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QuantumFoam
Tux's lil' helper
Joined: 07 Jun 2003
Posts: 100
Location: San Clemente, CA
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 Posted: Fri Apr 04, 2008 11:49 pm Post subject: USB Drives Not Consistently Assigned in /dev |
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Hi. I've been having a problem that's more of an annoyance than a real issue, but I was wondering if anyone could help me out. I have three USB2 disk drives, all connected in parallel through a USB2 hub, and I have them assigned (in fstab) to mount to various mountpoints in /mnt. The trouble is, my system is inconsistent in the assignment of drive to /dev node (I think node is the word to use here).
As an example, in fstab, I have a listing for /dev/sda1 to be mounted to /mnt/itchy, for /dev/sdb1 to be mounted to /mnt/scratchy, and /dev/sdc1 to be mounted to /mnt/poochy. The next time I reboot, the drive that was assigned to sda1 will be assigned to sdb1, sdc1 to sda1, and sdb1 to sdc1, and each physical drive will end up on the wrong mountpoint. There is no consistency between boots. Is there a way to assign a /dev node to a drive with a certain serial number, or is there perhaps a better solution? Thanks in advance for any insight you may provide. |
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jstead1
Guru
Joined: 01 Aug 2003
Posts: 427
Location: Oswego, NY where the snow is deep
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| Posted: Fri Apr 04, 2008 11:57 pm Post subject: |
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try typing
mount drive udev script
into google.
lots of examples
_________________
jim |
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wjb
l33t
Joined: 10 Jul 2005
Posts: 644
Location: Fife, Scotland
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| Posted: Sat Apr 05, 2008 11:11 am Post subject: |
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Also, there are device specific names which get created in subdirectories of /dev/disk
The names are quite long, but they're ok for fstab. |
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Monkeh
Veteran
Joined: 06 Aug 2005
Posts: 1656
Location: England
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| Posted: Sat Apr 05, 2008 1:52 pm Post subject: |
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Use filesystem labels. See fstab and tune2fs man pages.
| wjb wrote: | Also, there are device specific names which get created in subdirectories of /dev/disk
The names are quite long, but they're ok for fstab. |
They're not trustworthy with USB devices. |
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wjb
l33t
Joined: 10 Jul 2005
Posts: 644
Location: Fife, Scotland
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| Posted: Mon Apr 07, 2008 6:08 pm Post subject: |
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| Just curious but why is it untrustworthy? The by-id directory picks up the manufacturer, model, and serial number the same as udevinfo gives out. |
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Monkeh
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Joined: 06 Aug 2005
Posts: 1656
Location: England
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| Posted: Mon Apr 07, 2008 8:36 pm Post subject: |
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| wjb wrote: | | Just curious but why is it untrustworthy? The by-id directory picks up the manufacturer, model, and serial number the same as udevinfo gives out. |
Yes, and the serial number is not reliable. I have two identical drives, with different serial numbers (obviously), and udev cannot tell the difference. As such, you cannot rely on it. |
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wjb
l33t
Joined: 10 Jul 2005
Posts: 644
Location: Fife, Scotland
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| Posted: Mon Apr 07, 2008 9:37 pm Post subject: |
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| @Monkey: So do you reckon its udev or the manufacturer who's got it wrong? |
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Monkeh
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Joined: 06 Aug 2005
Posts: 1656
Location: England
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| Posted: Mon Apr 07, 2008 11:57 pm Post subject: |
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| wjb wrote: | | @Monkey: So do you reckon its udev or the manufacturer who's got it wrong? |
I don't know, all I know is both report the same serial number (it's fake), and udev can't handle it properly. It can't be trusted with USB devices, as far as I'm concerned. I don't trust udev much anyway. |
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