topic Re: SecurePath for EVA3000 in Disk Enclosures

SecurePath for EVA3000

Hoang Minh Tuan — Fri, 14 Jan 2005 05:28:32 GMT

Hi All,

I don't know much about SecurePath. I've just configurated SecurePath for server rp3440 and EVA3000 and set load balancing function.
When I use command #spmgr display to display how it work, I realize it load balancing on F/C link from server (2 ports) to SAN switch and on only one Controller with 2 F/C port.
Can SecurePath do load balancing between 2 Controllers, it mean that all 2 Controllers is simultaneously active. If it have, how I should do?
Thanks in advanced

HMT

Re: SecurePath for EVA3000

Rainer von Bongartz — Fri, 14 Jan 2005 05:43:40 GMT

The EVA controllers are not active-active.
You always have one active and one passive controllers, so no load balancing is possible.

This feature is implememted in the XP and VA disk arrays, but not in COMPAQ'S EVA's.

That's one of the reasons I personally do not count an EVA as an alternative for the VA.

Regards
Rainer

Re: SecurePath for EVA3000

Uwe Zessin — Fri, 14 Jan 2005 06:58:03 GMT

Sorry, but that is not correct - you are trying to transfer your definition of active/active into a different world.

The EVA controllers are Active/Active, because you can divide different virtual disks over both controllers and they will both serve I/Os. What is true is that you can't do I/O to a single virtual disk through both controllers, because only one controller manages a virtual disk at a time.

The VA works a bit different. A single controller is responsible for an entire redundancy group with all LUNs it holds. If you attempt to do I/O through the other controller, he will re-route the request through the internal bus so the controller owning the RG does the disk I/O.

See the discussion of "Performance Path" on page 45 in the User and Service Guide (A6183-96007, March 2004).

Re: SecurePath for EVA3000

Nguyen Anh Tien — Sat, 15 Jan 2005 00:24:49 GMT

Hi Tuan.
Secure Path can not do load balancing between 2 Controllers. EVA3000 allow to config One controller per VDISK (LUN) and fail over to other controller. secure path not support for "fail back mode" of controller.
Secure path support load balancing on Fabric only (From HBAs <-> Fabric<-> one controller ).
That all.
tienna

Re: SecurePath for EVA3000

Hoang Minh Tuan — Sun, 16 Jan 2005 23:22:47 GMT

Thanks all,

All of your information make my attitude more clearly.
To Tien: SP not only can set fail over, but also can be a fail back mode (I'm sure?)