Mailinglist Archive: opensuse (2114 mails)

[Bill Merriam <lists@xxxxxxxxxxxxxxx>]

Fergus Wilde wrote:
> Hello all,
>
> can anyone recommend, from personal successful experience, any of the
> very large capacity (circa 1 TB) USB external hard drives for use with
> Linux? I ask because I cannot find a retailer in the UK who will say
> they will accept a return if the product doesn't work with Linux.
> Anyone who can give me a model name/ number available in the UK would
> be specially useful. I would buy a simple 'fill-it-yourself'
> enclosure, but many of these appear to have non-adjustable limits on
> the size of disk they will read.
Fergus,

I am in the US, not the UK.  I have had good success with 750GB Seagate
Freeagent, with OpenSuSE 11.0 and an XFS filesystem.  I have a "Desktop"
model (USB only) and a  "Pro" model (with USB,  firewire and ESATA). 
When I plug them in they show up in /dev/disk/by-id like this:

/dev/disk/by-id/usb-Seagate_FreeAgentDesktop_5QK04QLZ-0:0       
/dev/disk/by-id/usb-Seagate_FreeAgentDesktop_5QK04QLZ-0:0-part1
/dev/disk/by-id/usb-Seagate_FreeAgent_Pro_9QK0EGL9-0:0
/dev/disk/by-id/usb-Seagate_FreeAgent_Pro_9QK0EGL9-0:0-part1

The "random" part is the serial number.  They also show up in
/dev/disk/by-label (because I labeled the filesystem).

/dev/disk/by-label/UsbBackup 
/dev/disk/by-label/UsbMedia

This becomes important because the drive name they are assigned such as
/dev/sdb1 or /dev/sdc1 depends on what order they are plugged in, but
the /dev/disk/by-label and /dev/disk/by-id does not.

I put this in /etc/auto.misc:

usbdrive     -fstype=xfs        :/dev/disk/by-label/UsbBackup
usbmedia    -fstype=xfs        :/dev/disk/by-label/UsbMedia

The drive spins down after 15 minutes (you can set the time with hdparm)
and disappears.  When my backup program runs and writes to
/misc/usbdrive the correct drive spins up and is mounted in the right
place.  15 minutes after the backup program ends it spins down again. 
You can also spin it down using hdparm.

It comes formated with NTFS and a special windows driver to spin it up
and a silly windows utility to set the spin down time.  I reformatted to
XFS which is fast and supports huge file systems.  The drives in the
enclosures are SATA and if need be you can remove them and plug them
into another SATA interface or put a new drive in the enclosure. 

If you are using an earlier kernel than opensuse 11.0 then you may need to put 
the following into /etc/udev/rules.d/local.rules.

# Seagate FreeAgent allow_restart fix (i/o errors)
SUBSYSTEMS=="scsi",DRIVERS=="sd",ATTRS{vendor}=="Seagate*",ATTRS{model}=="FreeAgent*",RUN+="/bin/sh
 -c 'echo 1 > /sys/class/scsi_disk/%k/allow_restart'"

It is vastly faster and cheaper to use these drives for backups than to
use tape.  Once you understand how to use them with Linux there are no
worries.

Bill
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