topic Re: Read mirror-disk with normal SCSI controller in Disk Enclosures

Read mirror-disk with normal SCSI controller

Hans de bruin — Wed, 25 Apr 2007 02:55:31 GMT

As a way of doing disaster recovery, we use the disk mirror-set of a server as backup.

I unplug one of the disks of the mirror-set and replace it with a spare one.
Then I hook up that disk to a normal desktop with a SCSI card and a SCA to SCSI converter.
Then I can normally read the contents of the disk and make a ghost image of it.

This works fine with Dell servers (PERC3/DC raid controllers) but with HP servers I cannot read the disk.
It only shows an unallocated partition.

I have tried several different HP servers with different raid controllers, but they all give the same result.

Does anybody know why this is happening and how I can get past this?

Thanks.

Re: Read mirror-disk with normal SCSI controller

Rob Leadbeater — Wed, 25 Apr 2007 03:08:57 GMT

Hi,

I'm fairly certain you can't do this with disks that have been connected to a SmartArray controller.

These RAID controllers store their configuration on the disks when the array is initialised which will prevent the disk from being readable on a normal SCSI card.

To do what you want, you'll probably have to get hold of a SmartArray controller to use in your desktop, or use a spare HP server to create your Ghost image.

Hope this helps,

Regards,

Rob

Re: Read mirror-disk with normal SCSI controller

Hans de bruin — Wed, 25 Apr 2007 04:36:14 GMT

Thanks a lot for your help Rob.

I have some old Proliant 6500 servers around here and I am currently testing it with one.

I tried installing a Smart Array 3200 controller in a desktop (Dell GX110) here but that doesn't work. The desktop doesn't support PCI Data Bus Parity Checking and doesn't get past the BIOS.

Do you have any suggestions of which kind of desktops (mainboards) will work with Smart Array controllers?
That way I wouldn't have to rely on those old 6500 servers anymore.

Thanks again for your help. It's very interesting to get more info on those array controllers.

Re: Read mirror-disk with normal SCSI controller

Rob Leadbeater — Wed, 25 Apr 2007 06:10:06 GMT

Hi,

I'm not sure that a SmartArray controller will work in a non HP box... it might do, but I've never tried.

This link might be useful:

ftp://ftp.compaq.com/pub/products/servers/proliantstorage/arraycontrollers/compatability-matrix.pdf

as might this one:

http://h18004.www1.hp.com/products/servers/proliantstorage/arraycontrollers/index.html

Regards,

Rob

Re: Read mirror-disk with normal SCSI controller

Hans de bruin — Wed, 25 Apr 2007 06:30:51 GMT

Just finished making a ghost of a harddisk using an old 6500 server and it works like a charm.

It's just a matter of putting in the disk from an other server and it is automatically detected by the ACU and then you can read and write to it.

I will continue to test a bit more with adding a SA controller to a desktop but I don't think that will ever work because server mainboards are a bit more complex than desktop mainboards.

Thanks for your help on this.