USB and raid... Device names change

2006-09-18 Thread Eduardo Jacob

Hi

I don't know if question is really under your scope, but anyway I 
haven't got an answer in other places...


After experimenting poor reliability of hard disk effects, I have 
been trying to add a RAID1 setup to my silent EPIA based server with 
two IDE to USB 2.0 boxes with identical IDE disks inside. I followed 
advices around there and everything seemed to work fine: array was 
reconstructing and it finally get synced. Later I tried it and began 
copying files to the mounted partition. I decided to see how good and 
glamorous was RAID and switched off and on one of the disks... To my 
surprise, when the drive was switched again on, it was detected again 
and assigned a new device name (originally sda and sdb, now sdb and 
sdc)... Logically the array didn't synced.


All this with ubuntu dapper fully updated.

I began reading and I thought the solution was tweeking udev to 
create symbolink links to whichever the sd name was.


This is the 10-local.rules I finally put in /etc/udev

BUS==usb, KERNEL==sd*, SYSFS{serial}==DEF10A7350A2, NAME=%k, 
SYMLINK+=raid11%n
BUS==usb, KERNEL==sd*, SYSFS(serial)==DEF10A84811F, NAME=%k, 
SYMLINK+=raid12%n


It created succsefully a /dev/raid11, /dev/raid111, /dev/raid12 and 
/dev/raid121


Which apperar as

lrwxrwxrwx 1 root root 3 Sep 16 00:19 /dev/raid11 - sdb
lrwxrwxrwx 1 root root 4 Sep 16 00:19 /dev/raid111 - sdb1
lrwxrwxrwx 1 root root 3 Sep 16 00:19 /dev/raid12 - sda
lrwxrwxrwx 1 root root 4 Sep 16 00:19 /dev/raid121 - sda1


I even sucessfully created an array using partitions /dev/raid111, 
and /dev/raid121


this is the mdadm.conf I am using:

DEVICE /dev/raid111 /dev/raid121
ARRAY /dev/md0 level=raid1 num-devices=2 
UUID=1369e13f:eb4fa45c:6d4b9c2a:8196aa1b


The problem is that raid software doesn't take in count those names 
and uses the low level name. Here is what you get when you shutdown 
and switch on one of the disks...


[EMAIL PROTECTED]:~$ cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sda1[2](F) sdb1[0]
293033536 blocks [2/1] [U_]

An this the way the links are now...

lrwxrwxrwx 1 root root 3 Sep 16 00:19 /dev/raid11 - sdb
lrwxrwxrwx 1 root root 4 Sep 16 00:19 /dev/raid111 - sdb1
lrwxrwxrwx 1 root root 3 Sep 16 00:46 /dev/raid12 - sdd
lrwxrwxrwx 1 root root 4 Sep 16 00:46 /dev/raid121 - sdd1

Any suggestions?

Best regards and thank you for your outstanding work.

Eduardo

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Re: USB and raid... Device names change

2006-09-18 Thread dean gaudet
On Tue, 19 Sep 2006, Eduardo Jacob wrote:

 DEVICE /dev/raid111 /dev/raid121
 ARRAY /dev/md0 level=raid1 num-devices=2 
 UUID=1369e13f:eb4fa45c:6d4b9c2a:8196aa1b

try using DEVICE partitions... then mdadm -As /dev/md0 will scan all 
available partitions for raid components with 
UUID=1369e13f:eb4fa45c:6d4b9c2a:8196aa1b.  so it won't matter which sdX 
they are.

-dean
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