topic Re: HP Smart Array 6404 controller query in Disk Enclosures

HP Smart Array 6404 controller query

ITeam — Wed, 02 Nov 2005 12:30:42 GMT

Hi. I have the above controller in an Integrity RX2620 which is currently configured with a logical disk (RAID 1+0) comprising of 2 physical disks. They are currently sitting on channel 1, id 0 & channel 1, id 1. This is confirmed by doing: saconfig /dev/ciss4.

There is, though, also a device file: /dev/ciss5 for the other 'half' of the controller which is doing nothing at present. I would like to know if it is possible to change the logical disk to span both halves (for extra resilience)? The instructions for the set up of the controller do not make this clear.

Many thanks.

Re: HP Smart Array 6404 controller query

Steven E. Protter — Wed, 02 Nov 2005 12:52:21 GMT

If the controller supports it the OS would. It's called alternate pathes or PVLINKS and it provides two pathes or more to one physical disk.

Creates redundancy.

Disk shows up on ioscan and works?

Probably alternate path will too.

SEP

Re: HP Smart Array 6404 controller query

Torsten. — Wed, 02 Nov 2005 13:20:25 GMT

AFAIK, the 2 disks at the bottom are on the same channel. You can connect the top disk to the other channel.

See this document for additional info:

http://docs.hp.com/en/5971-4280_2nd_ed/5971-4280-2nd-ed.pdf

Re: HP Smart Array 6404 controller query

Uwe Zessin — Wed, 02 Nov 2005 13:47:23 GMT

The SA6404 is really made from two SmartArray controllers. Not sure if I understand your question correctly, but a single module does not have access to all 4 SCSI channels, so a disk drive array can only span over 2 channels.

For extra resilience you might want to create a host-based mirror of logical disks, but what do you do if the SA6404's base module fails? That means you have lost access to the expander, too.

Re: HP Smart Array 6404 controller query

ITeam — Thu, 03 Nov 2005 05:14:44 GMT

I have just noticed in the SA config instructions that the 6404 controller does not support configuring devices across the two controllers - I think this answers my question.