On Thu, 6 Jul 2006, itayf@xxxxxxxxxxxxxx wrote:
Date: Thu, 6 Jul 2006 15:36:06 +0300 (IDT)
From: itayf@xxxxxxxxxxxxxx
Also, I just started working with lvm. The following warnings are genertated
whenever I run one of lvm commands on the external usb disk (MyBook by
Western Digital).
<quote>
[root@frodo pilpel10]# vgcreate VGe1 /dev/sdc2
/dev/dm-11: read failed after 0 of 4096 at 5242814464: Input/output error
/dev/dm-11: read failed after 0 of 4096 at 0: Input/output error
[snip]
Volume group "VGe1" successfully created
[root@frodo pilpel10]# pvscan
/dev/dm-11: read failed after 0 of 4096 at 5242814464: Input/output error
/dev/dm-11: read failed after 0 of 4096 at 0: Input/output error
[snip]
Total: 2 [528.91 GB] / in use: 2 [528.91 GB] / in no VG: 0 [0 ]
[root@frodo pilpel10]# lvcreate -L 202G -n LVbiogateBAK_home VGe1
/dev/dm-11: read failed after 0 of 4096 at 0: Input/output error
/dev/dm-12: read failed after 0 of 4096 at 0: Input/output error
/dev/dm-13: read failed after 0 of 4096 at 0: Input/output error
/dev/dm-14: read failed after 0 of 4096 at 0: Input/output error
Logical volume "LVbiogateBAK_home" created
</quote>
The original sin was creating the physical, group, and logical
volumes in a partition whose file system descriptor was Linux
(Id=83) and not Linux LVM (Id=8e), the '/dev/sdc2' line below.
The (undocumented) behavior of 'parted DEVICE mkpart ...' is to
create an ex2 fs if non is specified.
The confusing part for me was, that most of lvm operations were
executed, and I was able to create on the LVs a seemingly-healthy
file system (see above).
Anyway, the solution was to change the fs ID, and (to be on the
safe side) recreate the physical, group, and logical volumes.
Below is a summary of my actions.
Huge thanks to Bill Maltby for all the help and education, and to
Matt Hyclak for his short and crucial comment.
Itay
# Hard drive state before fix
[root@frodo ~]# sfdisk -l /dev/sdc
Disk /dev/sdc: 38913 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes,
counting from 0
Device Boot Start End #cyls #blocks Id System
/dev/sdc1 * 0+ 254 255- 2048256 c W95 FAT32 (LBA)
/dev/sdc2 255 38912 38658 310520385 83 Linux
/dev/sdc3 0 - 0 0 0 Empty
/dev/sdc4 0 - 0 0 0 Empty
# Is partition size OK?
[root@frodo ~]# dd if=/dev/sdc2 of=/dev/null
12747056+0 records in
12747056+0 records out
# As an extra safety, anticipate the next command's arguments
[root@frodo ~]# sfdisk --print-id /dev/sdc 2
83
# Now change the partition's file-system descriptor to Linux LVM
[root@frodo ~]# sfdisk --change-id /dev/sdc 2 8e
Done
# Reread partitions on the fly
[root@frodo ~]# sfdisk -R /dev/sdc
BLKRRPART: Device or resource busy
This disk is currently in use.
...
# Hmmmm... Reboot and relist partitions.
# The harddrive is usb so its identifier changed from c to b.
# Note the '/dev/sdb2/' line -- its Linux LVM -- and compare to
# '/dev/sdc2' above.
[root@frodo ~]# sfdisk -l /dev/sdb
Disk /dev/sdb: 38913 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes,
counting from 0
Device Boot Start End #cyls #blocks Id System
/dev/sdb1 * 0+ 254 255- 2048256 c W95 FAT32 (LBA)
/dev/sdb2 255 38912 38658 310520385 8e Linux LVM
/dev/sdb3 0 - 0 0 0 Empty
/dev/sdb4 0 - 0 0 0 Empty
# From here, [pv|gv|lv]create, and other lvm operations went
# smoothly, with no warnings.
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