how to assign LUN to SP port". You
need Access Logix install on your CX600 and from there you can assign
LUN according to the server's HBA WWN. It is not actually assign the LUN
to the SP port but is to assign the LUN to which ever port that connect
yo your HBA, this is LUN masking.

You should check with your reseller why you only have PowerPath base
since you got a CX600. PowerPath utility kit is a must but you should
have a copy of PowerPath with a piece of license and license key on it.
Please check with the command powermt check_registration and if you do
not have any license key key-in during the installation, you can use
emcpreg -install to key in the license key.

gigastuff wrote:
Thanks for the help. Can you email any documentation to



Appreciate the assistance.





On Thu, 01 Apr 2004 03:59:20 +0800, Lim Chee Hon
wrote:



gigastuff wrote:

On Wed, 31 Mar 2004 05:13:07 +0800, Lim Chee Hon
wrote:



Which CLARiiON you having now? If you say that you only have the
PowerPath Utility Kit, then I guess what you have is PowerPath base and
you are running CLARiiON CX200.


Actually, we are running a CX600.



When you install PowerPath, you need to configure the CLARiiON for it to
recognise your host and know which CommPath it should use. CommPath is
the path that CLARiiON use to communicate with PowerPath host for LUN
TresPass functionality. And do not forget about Navisphere Suite because
you need to specify you need the CLARiiON to do autotrespass or not.
These configuration depend on the OS you have.

fyi, the diffrent between PowerPath and PowerPath base is, PowerPath
base do not have load-balancing feature and only CX200 and below can run
PowerPath base.


To answer your question about the LUN assignment, it is not determine by
the CLARiiON, is by the person who configure it. Normally what will do
is balance the number of LUN that own by each SP. Unless you choose
"Auto Assign" while you creating LUN, then the LUN with odd LUN ID will
go to SPA and even go to SPB (or the other way, I can't recall). If the
LUN trespass (one path fail), then the LUN will go to the secondary
path/SP (means your PowerPath is working).


Sorry, but this does not really answer my question. I specifically
need to know what PORTS the LUN is assigned to, not what controller. I
know that you can explicity choose which controller to own the LUN (I
mentioned this in my original post). What I still am unclear is how to
tell the LUN to be exposed to a certain PORT. Do all ports on that
controller have access to the LUN? I am beginning to doubt that
because the server in question was only able to see the LUN after I
trespassed it to the other controller. This server has access to both
controllers but only 2 ports on each. I definitely understand the
concept of PowerPath but I need to know detailed information about the
PORTS.


Yes, all ports access to that LUN. Make sure each SP will access to both
SAN switch from diffrent SP port. I'm sorry that I do not know you have
another posting prior to this one.


Your question about Win2k, sorry for my poor english I'm not very sure
what are you asking but remember if you are having a CX200 or FC4500 or
FC5300, YOU CAN ONLY CONNECT PORT 0! DO NOT CONNECT 2 PORTS FROM 1 SP TO
THE FABRIC. Because port 1 is for direct attach 2 cluster nodes. If your
server cannot see the LUN, please check your switch zoning. Which HBA
you using? Do you install the correct driver and firmware? CLARiiON only
certify Emulex and QLogic for Win2k. If everything is fine, try run this
command:

powermt display # verify the path
powermt check # if it shows dead path, just remove them
powermt config
powermt display # see how many path you have now
powermt display dev=all # check the devices you have


Do you know if this same rule applies to a CX600? They have it
configured with 2 ports on each controller going to each switch.
In other words SPA P0, SPA P2, SPB P1, SPB P3 to one switch and
SPA P1, SPA P3, SPB P0, SPB P2 to the other.



Yes, this applies to CX600 and also to Symmetrix. But diffrent OS will
have diffrent set of commands to run. The example above applies to
Windows 2000.
Have you activate your PowerPath? Use powermt check_registration to find
out.
btw, can you verify those CommPath value is already properly configure?
go to Navisphere UI, right click on the array and select connectivity
status. You can also check is there any fibre log-in to all the SP ports
or not. If you got no fibre log-in to those ports, check your
connectivity or PowerPath.


From what you asking, the c#t#d#s#, I guess you are running solaris.


We are for some of the nodes.



Normally people don't disable PowerPath just for the sake of DMP. If you
are running PowerPath with the older version of VxVM, you just disable
DMP. But if you are having the new version of VxVM, you can't disable
DMP. There are some settings you need to do on both PowerPath and DMP.
Give me more detail of your environment and I will try to help you.

PowerPath will create its own pseudo device for fail-over purpose. But
if you want to integrate PowerPath and DMP you cannot create disk group
using PowerPath's pseudo device, and you can ONLY concatenate.



I was told to supress the mutliple paths to DMP, therefore leaving
only one exposed to Veritas. That leave PowerPath. The question still
remains, if I do this how will Veritas VM be aware of the LUN when a
controller failover happens. Does PowerPath present the same access
path when it fails-over to the other controller?



Have you add DGC as jbod into your VxVM xonfiguration?

run the command
# vxddladm listjbod

and you should see

VID PID Opcode Page Code Page Offset SNO length
============================================== =
DGC ALL PIDs 18 131 8 16

If not you have to add it in by doing
# vxddladm addjbod vid=DGC pagecode=0x83 offset=8 length=16

If your connection if correct, run this command
# vxdmpadm getdmpnode enclosure=Disk

and you should see you have 4 paths to one device.

What is your email address? Let me send some documentation to you.
If you are not sure how your CLARiiON is configure in your environment,
you can always get a copy of CCPF from your reseller (this is a document
that MUST be generate by EMC engineer before they start doing
implementation, but since you have no direct access to EMC you can try
to ask your reseller to get it.)

you can email to me just remove the nospam from my email address.

If you really need something more detail, please give me your email
address and I will get back to you.

Lim, Chee-Hon

gigastuff wrote:



Hi all,

I am having some issues with a EMC Clariion unit and I was wondering
if it is related to PowerPath and DMP. Apparently our sole support is
through the VAR and not EMC so I cannot ask EMC directly.

Anyway, I need some clarification on how PowerPath works on a
low-level technical view. I think finally grasp the concept of what
the "basic" utility kit version of PowerPath is. Apparently this is
not for HBA fail-over but for making the host aware of a SP controller
failover (trespass). The basic version also apparently limits the
access to one port on each controller. That is all fine and well but I
need to know how the Flare OS assigns the LUNs to the controllers.

I know that you can choose the default owner when creating the LUN.
What I don't know is how Flare assigns the specific port on the
controller. In other words, how do I know if a LUN is accessible by
SPA port 0 as opposed to SPA port 1 when I first create it? Or does it
default to all the ports on the controller having access to the LUN?
The reason I have doubt about that is because one of the servers I
have connected to the SAN has access paths to both controllers.
However, when the LUN was owned by SPA, the server (Win2k) could not
see it in disk management. But, when I moved the LUN over to SPB it
could see it fine. This server only has access to 2 ports on each
controller. So, what I am assuming is that this server did not have
access to the port(s) on SPA that the LUN was residing. To sum this
up, how do you make sure the LUN is accessible by a specific port on
the controller when you are creating it? Does the '"basic,
utility-kit" version of PowerPath make this a moot point?

Okay, now the Veritas DMP questions. I was told by the Veritas rep
that I have to either suppress the multiple paths to DMP (leaving only
one open) or disable PowerPath. I understand that DMP views the LUN as
a metanode. That is how DMP can address it. So, if PowerPath were to
failover the LUN to a different controller, and thus a different
c#t#d#s#, how is Veritas Volume Manager aware of this? If I suppress
the multiple paths, wouldn't Volume Manager be unaware of the "new"
path created by PowerPath? Or does PowerPath consistently present the
LUN as the same c#t#d#s# when it fails over?

Also, is anyone running DMP and PowerPath at the same time? I have
read some whitepapers that stated they can now play nice with each
other but I still have my doubts.

Thanks.

You should check with your reseller why you only have PowerPath base
since you got a CX600. PowerPath utility kit is a must but you should
have a copy of PowerPath with a piece of license and license key on it.

As mentioned in gigastuffs posting from 03/24 (Clariion controller failover),
he inherit a system where hosts are only single attached to the fabric.
No need for full PowerPath license.

Rene