topic Re: EVA controller interconnect cable question in Disk Enclosures

EVA controller interconnect cable question

lc6606 — Fri, 05 Jun 2009 05:34:23 GMT

I have 2 questions;

1. What type of information flows thru the controller interconnect cable and MP port?

2. What happen if the controller interconnect cable is broken; can both controller still function like normal?

Re: EVA controller interconnect cable question

Jozef_Novak — Fri, 05 Jun 2009 05:56:17 GMT

Hello,

which EVA model do you have ? The controller interconnect cable (in case of EVAs other than the 4400) is used for data like cache mirroring, synchronization, passing through read requests issued to non-owning controller etc. I haven't experienced an interconnect failure so far but I assume that it represents a serious condition as the above mentioned information is not passed between the controllers. However I am not able to say how the storage system reacts in that case.

J.

Re: EVA controller interconnect cable question

lc6606 — Fri, 05 Jun 2009 06:00:09 GMT

Hi J,

I have a eva4400.

Do u have any docs explaining the function of controller interconnect cable?

LC

Re: EVA controller interconnect cable question

Jozef_Novak — Fri, 05 Jun 2009 07:14:14 GMT

Hello (again),

EVA4400 is the only model that does not have an interconnect cable. The controller chassis is 2U in size, housing both controllers and the entire inter-controller communication goes through the chassis backplane.

J.

Re: EVA controller interconnect cable question

Uwe Zessin — Fri, 05 Jun 2009 08:34:02 GMT

The interconnect cable was meant to enable a 'cross-kill'. One controller could force-reboot the other one. It wasn't functional at least on introduction.

The MP (Mirror-Port) is used for controller to controller communication, data transfers to the mirror cache and proxied reads.
The first generation EVA had one MP, but could fail over to one of the DP ports.

Re: EVA controller interconnect cable question

lc6606 — Wed, 10 Jun 2009 08:37:48 GMT

Hi all,

Thanks for the comments; it is all cleared now.