> -----Original Message----- > From: centos-bounces at centos.org On Behalf Of Jussi Hirvi > Sent: 30/04/2011 10:31 > To: CentOS mailing list > Subject: [CentOS] Identifying physical disks > > 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 How about: ls -l /dev/disk/by-id which on my system gives me: lrwxrwxrwx 1 root root 9 Mar 6 14:34 scsi-SATA_SAMSUNG_HD154UIS1XWJ1BZ900317 -> ../../sdc lrwxrwxrwx 1 root root 9 Mar 6 14:34 scsi-SATA_SAMSUNG_HD154UIS1XWJ1BZ900318 -> ../../sdb lrwxrwxrwx 1 root root 9 Mar 6 14:34 scsi-SATA_SAMSUNG_HD154UIS1XWJ9CZA00454 -> ../../sdd which are my three identical Samsung HD154UI disks. Their serial numbers are the S1XWJ... bits at the end. hth Andy