[rhelv6-list] RHEL6 booting issue with SAN

Amrish Parikh Amrish_Parikh at symantec.com
Fri May 13 07:26:35 UTC 2011


Hi,

I am facing very weird issue on RHEL6 when SAN cable/Luns are attached.

Below is the issue summary:

1.    I have installed RHEL6 OS (when SAN cable was not attached to the system) with desktop option, system has 4 internal disks.

a.    While OS installation internal disks was showing as sdb, sdc, sdd and sde and I installed root, boot and swap on sdb

b.    After OS installation done which went up and running properly. But, now, my disk labeling changed to sda, sdb, sdc and sdd.

(some commands I fired on that live server are below)

[root at rh12 /]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/md1               29G  3.3G   25G  12% /
tmpfs                 499M  100K  499M   1% /dev/shm
/dev/sda1             2.0G   68M  1.8G   4% /boot
[root at rh12 /]# fdisk -l

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 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: 0xe008fd5e

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1         256     2048000   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2             256        4080    30720000   fd  Linux raid autodetect
/dev/sda3            4080        4717     5120000   82  Linux swap / Solaris

Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 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: 0x0006cc86

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        3825    30720000   fd  Linux raid autodetect

Disk /dev/sdc: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 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: 0x00000000

Disk /dev/sdc doesn't contain a valid partition table

Disk /dev/sdd: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 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: 0x00000000

Disk /dev/sdd doesn't contain a valid partition table

Disk /dev/md1: 31.5 GB, 31456157696 bytes
2 heads, 4 sectors/track, 7679726 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/md1 doesn't contain a valid partition table
[root at rh12 /]# cat /proc/scsi/scsi
Attached devices:
Host: scsi4 Channel: 00 Id: 00 Lun: 00
  Vendor: ATA      Model: GB0160CAABV      Rev: n/a
  Type:   Direct-Access                    ANSI  SCSI revision: 05
Host: scsi4 Channel: 00 Id: 01 Lun: 00
  Vendor: ATA      Model: GB0160CAABV      Rev: n/a
  Type:   Direct-Access                    ANSI  SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 00
  Vendor: ATA      Model: GB0160CAABV      Rev: n/a
  Type:   Direct-Access                    ANSI  SCSI revision: 05
Host: scsi5 Channel: 00 Id: 01 Lun: 00
  Vendor: ATA      Model: GB0160CAABV      Rev: n/a
  Type:   Direct-Access                    ANSI  SCSI revision: 05
Host: scsi6 Channel: 00 Id: 00 Lun: 00
  Vendor: HL-DT-ST Model: DVDRAM GSA-E10L  Rev: LE05
  Type:   CD-ROM                           ANSI  SCSI revision: 00
Host: scsi7 Channel: 00 Id: 00 Lun: 00
  Vendor: KVM      Model: vmDisk-CD        Rev: 0.01
  Type:   CD-ROM                           ANSI  SCSI revision: 00
Host: scsi8 Channel: 00 Id: 00 Lun: 00
  Vendor: KVM      Model: vmDisk           Rev: 0.01
  Type:   Direct-Access                    ANSI  SCSI revision: 00
[root at rh12 /]#



c.     I rebooted the system several times but getting the same results.. no worries as system was working properly. No issues.



2.    Now, I attached SAN cable and SAN luns to the system when system was live i.e. when it was up and running, then I fired some commands as below
(After SAN cables+Luns attached to live system but before reboot)

[root at rh12 ~]# cat /proc/scsi/scsi
Attached devices:
Host: scsi4 Channel: 00 Id: 00 Lun: 00
  Vendor: ATA      Model: GB0160CAABV      Rev: n/a
  Type:   Direct-Access                    ANSI  SCSI revision: 05
Host: scsi4 Channel: 00 Id: 01 Lun: 00
  Vendor: ATA      Model: GB0160CAABV      Rev: n/a
  Type:   Direct-Access                    ANSI  SCSI revision: 05
Host: scsi5 Channel: 00 Id: 00 Lun: 00
  Vendor: ATA      Model: GB0160CAABV      Rev: n/a
  Type:   Direct-Access                    ANSI  SCSI revision: 05
Host: scsi5 Channel: 00 Id: 01 Lun: 00
  Vendor: ATA      Model: GB0160CAABV      Rev: n/a
  Type:   Direct-Access                    ANSI  SCSI revision: 05
Host: scsi6 Channel: 00 Id: 00 Lun: 00
  Vendor: HL-DT-ST Model: DVDRAM GSA-E10L  Rev: LE05
  Type:   CD-ROM                           ANSI  SCSI revision: 00
Host: scsi7 Channel: 00 Id: 00 Lun: 00
  Vendor: KVM      Model: vmDisk-CD        Rev: 0.01
  Type:   CD-ROM                           ANSI  SCSI revision: 00
Host: scsi8 Channel: 00 Id: 00 Lun: 00
  Vendor: KVM      Model: vmDisk           Rev: 0.01
  Type:   Direct-Access                    ANSI  SCSI revision: 00
Host: scsi0 Channel: 00 Id: 00 Lun: 00
  Vendor: DGC      Model: LUNZ             Rev: 0219
  Type:   Direct-Access                    ANSI  SCSI revision: 04
Host: scsi0 Channel: 00 Id: 01 Lun: 00
  Vendor: DGC      Model: RAID 5           Rev: 0220
  Type:   Direct-Access                    ANSI  SCSI revision: 04
Host: scsi0 Channel: 00 Id: 01 Lun: 01
  Vendor: DGC      Model: RAID 5           Rev: 0220
  Type:   Direct-Access                    ANSI  SCSI revision: 04
Host: scsi0 Channel: 00 Id: 01 Lun: 02
  Vendor: DGC      Model: RAID 5           Rev: 0220
  Type:   Direct-Access                    ANSI  SCSI revision: 04
[root at rh12 ~]#
[root at rh12 ~]# fdisk -l

Disk /dev/sdc: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 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: 0x00000000

Disk /dev/sdc doesn't contain a valid partition table

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 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: 0xe008fd5e

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1         256     2048000   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2             256        4080    30720000   fd  Linux raid autodetect
/dev/sda3            4080        4717     5120000   82  Linux swap / Solaris

Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 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: 0x0006cc86

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1        3825    30720000   fd  Linux raid autodetect

Disk /dev/sdd: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 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: 0x00000000

Disk /dev/sdd doesn't contain a valid partition table

Disk /dev/md1: 31.5 GB, 31456157696 bytes
2 heads, 4 sectors/track, 7679726 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/md1 doesn't contain a valid partition table

Disk /dev/sdg: 16.1 GB, 16106127360 bytes
64 heads, 32 sectors/track, 15360 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdg doesn't contain a valid partition table

Disk /dev/sdh: 16.1 GB, 16106127360 bytes
64 heads, 32 sectors/track, 15360 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdh doesn't contain a valid partition table

Disk /dev/sdi: 16.1 GB, 16106127360 bytes
64 heads, 32 sectors/track, 15360 cylinders
Units = cylinders of 2048 * 512 = 1048576 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000

Disk /dev/sdi doesn't contain a valid partition table
[root at rh12 ~]# cat /proc/partitions
major minor  #blocks  name

   8       32  156290904 sdc
   8        0  156290904 sda
   8        1    2048000 sda1
   8        2   30720000 sda2
   8        3    5120000 sda3
   8       16  156290904 sdb
   8       17   30720000 sdb1
   8       48  156290904 sdd
   9        1   30718904 md1
   8       96   15728640 sdg
   8      112   15728640 sdh
   8      128   15728640 sdi

[root at rh12 ~]# lsscsi
[0:0:0:0]    disk    DGC      LUNZ             0219  /dev/sdf
[0:0:1:0]    disk    DGC      RAID 5           0220  /dev/sdg
[0:0:1:1]    disk    DGC      RAID 5           0220  /dev/sdh
[0:0:1:2]    disk    DGC      RAID 5           0220  /dev/sdi
[4:0:0:0]    disk    ATA      GB0160CAABV      n/a   /dev/sda
[4:0:1:0]    disk    ATA      GB0160CAABV      n/a   /dev/sdb
[5:0:0:0]    disk    ATA      GB0160CAABV      n/a   /dev/sdc
[5:0:1:0]    disk    ATA      GB0160CAABV      n/a   /dev/sdd
[6:0:0:0]    cd/dvd  HL-DT-ST DVDRAM GSA-E10L  LE05  /dev/sr0
[7:0:0:0]    cd/dvd  KVM      vmDisk-CD        0.01  /dev/sr1
[8:0:0:0]    disk    KVM      vmDisk           0.01  /dev/sde



3.    Then, I rebooted the system and for my surprise, it was not booting up and throwing error message "No root device found, Boot has failed, sleeping forever"

a.    Reason i guess is that, system tries to boot from SAN disk instead of internal disk and fails to boot

b.    I have checked in the BIOS setting that first boot priority is set to Internal disk and not SAN disk.


4.    When I removed the SAN cable from the system, it again boots up properly. No issues found.

Can anyone let me know the solutions for that and any reason why this is happening?

Thanks in Advance!!!!

Thanks,
Amrish Parikh
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