Only one ACP port per head; but connected to two different types of sas shelves...how to ACP?

[cahammitt]

Considering a FAS3240 HA pair with expanded I/O module only has one ACP port per head....how would one go about ACP connectivity when the system is connection to both a ds4243 and a ds2246 which are not allowed to co-mingle?

Is there a way to get additional ACP ports on a system?  Or must one choose to either ACP enable one type of stack [the 3Gb stack] or the other type of stack [the 6Gb stack]?  If that is indeed the case, consider this an RFE submission for additional ACP management ports....

This particular configuration is not discussed in any product documentation or public KB articles...but it should be!  I can see this as a common design.

ds4243's for dense sata drives; bulk data

ds2246's for fast sas drives; performance [I don't buy the using ds4243's with 3.5 inche 15krpm sas drives, the price / performance ratio just isn't there.]

I'd recommend a KB article on this...it is going to become a very common question...

I appreciate all comments...

sincerely,

A former NetApper...2005-2008

[ekashpureff]

Dear Former -

The shelves don't mingle due to the differences in SAS.

I don't think there's any problems with regard to ACP connections...

I hope this response has been helpful to you.

At your service,

Eugene E. Kashpureff

ekashp@kashpureff.org

Senior Systems Architect / NetApp Certified Instructor

http://www.linkedin.com/in/eugenekashpureff

(P.S. I appreciate points for helpful or correct answers.)

[cahammitt]

I understand they don't co-mingle...the question or the point is that I wish to have ACP connectivity on both the ds4243 stack and also on the ds2246 stack....the only way I see that as being possible is if one can configure another couple of ACP ports as there is only one per head which is great for one stack / one type of shelf...but that leaves me hanging for the other type of stack....I need two more ACP ports...

[ekashpureff]

I was trying to say that they DO co-mingle with regard to the ACP network (IP) whereas they DO NOT with regard to SAS loops...

I hope this response has been helpful to you.

At your service,

Eugene E. Kashpureff

ekashp@kashpureff.org

Senior Systems Architect / NetApp Certified Instructor

http://www.linkedin.com/in/eugenekashpureff

(P.S. I appreciate points for helpful or correct answers.)

[cahammitt]

Oh really!?  That would be interesting.  Perhaps you have a url to pass on to me?  I imagine if people think general ACP cabling connectivity is difficult...I imagine the config I am requesting is even more difficult.

Please forgive my ignorance; but I haven't found any docs on this and ACP is new to me, even if NetApp is not....

[cahammitt]

If you can truly combine the ACP network across different SAS Disk shelf types even though their data path cannot co-migle...that would mean that this is a DOC Burt [Documentation Bug; as the documentation is not clear and definitive]

Thanks for your comments Eugene.

[ekashpureff]

Err,

You're very welcome.

Don't think it's up to BURT level, but they could make the issue clearer in the docs.

I have to have guys label SAS and ACP interfaces for client installs - LOL ?

On the deeper dive -

I think even without ACP the different shelf loops will fall back to using the data path for control messages if there is no ACP installed.

I hope this response has been helpful to you.

At your service,

Eugene E. Kashpureff

ekashp@kashpureff.org

Senior Systems Architect / NetApp Certified Instructor

http://www.linkedin.com/in/eugenekashpureff

(P.S. I appreciate points for helpful or correct answers.)

[vmsjaak13]

From TR-3838 "Storage Subsystem Configuration Guide"

"The addition of Alternate Control Path (ACP) functionality, which removes management traffic from the data path, further increases the efficiency of the data path bandwidth in SAS stacks."

and...

"The current implementation of ACP supports the reset and power cycle of SAS expanders. Only a single Ethernet port is required per controller, regardless of the number of stacks present in the storage configuration. NetApp highly recommends dedicating a single Ethernet port per controller to enable ACP in order to increase system resiliency."

As ACP only does management, I don't think it matters if you have a mixed shelf landscape.

I agree with Eugene, that NetApp could be clearer on this.

Regards,

Niek Baakman