Michael Harris schrieb:
Hi,
I have just built a Raid 5 array using mdadm and while it is running fine I have a question, about identifying the order of disks in the array.
In the pre sata days you would connect your drives as follows:
Primary Master - HDA
Primary Slave - HDB
Secondary - Master - HDC
Secondary - Slave -HDD
So if disk HDC failed i would know it was the primary disk on the secondary controller and would replace that drive.
My current setup is as follows
MB Primary Master (PATA) Primary Master - Operating System
The array disks are attached to:
MB Sata port 1
MB Sata port 2
PCI card Sata port 1
When i setup the array the OS drive was SDA and the other SDB,SDC,SDD.
Now the problem is everytime i reboot, the drives are sometimes detected in a different order, now because i mount root via the UUID of the OS disk and the kernel looks at the superblocks of the raided drives everything comes up fine, but I'm worried that if i move the array to another machine and need to do a mdadm --assemble that i won't know the correct order of the disks and what is more worrying if i have a disk fail say HDC for example, i wont know which disk HDC is as it could be any of the 5 disks in the PC. Is there anyway to make it easier to identify which disk is which?.
If the drives have any LEDs, the most reliable way would be:
dd if=/dev/drive of=/dev/null
Then look which LED is the one which blinks the most.
--
Tomasz Chmielewski
http://wpkg.org
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