Hi all,
I have a box, until warranty (I may not open it) and 2 external USB hard drives.
My perfect solution is to open the box, plug the drives on the SATA slots, and use them.
Unfortunately, I'll have to fall back to the cheap solution: I would like to use each external drive as physical volume (PV) and then "join" them as a VG in order to use a LVM composed by internal drives and the externals.
This is not for a "very secure" storage, just for a low reliability quantity temporary one: I just need it to work for 3-4 weeks with potential power cycles.
How to get the USB external drives to be detected in always the same order, so that they always get the same "name"? /dev/sdX fixed to them? That way, the LVM wont be messed...
Thank you.
On 04/23/2012 09:21 AM, Mihamina Rakotomandimby wrote:
How to get the USB external drives to be detected in always the same order, so that they always get the same "name"? /dev/sdX fixed to them? That way, the LVM wont be messed...
Perhaps you can use UUIDs for that like Fedora is already doing. See man uuidgen for more info about a UUID. Assign each USB drive a unique UUID and use those UUIDs (instead of /dev/sdX) in /etc/fstab.
Regards, Patrick
On 04/23/2012 09:02 AM, Patrick Lists wrote:
How to get the USB external drives to be detected in always the same order, so that they always get the same "name"? /dev/sdX fixed to them? That way, the LVM wont be messed...
Perhaps you can use UUIDs for that like Fedora is already doing. See man
lvm does that anyway, does it not ? ( or has done in recent memory )
the drive ordering will not matter as long as the bios isnt mapping the usb disk as sda and/or trying to inject them into boot ordering
I suspect Mihamina is trying to fix a non-existant problem :)
- KB
On Mon, 2012-04-23 at 11:43 +0100, Karanbir Singh wrote:
On 04/23/2012 09:02 AM, Patrick Lists wrote:
How to get the USB external drives to be detected in always the same order, so that they always get the same "name"? /dev/sdX fixed to them? That way, the LVM wont be messed...
Perhaps you can use UUIDs for that like Fedora is already doing. See man
lvm does that anyway, does it not ? ( or has done in recent memory )
+1 Each PV is assigned a GUID. And the VG is reassembled dynamically. So don't worry about it.
That is just yet another stupid problem LVM eliminates.
On Monday, April 23, 2012 06:43:12 AM Karanbir Singh wrote:
the drive ordering will not matter as long as the bios isnt mapping the usb disk as sda and/or trying to inject them into boot ordering
FWIW, and for the archives, we have a Dell Precision 690 that does exactly that. I have a Seagate GoFlex 1TB 2.5 inch drive with both USB and FW800 'dongles' that I use for data interchange between a Macbook and the 690. The drive is partitioned GPT (for the booting of Mac OS X on the Macbook as a recovery system), and has four partitions.
If I boot the 690 with this particular drive plugged in, it hangs the 690's BIOS boot completely. Removing the USB boot device from the boot order doesn't help. Don't know why, and haven't tried to more thoroughly determine if it's the EFI partition or the boot code for Mac OS X or what. No splash screen comes up, the BIOS just hangs after AHCI enumeration (the last set of interfaces in the machine). The 690 is normally capable of USB boot; I used my CentOS 6.2 install USB key with my self-generated Dual Layer ISO on it to do the initial installation.
Again, FWIW and for the archives in case someone sees something similar with USB bootable devices getting in the way of normal boot.
On 23.4.2012 09:21, Mihamina Rakotomandimby wrote:
How to get the USB external drives to be detected in always the same order, so that they always get the same "name"? /dev/sdX fixed to them? That way, the LVM wont be messed...
lvm cares about device names? I always thought lvm works with uuid's internally.
On Mon, 2012-04-23 at 13:06 +0200, Markus Falb wrote:
On 23.4.2012 09:21, Mihamina Rakotomandimby wrote:
How to get the USB external drives to be detected in always the same order, so that they always get the same "name"? /dev/sdX fixed to them? That way, the LVM wont be messed...
lvm cares about device names? I always thought lvm works with uuid's internally.
It does.
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Adam Tauno Williams -
Karanbir Singh -
Lamar Owen -
Markus Falb -
Mihamina Rakotomandimby -
Patrick Lists