[CentOS] Identifying physical disks

Sat Apr 30 21:29:15 UTC 2011
Kay Diederichs <kay.diederichs at uni-konstanz.de>

On 04/30/2011 11:30 AM, Jussi Hirvi wrote:
> I am sure this is really simple.
> I have a setup of 2 disks (sda, sdb) which are outwardly identical, and
> are mirrors of each other. Together they form 3 raid1 devices. Both
> disks can boot.
> Now sda has bad sectors, and I should replace it. But which one of the
> physical disks is sda??
> The machine boots fine from either one of the disks, (and the booting
> disk of course is always called sda).
> In the messages log I see entries like this:
> Apr 29 02:21:07 a134-224 kernel: ata2: SATA link up 3.0 Gbps (SStatus
> 123 SControl 300)
> By noticing which SATA link (ata1, ata2) is up and which is down, I can
> find out which physical disk is connected to ata1 and which to ata2.
> If both disks are connected, will the hd in ata1 become sda, and the hd
> in ata2 become sdb??
> - Jussi

hdparm -tT /dev/sda
and identify sda - it is the one with the blinking LEDs.