USBDisks
USB Disks
SME will automatically mount connected USB disk drives into the /media folder. Auto-mounting will be performed based on the specific USB port used to connect your drives unless you use another method to specify mount points.
This means that if you insert USB drive 'A', it should auto-mount to /media/usbdisk. If you now dismount this disk and mount drive 'B' in the same USB port, it, too, will auto-mount to /media/usbdisk. Additionally, if you connect drive 'A' to another USB port, it may auto-mount to /media/usbdisk1.
The easiest way to avoid this behavior is to provide a label for each of your USB drives, and specify the desired mount point in /etc/fstab based on the drive label.
Supported FileSystems
ext2/ext3
- recommended for USB drives intended for use only on SME
- works great under Linux
- supports hard links, symlinks
- can be read under Windows using explore2fs from http://www.chrysocome.net/explore2fs
- File & Disk size limits depend on the block size used when formatting the disk. SME defaults to a 1K block size.
1K block size: 16GB max file size, 2TB max disk size
2K block size: 256GB max file size, 8 TB max disk size.
4K block size: 2TB max file size, 16 TB max disk size
fat32/vfat
- pre-configured on most USB hard drives
- supported natively by Windows
- (2^32)-1 byte ( 4GB - 1 byte) maximum file size
- Windows 2000 format and Windows XP Setup's format will not create a fat32 volume larger than 32 GB
- Maximum disk size dependent on cluster size. 32KB Clusters would allow a disk of approximately 8TB
Identifying your USB drive
After connecting your USB drive, execute the command
mount
and look for anything mounted in /media/???.
If your drive did not auto-mount, search /var/log/messages for the kernel commands related to your device using:
egrep "(kernel|fstab|scsi).*(usb|USB)" /var/log/messages
You should have a line logged by fstab-sync giving the auto-mount folder created and the device name for your new device that looks like this:
Sep 23 17:11:14 office fstab-sync[32193]: added mount point /media/usbdisk1 for /dev/sdd1
You should now be able to mount your USB drive using the values found in /var/log/messages. In our example, that would mean:
mount /media/usbdisk1
or
mount /dev/sdd1
Formatting your USB drive
ext3
- Copied with slight changes from Affa#Alternatively_setup_a_USB_drive
- Connect a USB hard disk to the USB Bus. Now you must determine what device the kernel has assigned to the drive. View the /var/log/message and search for Initializing USB Mass Storage driver. A few lines below you'll find the name of the device. In this example it is sdc. Replace /dev/sdc by your device in following instructions. Use the fdisk program to create a linux partition fdisk /dev/sdc You'll most likely find an existing vfat dos partition, which you have to delete first. In the following we assume, that you have created a single partition /dev/sdc1.
- Now format the drive with an ext3 filesystem mkfs.ext3 -L MyLabel /dev/sdc1
- Make the mount point mkdir -p /mnt/affadevice
- Customize /etc/fstab as shown here: Customizing fstab
- Mount the drive mount /mnt/affadevice
- Crosscheck your work using the df command df
vfat
It's probably easier to format your vfat drive on your windows system. You *must* have one, or you wouldn't be using this format...
If that sounds unhelpful, you could try (warning, untested!):
mkfs.vfat -n MyLabel /dev/sdd1
labeling your USB drive
ext3
e2label /dev/sdd1 MyLabel
vfat
Linux uses 'mtools' to manage FAT, FAT32, and VFAT partitions. 'mtools' uses drive letters to access devices. These drive letters must be defined in /etc/mtools.conf before any of the mtools will work. You can create a definition for your USB drive using a command like this one (be sure to replace /dev/sdd1 with the device name identified above for your USB drive!):
echo 'drive e: file="/dev/sdd1"' >> /etc/mtools.conf
Once you have created the drive letter in mtools.conf you can view or edit the disk label using the following commands.
Show the current label:
mlabel -s e:
Clear the volume label:
mlabel -c e:
Assign a new volume label:
mlabel e:MyLabel
Customizing fstab
Add the following line to the /etc/fstab
LABEL=MyLabel /mnt/affadevice ext3 defaults
- Replace 'ext3' with 'vfat' if your drive is formatted as vfat.
- Replace /mnt/affadevice with the folder in which you want your USB drive mounted
Mount your disk automatically at boot-up
Use the following commands to create a script that will run at each re-boot if you want to re-mount your USB disk automatically:
cat <<EOF > /etc/e-smith/events/local/S95mount_USB #! /bin/sh mount LABEL=MyLabel EOF chmod +x /etc/e-smith/events/local/S95mount_USB
Once the script exists you can add additional mount commands by editing S95mount_USB using:
pico -w /etc/e-smith/events/local/S95mount_USB
More Information
- There is a contrib for managing USB disks: http://forums.contribs.org/index.php?topic=35466.0
- Here is a link to the Microsoft KB article on fat volume size limits:
http://support.microsoft.com/kb/314463
Summary: 32GB limit during XP Setup, 8 Terabyte otherwise - Here is a link to an old MS technote about fat32 limits with 'format' under Win2K:
http://www.microsoft.com/technet/prodtechnol/windows2000serv/reskit/prork/prdf_fls_pxjh.mspx?mfr=true
Summary: format under Windows 2000 has a 32GB limitation.
