From mboxrd@z Thu Jan 1 00:00:00 1970 From: Colin McCabe Subject: Re: Fwd: Identify SATA Disks Date: Thu, 24 May 2007 11:53:15 -0400 Message-ID: <4655B4EB.5050102@gmail.com> References: <8c4e120705230023v71a2ffa3p182f1e02ccb9cd54@mail.gmail.com> <8c4e120705231629q727718f2yb0704ff33b7012c@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <8c4e120705231629q727718f2yb0704ff33b7012c@mail.gmail.com> Sender: linux-raid-owner@vger.kernel.org Cc: Linux-Raid List-Id: linux-raid.ids lewis shobbrook wrote: > Hi All, > I'm wondering if anyone has discovered any nice tricks to assist in > identification of hdd devices. > I have an 8 bay hotswap array, pretty lights and have been wondering > what others out there might be doing to determine which disk in an > array is which. > > I've noted that device allocation can change with the generation of > new initrd's and installation of new kernels; i.e. /dev/sdc becomes > /dev/sda depending upon what order the modules load etc. > I'm wondering if one could send a looped read/write task to a swap > partition or something to determine which the device is? > The device UUID in the RAID superblock doesn't change across a reboot. If you run mdadm --examine on the disk, you should see something like [root@ss-110 root]# mdadm --examine /dev/sda /dev/sda: Magic : a92b4efc Version : 01 Feature Map : 0x0 Array UUID : eab59421:6ddd9761:05e6ca46:d2342b03 Name : 408088ETX1:single Creation Time : Mon Dec 4 21:25:55 2006 Raid Level : raid1 Raid Devices : 2 Device Size : 117210096 (55.89 GiB 60.01 GB) Array Size : 117187500 (55.88 GiB 60.00 GB) Used Size : 117187500 (55.88 GiB 60.00 GB) Super Offset : 117210224 sectors State : active ==>Device UUID : 06795ada:d2fb18a1:2e7de09f:af66a7e3 <== Update Time : Thu May 24 11:49:21 2007 Checksum : 7a695b9f - correct Events : 4346975 That number should always uniquely identify your disks. Maybe even a better way is to run: [root@ss-110 root]# smartctl -d ata /dev/sda -i smartctl version 5.36 [i686-pc-linux-gnu] Copyright (C) 2002-6 Bruce Allen Home page is http://smartmontools.sourceforge.net/ === START OF INFORMATION SECTION === Device Model: FUJITSU MHV2060BH ====> Serial Number: NW02T6826LM5 <==== Firmware Version: 00000028 User Capacity: 60,011,642,880 bytes Device is: Not in smartctl database [for details use: -P showall] ATA Version is: 7 ATA Standard is: ATA/ATAPI-7 T13 1532D revision 4a Local Time is: Thu May 24 11:51:16 2007 EDT SMART support is: Available - device has SMART capability. SMART support is: Enabled That serial number never changes, even if you wipe the disk. Colin > Cheers, > > Lew