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Ive been using some of the guides on the net and have a strange problem. Ive got 4 partitions setup on the first drive sda1 sda2 sda3 and sda4 and i can see a sdb1 sdb2 and sdb3 there which im guessing is from what was previously on the drive.

My problem is all the guides i see in setting up a new hard drive talk about running fdisk against sda or sdb which should be the raw device.

My problem is these devices /dev/sda or /dev/sdb dont exist. Running fdisk -l also returns nothing.

Can anyone point me in the right direction.

Thanks in advance

Command line: BOOT_IMAGE=/boot/bzImage-3.2.13-xxxx-grs-ipv6-64 root=/dev/sda1 ro
Kernel command line: BOOT_IMAGE=/boot/bzImage-3.2.13-xxxx-grs-ipv6-64 root=/dev/sda1 ro
sd 0:0:0:0: [sda] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB)
sd 0:0:0:0: Attached scsi generic sg0 type 0
sd 1:0:0:0: [sdb] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB)
sd 1:0:0:0: [sdb] 4096-byte physical blocks
sd 1:0:0:0: [sdb] Write Protect is off
sd 1:0:0:0: [sdb] Mode Sense: 00 3a 00 00
sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
sd 1:0:0:0: Attached scsi generic sg1 type 0
sd 0:0:0:0: [sda] 4096-byte physical blocks
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
libceph: loaded (mon/osd proto 15/24, osdmap 5/6 5/6)
sda: sda1 sda2 sda3 sda4
sd 0:0:0:0: [sda] Attached SCSI disk
sdb: sdb1 sdb2 sdb3
sd 1:0:0:0: [sdb] Attached SCSI disk
md: invalid raid superblock magic on sdb1
md: sdb1 does not have a valid v0.90 superblock, not importing!
md: invalid raid superblock magic on sdb2
md: sdb2 does not have a valid v0.90 superblock, not importing!
EXT3-fs (sda1): error: couldn't mount because of unsupported optional features (240)
EXT2-fs (sda1): error: couldn't mount because of unsupported optional features (240)
EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: (null)
EXT4-fs (sda1): re-mounted. Opts: errors=remount-ro
Adding 1047548k swap on /dev/sda4.  Priority:-1 extents:1 across:1047548k
EXT4-fs (sda2): mounted filesystem with ordered data mode. Opts: (null)
EXT4-fs (sda3): mounted filesystem with ordered data mode. Opts: (null)
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When you say the devices "don't exist", what precisely do you mean? What is the output of dmesg | grep sd? –  David Schwartz Dec 23 '12 at 3:33
    
Hi there thanks for your response. the device /dev/sda or /dev/sdb dont exist on the filesystem is what i meant –  user150725 Dec 23 '12 at 3:36
    
You mean if you do ls -l /dev/sda you get "No such file or directory"? –  David Schwartz Dec 23 '12 at 3:38
    
yeah, but the drive its booting from must be sda and the sda1, sda2, sda3 and sda4 represent the partitions that were created –  user150725 Dec 23 '12 at 3:40
    
The dmesg log is detecting 2 devices, sda and sdb. It looks like they're associated to some RAID (md). Can you try a different partitioning tool such as parted? Use the command parted /dev/sdb for example. –  slm Dec 23 '12 at 4:18

2 Answers 2

After about a half days googling i think ive figured it out. You can recreate the device nodes. Once i recreated the /dev/sda, and /dev/sdb everything came right. fdisk -l worked and i was able to setup the partitions and mount points as i wanted

The webpage i followed to recreate the device nodes is below http://geekyschmidt.com/2011/03/12/why-is-my-devsda-missing

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Type this command:

sudo /dev/MAKEDEV sd

This will run the MAKEDEV program and tell it to re-create the missing /dev/sd* device files.

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Thanks tried running that but it says no such file or directory –  user150725 Dec 23 '12 at 3:47
    
I ran MAKEDEV sd without the /dev on front and it seemed to run successfully but still no sda or sdb under dev –  user150725 Dec 23 '12 at 3:50

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