SecurePath or pvlinks

[Leif Halvarsson_2]

Hi,
I have found some notices here about that pvlinks is not supported for EVA3000/5000 (but, seems to be supported for EVA4000/6000/8000). But, I can't find any references to the EVA dokumentation.

Is there anyone who know ?

- Does pvlink not work at all, or is it just not supported ?

- Does anyone know why ?

[Luk Vandenbussche]

Hi Leif,

I am 100 % sure that pvlinks doesn't work on EVA3000 and EVA5000, you need securepath for hpux here.

In the new controllers in EVA4/6/8000 pvlinks are working

[Slawomir Gora · Accepted solution]

Hi,

for EVA3k and EVA5k pvlinks are not supported
and you can't use it because controllers are working in active/passive mode for
LUN. LUN is visible only by one controller and you need SecurePath software
to switch to alternate controller (for linux Qlogic driver has failover mechanism build-in).

EVA4k/6k/8k has active/active controllers and
there is no need to use SecurePath but you can work with PVLinks look at:
"Operating Systems, Cluster and High Availability Compatibility"


http://h18006.www1.hp.com/products/quickspecs/12234_div/12234_div.html

[Leif Halvarsson_2]

Hi,

Is it an general problem , pvlink usage need active/active controller and will not work for any active/passive.

Or, is the problem specific for EVA 3000/5000.

[Vincent Fleming]

No PVLinks does not work with EVA3000/5000 - as mentioned above, the LUNs appear on one controller only. If a path failover is required (controller goes away or something), the host software (SecurePath) tells the remaining controller to take over the LUNs. So, the controller failover is not built into the array itself, but into the SecurePath.

With the EVA4000/6000/8000, both of the controllers present all LUNs, and controller failover is automatic, so you don't need SecurePath...

PVLinks doesn't know about controllers as such, so it won't work with EVA3000/5000. It will work just fine with the EVA4000/6000/8000.

Regards,

Vince

[Vincent Fleming]

We crossed postings...

It's a "problem" specific to the EVA3000/5000, because the redundant controller doesn't present the LUN(s) to the host, where the new EVAs do present the LUN(s).

Regards,

Vince

[Leif Halvarsson_2]

Hi,

Thanks Vincent, it makes things a little more clear to me. Just some additional questions.

"the redundant controller doesn't present the LUN(s) to the host"

Do you have any more details ?

Obviously the host see "something", there is a devicefile created for every path to the LUN (4 devicefiles) if no Secure Path is installed.

Is the problem related to the active/passive concept itself (and apply to all such disk arrays) or, is it specific for the EVA3000/5000 only (and, other arrays with active/passive controller may work).

[Uwe Zessin]

Your observation is correct, Leif.

> "the redundant controller doesn't present the LUN(s) to the host"

That claim is simply incorrect! The EVA3000/5000 *does* present a virtual disk on all 4 controller ports.

However, as has been explained already, a virtual disk is managed by one controller and you can only do host I/O through this controller on the EVA3000/5000. The other controller *must* present the virtual disk, too - otherwise the multipath software (e.g. Secure Path) would not know that there are any 'standby path'. What the other controller does is, it responds to LUN inquires with a 'NOT READY' response.

On the EVA 4000/6000/8000 a virtual disk is still managed by one controller, but the other controller operates as a proxy and will send I/O requests to the managing controller (similar to what the VA7xxx does).

[F.Monette]

Hello,

Since December 2005, the new version of VCS code 4.001 on EVA3000/5000 are now working Active-active like EVA4K/6K/8K. So, PVLINKS are supported with VCS 4.001

FM

[John Payne_2]

Leif,

Your origional question "Does anyone know why?":

The EVA/SecurePAth, etc came from the Compaq side of the house. Support for HPUX came at the same time the meger happened. It took a while for that team to integrate into the HPUX way of thinking. They are getting there.

Just my $0.02 (American)
John