[solved] Re: fstab entries for two different pendrives?
On Saturday 26 August 2006 11:56, Rodolfo Medina wrote:
>> I have the following problem:
>> yesterday I bought a new 256 MB pendrive, that wants to be mounted
>> as `/dev/sda' whereas the other one I have wants `/dev/sda1'.
>> Now, if in /etc/fstab I put the sda entry first, then can't mount sda1;
>> and vice versa, if I put sda1 first then I can't mount sda.
Alan Chandler <alan@chandlerfamily.org.uk> writes:
> Use udev to recognise the pendrive from its manufactures name, and create a
> symlink (or actual device) called /dev/flash. Mount that in /etc/fstab
>
> [...]
>
Rodolfo:
>> I forgot to say that my kernel is the 2.4, so udev is not for me - is it?
Alan:
> Why not upgrade?
Rodolfo:
> Because, very likely I should re-learn and re-do all I can do with Debian,
> re-write many howtos and packages installations.
> Hard long work.
>
> [...]
>
>> fstab alone should be sufficient to mount any device.
>> I'd like to understand *why* it can't manage two sd* devices together,
>> or what's the proper way to make it do.
Alan:
> The problem is (and one of the reasons udev was invented) is that either you
> dynamically allocate device ids as they are hotplugged, or you have to
> pre-allocate a device for every possible device (not really realistic).
>
> Once you have dynamic allocation of devices, the order of plugging them in
> matters, and that prevents you knowing which is going to be sda and which is
> going to be sdb.
Rodolfo:
> Maybe the problem might be worked out if I could change the old pen's
> device into sda as well?
> I noticed that my old pendrive can only be mounted as /dev/sda1,
> whereas the new one indifferently with /dev/sda or /dev/sdb.
> If both pendrives had the same device then I could put just one entry
> in fstab and the plugging order would not be very important.
> I do want to use both, but one at a time.
> Is there a way one can change /dev/sda1 into /dev/sda or /dev/sdb
> for the first pendrive?
Alan:
> possibly, but this is pure speculation on my part. when your pen without
> partiions is in /dev/sda, run fdisk /dev/sda and create one partition on it.
> Then use mkfs -t vfat to format /dev/sda1
It seems to be solved now.
I'm reoprting the whole procedure.
Thanks,
Rodolfo
---------------------------------------------------------
I bought a new pen drive: the old one required `/dev/sda1'
and the new one /dev/sda.
This means that there was some unnecessary partition in the old pen drive.
This created problems when I wanted to mount both pen drives
(see below), so I wanted to delete that partition. I did:
# apt-get install dosfstools
. I canceled the `sda1' entries from fstab, then rebooted.
I inserted the old pen drive, and:
# fdisk /dev/sda
, and deleted the existing partition with `d'.
Then I created a new one with: `n', `p', `1', and first and last
cylinder the default ones. Then I did: `t' and `6' to select fat16
as partition type. I did `w' to save change and exit fdisk.
Then I did:
# mkfs.msdos -I /dev/sda
. Now the old pen drive required /dev/sda just as the new one.
In fstab I replaced the line:
/dev/sda1 /mnt/sda1 vfat sync,rw,user,noauto 0 0
with the two:
/dev/sda /mnt/sda vfat sync,rw,user,noauto 0 0
/dev/sdb /mnt/sdb vfat sync,rw,user,noauto 0 0
. Now, when I wanted to mount a pen drive, I did:
$ mount /mnt/sda
. If I wanted to mount both pen drives, I did
$ mount /mnt/sda
for the first one, and
$ mount /mnt/sdb
for the second one. This order is always valuable: after inserting a pen drive
in /dev/sda, the second one will be in /dev/sdb. This is true also when using
`parted' and `fdisk', even when the devices are not actually mounted:
if you use parted with the second pen drive, you have to start it with:
# parted /dev/sdb
, and fdisk with
# fdisk /dev/sdb
. The above problem arised because the old pen drive was /dev/sda1,
and this made it impossible to edit fstab in a proper way to mount both.
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