topic Re: Mirror breaking in Integrity Servers

Mirror breaking

Mirror breaking — Fri, 07 Dec 2007 08:50:54 GMT

Hi All,

We have a rx3600 server with p400 SAS controller ,configured hardware mirror.Now i want to break that hardware mirror and i want to use that hard disk to another VG.please give me the suggestion how to break hardware mirroring in SAS controller.

Re: Mirror breaking

yulianto piyut — Fri, 07 Dec 2007 08:55:01 GMT

LVM mirror that you mean ?
just lvreduce -m 0 /dev/vgxx/lvxx /dev/dsk/cxtxdx, vgreduce /dev/vgxx /dev/dsk/cxtxdx

-yut-

Re: Mirror breaking

Torsten. — Fri, 07 Dec 2007 11:03:00 GMT

The P400 is a smartarray controller that can do several RAID configs.

I'm not aware of an option to reduce anything (except spares), but you can delete and recreate.

run "saconfig" without any option to see all possibilities.

Re: Mirror breaking

Prashanth.D.S — Sat, 08 Dec 2007 09:59:37 GMT

Hi,

I dont think there is any difference for sas disks when it comes to breaking of mirror.

#lvreduce -m 0 /dev/vgxx/lvolx /dev/dsk/cxtxd0

#vgreduce /dev/vgxx /dev/dsk/cxtxd0

But when you need to replace a failed disk the sasmgr comes into picture.

When a disk fails, and a new disk is put into the same bay that the failed disk came out of, the SAS controller knows it is a different disk by its SAS address. The O/S driver assigns the next available target for the hardware path (viewed with ioscan) and special device file if insf -e is executed. The sasmgr(1M) command must be used with the â replace_tgtâ command to replace the special device file used by LVM with the hardware path to the new disk

Best Regards,
Prashanth

Re: Mirror breaking

Torsten. — Mon, 10 Dec 2007 06:26:04 GMT

IMHO the previous message does not apply.

The Smartarray P400 is a hardware RAID controller and you can handle it by sautil and saconfig together with the controller device file like /dev/cissx.

Each created logical drive is presented as a single disk device even it is a hardware mirrored RAID1 or RAID 5 or RAID 6 ... or whatever.