Ubuntu 10.04 LTS partitioning??

[cpjust]

Hi,
I tried both x64 and i386 ISO images of Ubuntu 10.04 LTS and in both of them, when I get to the part where you setup your partitions and I select 'manual', it shows:

Device                                Type  Mount Point Format? Size      Used
/dev/mapper/isw_dbebcchcbi_RAID5_OS
/dev/mapper/isw_dbebcchcbi_RAID_5
  /dev/mapper/isw_dbebcchcbi_RAID_51                            1MB       unknown
  /dev/mapper/isw_dbebcchcbi_RAID_52  ntfs                      107374MB  unknown
  /dev/mapper/isw_dbebcchcbi_RAID_53  ntfs                      821246MB  unknown

I recognize RAID_OS and RAID_5 as the volume names of my RAID before I changed motherboards. Ubuntu 8.10's partitioning just showed me 3 hard drives: sda, sdb, sdc.
Any idea why the partitioning programs of Ubuntu 8.10 & 10.04 show me different info?
I also don't see my current Ubuntu 8.10 ext3 & swap partitions listed in the Ubuntu 10.04 screen.
(if it matters, I had to use the 'nomodeset' boot option to get Ubuntu 10.04 to boot up)

[bernt]

Most of the time Linux just doesn't like to use RAID. You have to install onto one of the drives and then setup the array after installation. And frankly, Windows doesn't like it most of the time either, it's just that RAID drive manufacturers distribute drivers for the Windows installer so you can use the array from the get-go.

I do believe Ubuntu has improved the detection of RAID drives since 8.10 though - actually I think support for RAID really came into play in 9.10. So probably the reason Ubuntu 8.10 isn't showing sda, sdb, sdc is because it doesn't know that it's looking at a RAID drive.

If it's any help there's an article on the Ubuntu site regarding the use of RAID in 8.10.

[cpjust]

OK, this should be an easy one for you Linux experts.
How can I completely wipe my hard drives from Linux?
When I use a Ubuntu CD to boot up and go into GPartd, it shows me 3 drives /dev/sda - sdc with nothing on them, but Ubuntu 10.04 sees some RAID partitions on them. So is there some dd command or something to just wipe them all?
For some reason I can't mount them with 'mount /dev/sda /mnt' -- it just says:

mount: unknown filesystem type 'isw_raid_member'

[bernt]

Device -> Create Partition Table (In Gparted)

EDIT:

For some reason I can't mount them with 'mount /dev/sda /mnt' -- it just says:

mount: unknown filesystem type 'isw_raid_member'

If you know what the filesystem is you can mount with the -t option. From the man page:

-t vfstype
The argument following the -t is used to indicate the file system type. The file system types which are currently supported include: adfs, affs, autofs, cifs, coda, coherent, cramfs, debugfs, devpts, efs, ext, ext2, ext3, hfs, hpfs, iso9660, jfs, minix, msdos, ncpfs, nfs, nfs4, ntfs, proc, qnx4, ramfs, reiserfs, romfs, smbfs, sysv, tmpfs, udf, ufs, umsdos, usbfs, vfat, xenix, xfs, xiafs. Note that coherent, sysv and xenix are equivalent and that xenix and coherent will be removed at some point in the future -- use sysv instead. Since kernel version 2.1.21 the types ext and xiafs do not exist anymore. Earlier, usbfs was known as usbdevfs.

[cpjust]

I don't see a -t option for a isw_raid_member file system.
What if I just want to mount the raw drive regardless of what the existing file system is, just so I can wipe it clean and create a new file system on it?

[bernt]

I don't see a -t option for a isw_raid_member file system.

I meant you could mount with whatever filesystem is actually represented on that drive (ie, ext3 or ntfs) since isw_raid_member isn't actually a file system and mount is detecting it incorrectly.
So if the drive was used by Ubuntu, you'd mount with "-t ext3" and that would override the autodetect.

EDIT: Oh, I think the problem is that you're trying to mount the drive. You should be mounting the partition - so probably /dev/sda1, but you can check that with gparted.

What if I just want to mount the raw drive regardless of what the existing file system is, just so I can wipe it clean and create a new file system on it?

You don't have to mount to wipe a drive. In fact, you can't format a mounted drive since that would cause serious problems should the computer be accessing it at the time.
To make a new filesystem just delete whatever partitions are there and create new ones in their place (remember to click "apply changes" when you're ready). Or if you want to wipe the entire drive quickly you can make a new partition table.

[cyberfish]

sudo dd if=/dev/zero of=/dev/sda bs=4096

That would wipe the whole drive (NOT JUST THE PARTITION).

Probably enough to just do

sudo dd if=/dev/zero of=/dev/sda count=512

To just wipe out the MBR. It would be blank for all intents and purposes (except security).

EDIT: oh and don't mount the drive.

[MK27]

You don't have to mount to wipe a drive. In fact, you can't format a mounted drive since that would cause serious problems should the computer be accessing it at the time.

You can use fdisk to repartition the mounted drive -- the changes do not take effect until reboot.

[root~] fdisk /dev/sda

Command (m for help): m
Command action
   a   toggle a bootable flag
   b   edit bsd disklabel
   c   toggle the dos compatibility flag
   d   delete a partition
   l   list known partition types
   m   print this menu
   n   add a new partition
   o   create a new empty DOS partition table
   p   print the partition table
   q   quit without saving changes
   s   create a new empty Sun disklabel
   t   change a partition's system id
   u   change display/entry units
   v   verify the partition table
   w   write table to disk and exit
   x   extra functionality (experts only)

Command (m for help): p

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000a87b1

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1       12647   101586996   83  Linux
/dev/sda2           12648       21003    67119570   83  Linux
/dev/sda3           21004       37713   134223075   86  NTFS volume set
/dev/sda4           37714       60801   185454360    5  Extended
/dev/sda5           37714       50246   100671291   83  Linux
/dev/sda6           50247       60801    84783006   83  Linux

I could delete all of them. Then when I reboot, I would have an unusable drive with an empty partition table. Or I could delete all of them, create new ones (that will be unformated, but they are typed and ready to format) and when I use an installer, everything will already be set up how I want so it won't have to screw around. AFAIK you can't resize a partition with fdisk (you can only delete and create) but there is a how-to for that here:

http://www.howtoforge.com/linux_resi...xt3_partitions

I've said this half a dozen times here before -- always a good idea to keep a backup of your MBR, esp. when screwing with some silly new installer.

[cpjust]

I tried doing:

sudo dd if=/dev/zero of=/dev/sda bs=1M

on all 3 drives and then I read the first 1K:

sudo dd if=/dev/sda bs=1024 count=1 | hexdump

and it showed all 0's, but Ubuntu 10.04 STILL shows those RAID volumes! WTF?? Did my last motherboard somehow burn those into the hard drive firmwares or something?

[MK27]

If you can access the drive to run dd on it, why don't you use fdisk to create a partition table?

Otherwise just zero the whole drive

[bernt]

Ubuntu 10.04 STILL shows those RAID volumes!

The drives or the partitions?
It's still going to show the drive regardless of whether there's a partition on it, as long as it's connected and in working order.

Did my last motherboard somehow burn those into the hard drive firmwares or something?

I'm afraid I've never used raid but you might check your BIOS settings - some motherboards emulate raid hardware, they call it fakeraid.

[cpjust]

OK, I got rid of that RAID "virus" from my hard drive.
No amount of fdisking or dding would get rid of them, but when I reinstalled my old motherboard, went into the RAID BIOS and selected "Reset all discs to non-RAID mode", it removed whatever it did to my drives and now Linux doesn't see those /dev/mapper RAID volumes anymore.