RPi Adding USB Drives - Revision history

Ugh tC: Grammar and readability update.

2013-03-01T18:40:56Z

Grammar and readability update.

TrevorGowen at 18:23, 28 August 2012

2012-08-28T18:23:30Z

TrevorGowen: Powered USB hub may not be necessary. Added new section "Robust mounting of multiple USB flash drives"

2012-08-28T17:59:11Z

Powered USB hub may not be necessary. Added new section "Robust mounting of multiple USB flash drives"

Prpplague: moved Adding USB Drives to a Raspberry Pi to RPi Adding USB Drives: change title to fit with naming scheme

2012-07-13T20:30:47Z

moved Adding USB Drives to a Raspberry Pi to RPi Adding USB Drives: change title to fit with naming scheme

Ghans at 12:45, 29 June 2012

2012-06-29T12:45:31Z

Nr: added information on /etc/fstab

2012-06-21T10:13:55Z

added information on /etc/fstab

Jim Manley: /* Unmounting a Partition Before Drive Disconnection */

2012-05-14T09:17:07Z

‎Unmounting a Partition Before Drive Disconnection

Jim Manley: /* Mounting a Partition */

2012-05-14T09:16:03Z

‎Mounting a Partition

Jim Manley: Created page with "==USB Flash and Hard Drives== Sooner or later, you're going to run out of room on the SD card used to boot and run your Pi. One solution is to move to a larger SD card, but, the..."

2012-05-14T06:21:23Z

Created page with "==USB Flash and Hard Drives== Sooner or later, you're going to run out of room on the SD card used to boot and run your Pi. One solution is to move to a larger SD card, but, the..."

New page

==USB Flash and Hard Drives==
Sooner or later, you're going to run out of room on the SD card used to boot and run your Pi. One solution is to move to a larger SD card, but, the largest low-cost high-speed cards are 32 GBs for about US$20 ~ $45 (May 2012). However, there may be compatibility issues between these higher-capacity SD cards and the Pi, at least, temporarily. USB flash drives (aka "thumb" drives) can provide additional storage for about the same, or less, cost as an SD card of the same capacity. USB flash drives generally also have faster data transfer speeds than SD cards. Another option is to connect a USB hard disk drive, which can provide up to over a terabyte (1 TB) capacity and data transfer speeds well beyond 40 MBs/second, much larger and faster than SD cards or USB flash drives.
==Powered USB Hubs==
In any case, in order to expand the storage capacity, you will need to connect a powered USB hub to one of your Pi USB jacks, and then connect the USB drive to the hub. A USB hard drive can either have its own AC/mains power supply or it can have two USB plugs, and get a USB 2.0 hub with at least four expansion ports - more is better, within a reasonable cost. A four-port USB 2.0 hub will cost about US$7 - $15, and don't bother with a USB 3.0 hub, as the Pi only has a USB 2.0 interface.
==Mounting Drive Partitions==
You can plug in a USB flash or hard disk drive while the Pi is running without any problem. The USB device will be sensed by the Pi, however, it probably won't be added to the operating system's file system. That will require some manual intervention to "mount" the device onto the file system. A flash or hard drive may be configured with one, or more, partitions, which you can create yourself in the unlikely event that the drive doesn't already have any. Creating partitions is covered in a separate tutorial: [TBD]
===USB Drive Hierarchy===
Linux hardware devices are organized and identified by letters under the file system's device hierarchy, <code>/dev</code>. USB drives attached to the Pi are found under the file system as <code>/dev/sdX</code>, where "X" starts with the letter "a" representing the first USB drive, "b" for the second drive, "c" for the third, etc. The individual partitions on each drive are represented by incremented numbers, starting with "1". So, the first partition on the first USB drive is located in the file system as <code>/dev/sda1</code>, the second partition on that drive is <code>/dev/sda2</code>, the third partition on a third drive would be <code>/dev/sdc3</code>, etc.
===Mount Points===
In order to make a partition accessible to the file system, you need to use the Linux "mount" command, referencing the hardware (e.g., <code>/dev/hda1</code>) and a "mount point" in the file system, which is any empty directory, usually created for the purpose by the user. There is a canonical (i.e., standard) directory path where mount points are usually created: the <code>/mnt</code> directory. You can create a new directory under <code>/mnt</code> for each partition to be mounted, and it can be named anything you want as long as it doesn't contain any spaces. You might want to name it to correspond to the drive's physical characteristics, e.g., <code>/mnt/1GB_USB_flash</code>, or <code>/mnt/120GB_USB_hard_disk</code>.
===Mounting a Partition===
After creating the mount point for a partition, the only thing left to do is to actually mount the drive partition, e.g.:

<code>mount -o uid=pi,gid=pi /dev/sda1 /mnt/1GB_USB_flash</code>

where:

<code>-o</code> (lowercase letter "o", not the number zero) specifies that an option string follows

<code>uid=pi,gid=pi</code> specifies the user ID is user "pi" and the group ID is "pi" (note there are no spaces allowed between these terms)

<code>/dev/sda1</code> is the first partition on the first USB drive

<code>/mnt/1GB_USB_flash</code> is the mount point directory
===Operations on a Mounted Partition===
If all goes well, you will see nothing after pressing the Return key other than another command line prompt, which means there were no errors encountered during the mount process. You can then access the partition by referring it via /mnt/1GB_USB_flash/... where the "..." would be the file system path to the directories and files on which you want to perform an operation. For example, to list the details about the files at the top of the partition, you would simply type:

<code>ls -l /mnt/1GB_USB_flash</code>

To copy a file named "file1.txt" to another file named "file2.txt" in the directory "my_directory", you would type:

<code>cp /mnt/1GB_USB_flash/my_directory/file.txt /mnt/1GB_USB_flash/my_directory/file2.txt</code>

Of course, you can make this a lot simpler by just changing the current directory to my_directory like this:

<code>cd /mnt/1GB_USB_flash/my_directory</code>

To run an executable file "my_program.bin" while in that directory, you would type:

<code>./my_program.bin</code>

You can copy or move files and directories to or from any directory in the mounted partition by just referring to the appropriate path to that directory in the partition.
==Unmounting a Partition Before Drive Disconnection==
When you're done with a drive and want to disconnect it from the Pi, you should unmount the drive by using the "umount" command (notice there is no letter "n" between the "u" and the "m") and referring to the mount point:

<code>umount /mnt/1GB_USB_flash</code>
==Other mount and umount Features==
You can learn more about mount and umount features by typing <code>mount -h</code> or <code>mount --help</code>, <code>umount -h</code> or <code>umount --help</code>, or via their "man" (manual) pages by typing <code>man mount</code> or <code>man umount</code>.

← Older revision		Revision as of 12:45, 29 June 2012
Line 1:		Line 1:
		+	[[Category:RaspberryPi]]
		+
	==USB Flash and Hard Drives==		==USB Flash and Hard Drives==
	Sooner or later, you're going to run out of room on the SD card used to boot and run your Pi. One solution is to move to a larger SD card, but, the largest low-cost high-speed cards are 32 GBs for about US$20 ~ $45 (May 2012). However, there may be compatibility issues between these higher-capacity SD cards and the Pi, at least, temporarily. USB flash drives (aka "thumb" drives) can provide additional storage for about the same, or less, cost as an SD card of the same capacity. USB flash drives generally also have faster data transfer speeds than SD cards. Another option is to connect a USB hard disk drive, which can provide up to over a terabyte (1 TB) capacity and data transfer speeds well beyond 40 MBs/second, much larger and faster than SD cards or USB flash drives.		Sooner or later, you're going to run out of room on the SD card used to boot and run your Pi. One solution is to move to a larger SD card, but, the largest low-cost high-speed cards are 32 GBs for about US$20 ~ $45 (May 2012). However, there may be compatibility issues between these higher-capacity SD cards and the Pi, at least, temporarily. USB flash drives (aka "thumb" drives) can provide additional storage for about the same, or less, cost as an SD card of the same capacity. USB flash drives generally also have faster data transfer speeds than SD cards. Another option is to connect a USB hard disk drive, which can provide up to over a terabyte (1 TB) capacity and data transfer speeds well beyond 40 MBs/second, much larger and faster than SD cards or USB flash drives.

← Older revision		Revision as of 10:13, 21 June 2012
Line 23:		Line 23:

	<code>/mnt/1GB_USB_flash</code> is the mount point directory		<code>/mnt/1GB_USB_flash</code> is the mount point directory
		+
		+	===Mounting a Partition at Boot===
		+	To automatically mount a partition at boot time, the /etc/fstab file must be edited, and a line added for each partition and mountpoint:
		+
		+	neil@raspbian:~$ cat /etc/fstab
		+	proc /proc proc defaults 0 0
		+	/dev/mmcblk0p1 /boot vfat defaults 0 0
		+	#/dev/mmcblk0p3 none swap sw 0 0
		+	/dev/mmcblk0p4 /mnt/sdcard ext4 rw,defaults 0 0
		+	/dev/sda1 /mnt/usbdisk ext3 rw,defaults 0 0
		+	/dev/sda3 none swap sw 0 0
		+
		+	In this example, we are mounting one partition for read-write access at /mnt/usbdisk, and also moving the swap file from SD card to USB. The # character in the first column means that the rest of that line is treated as a comment. For more information see man fstab(5).

	===Operations on a Mounted Partition===		===Operations on a Mounted Partition===

@@ Line 2: / Line 2: @@
 ==USB Flash and Hard Drives==
-Sooner or later, you're going to run out of room on the SD card used to boot and run your Pi.  One solution is to move to a larger SD card, but, the largest low-cost high-speed cards are 32 GBs for about US$20 ~ $45 (May 2012).  However, there may be compatibility issues between these higher-capacity SD cards and the Pi, at least, temporarily.  USB flash drives (aka "thumb" drives) can provide additional storage for about the same, or less, cost as an SD card of the same capacity.  USB flash drives generally also have faster data transfer speeds than SD cards.  Another option is to connect a USB hard disk drive, which can provide up to over a terabyte (1 TB) capacity and data transfer speeds well beyond 40 MBs/second, much larger and faster than SD cards or USB flash drives.
+Sooner or later, you're going to run out of room on the SD card used to boot and run your Pi.  One solution is to move to a larger SD card, but, the largest low-cost high-speed cards are 32 GBs for about US$20 ~ $45 (May 2012).  However, there may be compatibility issues between these higher-capacity SD cards and the Pi, at least, temporarily.  USB flash drives (aka "thumb" drives) can provide additional storage for about the same, or less, cost as an SD card of the same capacity.  USB flash drives generally also have faster data transfer speeds than SD cards.  Another option is to connect a USB hard disk drive, which can provide over a terabyte (1 TB) in capacity and data transfer speeds well beyond 40 MBs/second, much larger and faster than SD cards or USB flash drives.
 ==Powered USB Hubs==
-In any case, in order to expand the storage capacity, you may need to connect a powered USB hub to one of your Pi USB jacks, and then connect the USB drive to the hub.  A USB hard drive can either have its own AC/mains power supply or it can have two USB plugs, and get a USB 2.0 hub with at least four expansion ports - more is better, within a reasonable cost.  A four-port USB 2.0 hub will cost about US$7 - $15, and don't bother with a USB 3.0 hub, as the Pi only has a USB 2.0 interface.  However, if you're running your Pi "headless" (ie. without keyboard, mouse or monitor) and remotely logging in via another computer, both USB jacks will be available for use with USB flash drives, without excessive drain on the Pi's power supply. ('''NB:''' Only tested on a 'B' model acquired July 2012)
+In order to expand the storage capacity, you may need to connect a powered USB hub to one of your Pi's USB ports, and then connect the USB drive to the hub.  A USB hard drive can either have its own AC/mains power supply or it will draw its power via the USB cable.  If it is the latter, then you will most certainly need a powered hub as the Pi may not have enough power for itself and extra devices.  A four-port USB 2.0 hub will cost about US$7 - $25 though do shop around as quality does vary.  Since the current Pi models only has a USB 2.0 interface so you do not need to buy a USB 3.0 device.
 ==Mounting Drive Partitions==
 You can plug in a USB flash or hard disk drive while the Pi is running without any problem.  The USB device will be sensed by the Pi, however, it probably won't be added to the operating system's file system.  That will require some manual intervention to "mount" the device onto the file system.  A flash or hard drive may be configured with one, or more, partitions, which you can create yourself in the unlikely event that the drive doesn't already have any.  Creating partitions is covered in a separate tutorial: [TBD]

@@ Line 4: / Line 4: @@
 Sooner or later, you're going to run out of room on the SD card used to boot and run your Pi.  One solution is to move to a larger SD card, but, the largest low-cost high-speed cards are 32 GBs for about US$20 ~ $45 (May 2012).  However, there may be compatibility issues between these higher-capacity SD cards and the Pi, at least, temporarily.  USB flash drives (aka "thumb" drives) can provide additional storage for about the same, or less, cost as an SD card of the same capacity.  USB flash drives generally also have faster data transfer speeds than SD cards.  Another option is to connect a USB hard disk drive, which can provide up to over a terabyte (1 TB) capacity and data transfer speeds well beyond 40 MBs/second, much larger and faster than SD cards or USB flash drives.
 ==Powered USB Hubs==
-In any case, in order to expand the storage capacity, you will need to connect a powered USB hub to one of your Pi USB jacks, and then connect the USB drive to the hub.  A USB hard drive can either have its own AC/mains power supply or it can have two USB plugs, and get a USB 2.0 hub with at least four expansion ports - more is better, within a reasonable cost.  A four-port USB 2.0 hub will cost about US$7 - $15, and don't bother with a USB 3.0 hub, as the Pi only has a USB 2.0 interface.
+In any case, in order to expand the storage capacity, you may need to connect a powered USB hub to one of your Pi USB jacks, and then connect the USB drive to the hub.  A USB hard drive can either have its own AC/mains power supply or it can have two USB plugs, and get a USB 2.0 hub with at least four expansion ports - more is better, within a reasonable cost.  A four-port USB 2.0 hub will cost about US$7 - $15, and don't bother with a USB 3.0 hub, as the Pi only has a USB 2.0 interface.  However, if you're running your Pi "headless" (ie. without keyboard, mouse or monitor) and remotely logging in via another computer, both USB jacks will be available for use with USB flash drives, without excessive drain on the Pi's power supply. ('''NB:''' Only tested on a 'B' model acquired Aug. 2012)
 ==Mounting Drive Partitions==
 You can plug in a USB flash or hard disk drive while the Pi is running without any problem.  The USB device will be sensed by the Pi, however, it probably won't be added to the operating system's file system.  That will require some manual intervention to "mount" the device onto the file system.  A flash or hard drive may be configured with one, or more, partitions, which you can create yourself in the unlikely event that the drive doesn't already have any.  Creating partitions is covered in a separate tutorial: [TBD]
@@ Line 64: / Line 64: @@
 ==Other mount and umount Features==
 You can learn more about mount and umount features by typing <code>mount -h</code> or <code>mount --help</code>, <code>umount -h</code> or <code>umount --help</code>, or via their "man" (manual) pages by typing <code>man mount</code> or <code>man umount</code>.

@@ Line 45: / Line 45: @@
 When you're done with a drive and want to disconnect it from the Pi, you should unmount the drive by using the "umount" command (notice there is no letter "n" between the "u" and the "m") and referring to the mount point:
-<code>umount /mnt/1GB_USB_flash</code>
+<code>sudo umount /mnt/1GB_USB_flash</code>
 ==Other mount and umount Features==
 You can learn more about mount and umount features by typing <code>mount -h</code> or <code>mount --help</code>, <code>umount -h</code> or <code>umount --help</code>, or via their "man" (manual) pages by typing <code>man mount</code> or <code>man umount</code>.

@@ Line 12: / Line 12: @@
 After creating the mount point for a partition, the only thing left to do is to actually mount the drive partition, e.g.:
-<code>mount -o uid=pi,gid=pi /dev/sda1 /mnt/1GB_USB_flash</code>
+<code>sudo mount -o uid=pi,gid=pi /dev/sda1 /mnt/1GB_USB_flash</code>
 where:
@@ Line 23: / Line 23: @@
 <code>/mnt/1GB_USB_flash</code> is the mount point directory
 ===Operations on a Mounted Partition===
 If all goes well, you will see nothing after pressing the Return key other than another command line prompt, which means there were no errors encountered during the mount process.  You can then access the partition by referring it via /mnt/1GB_USB_flash/... where the "..." would be the file system path to the directories and files on which you want to perform an operation.  For example, to list the details about the files at the top of the partition, you would simply type: