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I uploaded a centos 6.2 VMDK to s3 and then converted it to volume using ec2 import volume. Then i took the snapshot of the volume and deleted it.Now I am trying to create a instance from the snapshot and keep getting following error:

"Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(8,1)"

Even i dont know which AKI to use while restoring the snapshot...Currently i am trying to restore using default values.

Full system log is as follows:

Linux version 2.6.16-xenU (root@ip-10-204-118-8) (gcc version 4.0.2 20051125 (Red Hat 4.0.2-8)) #14 SMP Wed Nov 23 08:48:06 EST 2011

BIOS-provided physical RAM map:

Xen: 0000000000000000 - 0000000026f00000 (usable)

0MB HIGHMEM available.

623MB LOWMEM available.

NX (Execute Disable) protection: active

Built 1 zonelists

Kernel command line: root=/dev/sda1 ro 4

Enabling fast FPU save and restore... done.

Enabling unmasked SIMD FPU exception support... done.

Initializing CPU#0

PID hash table entries: 4096 (order: 12, 65536 bytes)

Xen reported: 1795.672 MHz processor.

Console: colour dummy device 80x25

Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)

Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)

Software IO TLB disabled

vmalloc area: e7800000-f53fe000, maxmem 2d7fe000

Memory: 618496k/637952k available (1970k kernel code, 11016k reserved, 628k data, 156k init, 0k highmem)

Checking if this processor honours the WP bit even in supervisor mode... Ok.

Calibrating delay using timer specific routine.. 3593.73 BogoMIPS (lpj=17968651)

Mount-cache hash table entries: 512

CPU: L1 I cache: 32K, L1 D cache: 32K

CPU: L2 cache: 256K

CPU: L3 cache: 20480K

Checking 'hlt' instruction... OK.

Brought up 1 CPUs


Grant table initialized

NET: Registered protocol family 16

Brought up 1 CPUs

xen_mem: Initialising balloon driver.

VFS: Disk quotas dquot_6.5.1

Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)

Initializing Cryptographic API

io scheduler noop registered

io scheduler anticipatory registered (default)

io scheduler deadline registered

io scheduler cfq registered

i8042.c: No controller found.

RAMDISK driver initialized: 16 RAM disks of 4096K size 1024 blocksize

Xen virtual console successfully installed as tty1

Event-channel device installed.

netfront: Initialising virtual ethernet driver.

mice: PS/2 mouse device common for all mice

md: md driver 0.90.3 MAX_MD_DEVS=256, MD_SB_DISKS=27

md: bitmap version 4.39

NET: Registered protocol family 2

IP route cache hash table entries: 32768 (order: 5, 131072 bytes)

TCP established hash table entries: 131072 (order: 8, 1048576 bytes)

TCP bind hash table entries: 65536 (order: 7, 524288 bytes)

TCP: Hash tables configured (established 131072 bind 65536)

TCP reno registered

TCP bic registered

NET: Registered protocol family 1

NET: Registered protocol family 17

NET: Registered protocol family 15

Using IPI No-Shortcut mode

netfront: device eth0 has copying receive path.

Registering block device major 8

XENBUS: Device with no driver: device/console/0

md: Autodetecting RAID arrays.

md: autorun ...

md: ... autorun DONE.

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(8,1)

Please help me...struggling to fix this from last 4 days.

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up vote 1 down vote accepted

I was receiving this error because of selecting the wrong AKI id while launching the instance. As soon as i selected the correct id, this error disappeared and instance started working fine.

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