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Oracle VM: Directory Is Missing After DomU/Guest VM Restart (Doc ID 2452828.1)

Last updated on MARCH 05, 2025

Applies to:

Oracle VM - Version 3.2.6 to 3.4.5 [Release OVM32 to OVM34]
Linux x86-64

Symptoms

On a OVM  Oracle Linux guest VM with Oracle Database,  directory /u02 mount point was reportedly missing after the DomU/Guest VM restart.

Further details are found in the following:

/var/log/messages:

Before reboot: <<< The "xvdz" Virtual Disk still present before the DomU/Guest VM system reboot.

Sep  1 21:28:37 localhost kernel: blkfront: xvdz: flush diskcache: enabled; persistent grants: enabled; indirect descriptors: enabled;
Sep  1 21:28:37 localhost kernel: xvdz: xvdz1
Sep  1 21:28:37 localhost kernel: xvdz: detected capacity change from 0 to 800020496384
Sep  1 21:28:37 localhost kernel: EXT4-fs (xvdz1): mounted filesystem with ordered data mode. Opts: (null)

After reboot: <<< The "xvdz" Virtual Disk has gone missing after the DomU/Guest VM system reboot.

Sep 11 09:31:13 localhost kernel: blkfront: xvda: flush diskcache: enabled; persistent grants: enabled; indirect descriptors: enabled;
Sep 11 09:31:13 localhost kernel: xvda: xvda1 xvda2
Sep 11 09:31:13 localhost kernel: blkfront: xvdb: flush diskcache: enabled; persistent grants: enabled; indirect descriptors: enabled;
Sep 11 09:31:13 localhost kernel: xvdb: xvdb1
Sep 11 09:31:13 localhost kernel: Setting capacity to 1803550720
Sep 11 09:31:13 localhost kernel: xvdb: detected capacity change from 0 to 923417968640
Sep 11 09:31:13 localhost kernel: blkfront: xvdc: flush diskcache: enabled; persistent grants: enabled; indirect descriptors: enabled;
Sep 11 09:31:13 localhost kernel: xvdc: xvdc1
Sep 11 09:31:13 localhost kernel: blkfront: xvdd: flush diskcache: enabled; persistent grants: enabled; indirect descriptors: enabled;
Sep 11 09:31:13 localhost kernel: xvdd: xvdd1
Sep 11 09:31:13 localhost kernel: Setting capacity to 104857600
Sep 11 09:31:13 localhost kernel: xvdc: detected capacity change from 0 to 53687091200
Sep 11 09:31:13 localhost kernel: Setting capacity to 41943040
Sep 11 09:31:13 localhost kernel: xvdd: detected capacity change from 0 to 21474836480

NOTE: The xvdz Virtual Disk was present prior to reboot.

-- vm.cfg
kernel = '/usr/lib/xen/boot/hvmloader'
vif = ['mac=00:xx:xx:xx:xx:xx,bridge=acxxxxxx']
OVM_simple_name = 'localhost'
vnclisten = '127.0.0.1'
vncconsole = 1
cpuid = ['1:edx=xxxxxxxxxxxxxxxxxxx0xxxxxxxxxxxx']
serial = 'pty'
disk = ['file:/OVS/Repositories/0004fb0000030000738973812f60c895/VirtualDisks/0004fb000012000043a259af819de27b.img,xvda,w', 'file:/OVS/Repositories/0004fb00000300008f25e8d02710401f/VirtualDisks/0004fb00001200003dcfcde86ff82ae0.img,xvdb,w', 'file:/OVS/Repositories/0004fb00000300008f25e8d02710401f/VirtualDisks/0004fb0000120000ce38ac0cb6f82ca6.img,xvdc,w', 'file:/OVS/Repositories/0004fb0000030000738973812f60c895/VirtualDisks/0004fb0000120000387f2b91d17eff15.img,xvdd,w']

NOTE: The xvdz Virtual Disk has gone missing from the disk entry of the vm.cfg file.

[root@localhost~]# lsblk
NAME                           MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
xvda                           202:0    0   10G  0 disk
|-xvda1                        202:1    0  250M  0 part /boot
`-xvda2                        202:2    0  9.8G  0 part
 |-VolGroup00-LogVol01 (dm-0) 252:0    0    1G  0 lvm  [SWAP]
 |-VolGroup00-LogVol00 (dm-1) 252:1    0   55G  0 lvm  /
 `-VolGroup00-LogVol02 (dm-3) 252:3    0  100M  0 lvm  /shared_agent_instance_h
xvdb                           202:16   0  860G  0 disk
`-xvdb1                        202:17   0  860G  0 part
 `-VolGroup01-LogVol00 (dm-2) 252:2    0  860G  0 lvm  /u01  
xvdc                           202:32   0   50G  0 disk
`-xvdc1                        202:33   0 46.6G  0 part
 |-VolGroup00-LogVol00 (dm-1) 252:1    0   55G  0 lvm  /
 `-VolGroup00-LogVol03 (dm-4) 252:4    0   20G  0 lvm  [SWAP]
xvdd                           202:48   0   20G  0 disk
`-xvdd1                        202:49   0   20G  0 part
 `-VolGroup00-LogVol03 (dm-4) 252:4    0   20G  0 lvm  [SWAP]
 

NOTE: The xvdz is missing in the in the output of lsblk.

 

Checked the DomU/Guest VM /etc/fstab:

# cat /etc/fstab

# /etc/fstab
# Created by anaconda on Thu Feb 20 07:31:04 2014
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/VolGroup00-LogVol00 /                       ext4    defaults        1 1
UUID=af2bcd62-9c72-4c19-898c-12097371bed7 /boot                   ext4    defaults        1 2
/dev/mapper/VolGroup00-LogVol01 swap                    swap    defaults        0 0
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/dev/mapper/VolGroup00-LogVol02 /shared_agent_instance_home ext4    defaults 1 1
/dev/VolGroup00/LogVol00 /                              ext3  defaults 1 1
/dev/VolGroup00/LogVol03 swap                    swap    defaults        0 0
/dev/VolGroup01/LogVol00 /u01 ext4 defaults 0 0
/dev/xvdz1 /u02 ext4 defaults 0 0  

NOTE: The Virtual Disk Partition /dev/xvdz1 has found as the mount point of /u02 from the DomU/Guest VM /etc/fstab entry, but has gone missing from the VM configuration file (vm.cfg).

 

Cause

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In this Document
Symptoms
Cause
Solution


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