setting up a server as a hdd wiper

[dcody]

Hello - I am trying to use an intel based 2u sata server as a hdd wiper/formater. I have about 150 hdd's that I need to wipe and prep for resale. I have installed ubuntu 12.10 on a 160 sata drive in bay one (has a total of 8 bays).

It would be ideal if I could load the bays with drives and set it up to wipe one after the other or all at once.

Currently I don't know how to get ubuntu to recognize the drives I want to wipe.

I am a 10 year ubuntu user and a novice under the hood. I have very little server experience.

I have been searching but I am not finding anything that matches my situation.

Anyone have an idea how this could work out. Thanks a ton.

[Wim Sturkenboom]

Check with sudo fdisk -l (that is, lowercase L at the end) which disks are there.

wim@aa0:~$ sudo fdisk -l

Disk /dev/sda: 8069 MB, 8069677056 bytes
255 heads, 63 sectors/track, 981 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0003255d

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1         918     7367680   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2             918         981      509953    5  Extended
Partition 2 does not end on cylinder boundary.
/dev/sda5             918         981      509952   82  Linux swap / Solaris

Disk /dev/sdb: 4127 MB, 4127195136 bytes
127 heads, 62 sectors/track, 1023 cylinders
Units = cylinders of 7874 * 512 = 4031488 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000451df

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1        1023     4027520    b  W95 FAT32
Partition 1 has different physical/logical endings:
     phys=(1023, 126, 62) logical=(1022, 126, 62)
wim@aa0:~$

In the above, there are 2 disks, /dev/sda (my system disk) and /dev/sdb (an additional disk). You will get a few more (sdc, sdd etc, one for each disk inyour system)

Make sure the partitions on the non-system disks are not mounted.

wim@aa0:~$ mount
/dev/sda1 on / type ext4 (rw,noatime,errors=remount-ro)
tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
udev on /dev type tmpfs (rw,mode=0755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
fusectl on /sys/fs/fuse/connections type fusectl (rw)
/dev/sdb1 on /media/PENDRIVE type vfat (rw,nosuid,nodev,uhelper=hal,uid=1000,shortname=winnt)
wim@aa0:~$

In this case, partition 1 (/dev/sdb1) of disk2 (/dev/sdb) is mounted. You need to unmount all partitions of the non-system disks if they are mounted.

wim@aa0:~$ sudo umount /dev/sdb1 
wim@aa0:~$

Next you can wipe the disk by overwriting it with zeros using the dd command

sudo dd if=/dev/zero of=/dev/sdb

Repeat for sdc, sdd etc. MAke sure that you don't overwrite you system disk which is probably /dev/sda.

You can force the commands to the background by adding an ampersand at the end

sudo dd if=/dev/zero of=/dev/sdb &

Personally I would rather open multiple consoles / terminals and run each 'dd' in its own terminal so you can more easily check when they are done.

Note that the process can take long. For a normal wipe this should be enough; normal users will not be able to get data back that is wiped that way. I'm not that paranoid that I will overwrite with /dev/random and do multiple wipes so I will use /dev/zero.

One link that I found:
http://how-to.wikia.com/wiki/How_to_...clean_in_Linux

Note:
commands in red bold

[Grenage]

As an addition to the excellent advice already received, assuming that you're using a server with true RAID, your drives may well show up more like:

/dev/cciss/c0d0

rather than:

/dev/sda

Merely because of the controller.

It may also be worth stipulating a large block size when using dd (4096 or so), although I'm not sure if that will have a great impact on a zero session.

[Cheesemill]

Just to add to Win Sturkenboom's post you can increase the speed that dd runs at by adding the bs (block size) argument:

sudo bs=4MB if=/dev/zero of=/dev/sdb

[Wim Sturkenboom]

Note:
the fact that you're using server hardware can make a difference for what you see in the fdisk output. If not sure, post the output of the first command.

//Edit
just see that Grenage already covered that.

[Wim Sturkenboom]

Just to add to Win Sturkenboom's post you can increase the speed that dd runs at by adding the bs (block size) argument:

sudo bs=4MB if=/dev/zero of=/dev/sdb

That is shown in the link that I provided. I however have a question about that (without trying to hijack the thread): what is the optimal size for the bs parameter or how to determine the optimal size?

[Grenage]

what is the optimal size for the bs parameter or how to determine the optimal size?

It's completely system-dependant, not least of course - the drives themselves. With modern drives, I imagine one could happily use 8-16M chunks, given the abundance of cache.

[Wim Sturkenboom]

It's completely system-dependant, not least of course - the drives themselves. With modern drives, I imagine one could happily use 8-16M chunks, given the abundance of cache.

I understand that I was thinking about a more scientific answer

Block size? HD buffer size? What else?

Reason for asking is that I (sorry, my system) just has spend roughly 30 hours running creating an image of a 125GB partition (bs was 1M) to (OK, I admit) an USB2 external HD.

[Grenage]

I understand that I was thinking about a more scientific answer

Block size? HD buffer size? What else?

Reason for asking is that I (sorry, my system) just has spend roughly 30 hours running creating an image of a 125GB partition (bs was 1M) to (OK, I admit) an USB2 external HD.

I'd probably push the BS to the cache size, although with USB, I don't think it's going to make much difference.

Alas, I fear we have derailed this thread some!

[dcody]

Thanks for the help - I will be back a my workstation in about 2 hours and run fdisk and post output - last time I ran it it only showed one disk - I will run it again. Thanks.