topic second controller in VA7100 in MSA Storage

second controller in VA7100

CA926134 — Mon, 24 Feb 2003 19:52:01 GMT

Hi there,

I just added a second controller to my VA7100. My Win2K servers that connected to the VA are now showing duplicate drives. They are showing the original drive letter and a new one.

Is this normal?

Thanks in advance.

Guy

Re: second controller in VA7100

CA650643 — Mon, 24 Feb 2003 22:03:30 GMT

Guy,

Yes and no.

The second controller is intended for redundant access - you're supposed to have 2 FC cards in each server, and path failover software (ie: AutoPath).

AutoPath makes the 2 "disks" look like only 1, and manages the multiple links between the server and storage.

So, what you are seeing is normal for a host connected to both controllers of a VA and lacking AutoPath.

Meanwhile, a suggestion - DO NOT EVEN ATTEMPT to access those "extra" drives - you can overwrite your data!

Good luck,

Vince

Re: second controller in VA7100

Eugeny Brychkov — Tue, 25 Feb 2003 11:05:23 GMT

Vince is correct. I only wish to add that in this configuration you built Autopath software is a must
Eugeny

Re: second controller in VA7100

CA926134 — Tue, 15 Apr 2003 11:29:32 GMT

Each of my servers have only 1 HBA, and my two controllers are connected to my Brocade switch. I currently have four servers on the switch. two are showing redundant drives, two are not. Three of the HBA are same make and model, Qlogic QLA2200F.

Will Autopath make any difference? Do I have an incorrect configuration?

Thanks in advance.

Guy

Re: second controller in VA7100

Eugeny Brychkov — Tue, 15 Apr 2003 11:46:42 GMT

I would say not 'incorrect' config, but 'unsupported'.
As soon as you have one switch and connected both VA controllers to this switch then with one HBA in the server it will see LUNs twice, with two HBAs - 4 times.
In case it sees only one time in this config I suspect your switch has zoning configured.
It is not dependant on how many HBAs server has installed - if server sees LUNs more than one time, Autopath have to be installed (OS does not support redundant paths by itself).
If you configured zoning and server sees LUNs only one time - do not install autopath
Eugeny

Re: second controller in VA7100

Eugeny Brychkov — Tue, 15 Apr 2003 12:03:24 GMT

Yes, about difference. Autopath driver discovers all devices with redundant paths and represents only one device to the OS. If path to the device will fail, then Autopath driver will automatically switch to next available hardware path device accessible through but from OS view nothing will change. So there're 2 benefits (at least):
1. system sees only one device instead of multiple ones (thus not trying to corrupt data writing different signatures to the same LUN);
2. system does not care about paths, failures etc - it simply accesses device through Autopath driver
Eugeny