This
document describes the procedure to remove a virtual disk in a volume group on
a Virtual I/O Client, to map the virtual scsi disk to its corresponding backing
device, and to remove the backing device from the Virtual I/O Server. Please, read the entire document before
proceeding.
This
document applies to AIX version 5.3 and above.
In
a Virtual I/O environment, the physical devices are allocated to the VIO
server. When there is a hardware failure
(disk or adapter may go bad) on the VIO server, unless the VIO server has some
type of redundancy, that will have an impact on the VIO client whose virtual
disks are being served by the failing device.
The impact may be loss of connectivity to the virtual scsi disks, unless
there is some type of redundancy (MPIO or LVM mirroring) on the client
partition.
This
document does NOT apply to any of the following environments:
1.
If the virtual disk is in a shared volume group (i.e HACMP, etc)
2.
If the virtual disk is part of rootvg volume group.
Removing
a Physical Volume from a Volume Group
The
following steps are needed to remove a virtual disk from the VIO client, and
they are later discussed in more detail:
1.
Deallocate all the physical partitions associated with the physical volume in
the volume group.
2.
Remove the physical volume from the volume group
3.
Map the virtual scsi disk on the VIO client partiton to the backing device on
the VIO server.
4.
Remove the virtual scsi disk definition from the device configuration database.
5.
Remove the backing device.
At
this point, a new virtual scsi can be added to the VIO client in place of the
virtual disk that was removed in the case where this procedure was done as a
result of a hardware failure on the VIO server partition.
1.
Deallocating the physical partitions
In
the following procedure, we will be using hdisk4 in the example, as the virtual
scsi disk wanting to be removed from the VIO client.
First,
we need to determine the logical volumes defined on the physical volume we want
to remove. This can be done by running:
#
lspv -l hdisk#
where
hdisk# is the virtual scsi disk to be removed.
Example:
#
lspv -l hdisk4
hdisk4:
LV
NAME LPs PPs DISTRIBUTION
MOUNT POINT
fslv00 2 2 00..02..00..00..00 /test
loglv00 1 1 00..01..00..00..00 N/A
rawlv 30 30 00..30..00..00..00 N/A
If
the hdisk name no longer exists, and the disk is identifiable only by its
16-digit PVID (you might see this from the output of lsvg -p <VGname>),
substitute the PVID for the disk name. For example:
# lspv -l 00c2b06ef8a9f98a
You may receive the following error:
0516-320 : Physical volume 00c2b06ef8a9f98a is not assigned to
a
volume group.
If so,
run the following command:
#
putlvodm -p `getlvodm -v <VGname>` <PVID>
VGname refers to your
volume group, PVID refers to the 16-digit physical volume identifier,
and the characters around the getlvodm command are grave marks, the
backward single quote mark. The lspv -l <PVID> command
should now run successfully. To
determine the VGname associated with that physical volume use lspv hdisk#.
If
another disk in the volume group has space to contain the partitions on this
disk, and the virtual scsi disk to be replaced has not completely failed, the migratepv
command may be used to move the used PPs on this disk. See the man page for the
migratepv command on the steps to do this.
If the
partitions cannot be migrated, they must be removed. The output of the lspv
-l <hdisk#>, or lspv -l <PVID>, command
indicates what logical volumes will be affected. Run the following command on
each LV:
# lslv <LVname>
The COPIES field shows if the LV is mirrored.
If so, remove the failed copy with:
# rmlvcopy <LVname> 1
<hdisk#>
hdisk# refers to all the
disks in the copy that contain the failed disk. A list of drives can be
specified with a space between each. Use the lslv -m <LVname>
command to see what other disks may need to be listed in the rmlvcopy
command. If the disk PVID was previously used with the lspv command,
specify that PVID in the list of disks given to the rmlvcopy
command. The unmirrorvg command
may be used in lieu of the rmlvcopy command. See the man pages for rmlvcopy
and unmirrorvg, for additional information.
If the
logical volume is not mirrored, the entire logical volume must be removed, even
if just one physical partition resides on the drive to be replaced and cannot
be migrated to another disk. If the unmirrored logical volume is a JFS or JFS2
file system, unmount the file system and remove it. Enter:
# umount /<FSname>
# rmfs /<FSname>
If the unmirrored logical volume is a paging
space, see if it is active. Enter:
# lsps -a
If it is active, set it to be inactive on the
next reboot. Enter:
# chps -a n <LVname>
Then deactivate it and remove it remove it by
entering:
# swapoff /dev/<LVname>
# rmps <LVname>
Remove any other unmirrored logical volume
with the following command:
# rmlv <LVname>
2.
Remove the physical volume from the volume group.
In
the case where the virtual scsi disk to be replaced is the only physical volume
in the volume group, then remove the volume group, via:
#
exportvg <VGname>
This
will deallocate the physical partitions and will free up the virtual disk. Then, remove the disk definition, as noted on
step 3.
In
the case where there are more than one physical volumes. Using either the PVID or the hdisk name,
depending on which was used when running lspv -l in the preceding
discussion, run one of the following:
# reducevg <VGname>
<hdisk#>
# reducevg <VGname> <PVID>
If you used the PVID value and if the reducevg
command complains that the PVID is not in the device configuration database,
run the following command to see if the disk was indeed successfully removed:
# lsvg -p <VGname>
If the PVID or disk is not listed at this
point, then ignore the errors from the reducevg command.
3. How
to map the virtual scsi disk (on the client partiton) to the physical disk (on
the server partition)
In
the following example, we are going to determine the mapping of virtual scsi
disk, hdisk4
On
the VIO client:
The
following command shows the location of hdisk4:
#
lscfg -vl hdisk4
hdisk4 U9117.570.102B06E-V1-C7-T1-L810000000000 Virtual SCSI Disk Drive
where
V1 is the LPAR ID (in this case 1), C7 is the slot# (in this case 7), and L81
is the LUN ID.
Take
note of these values.
Next,
determine the client SCSI adapter name, by ‘grep’ing for the location of
hdisk4's parent adapter, in this case, V1-C7-T1:
#
lscfg -v|grep V1-C7-T1
vscsi4 U9117.570.102B06E-V1-C7-T1 Virtual SCSI Client Adapter
Device
Specific.(YL)........U9117.570.102B06E-V1-C7-T1
hdisk4
U9117.570.102B06E-V1-C7-T1-L810000000000
Virtual SCSI Disk Drive
where
vscsi4 is the client SCSI adapter.
On
the HMC:
Run
the following command to obtain the LPAR name associated with the LPAR ID
#
lshwres -r virtualio --rsubtype scsi -m <Managed System Name> --level
lpar
To
get the managed system name, run
#
lssyscfg -r sys -F name
Then,
look for the "lpar_id" and "slot_num" noted earlier. In our case, the VIO client lpar id is 1 and
the slot # is 7.
In
the following example, the managed system name is Ops-Kern-570. The VIO client partition name is kern1.
The
VIO Server partition name is reg33_test_vios.
#
lshwres -r virtualio --rsubtype scsi -m Ops-Kern-570 --level lpar
...
lpar_name=kern1,lpar_id=1,slot_num=7,state=1,is_required=0,adapter_type=client,
remote_lpar_id=11,remote_lpar_name=reg33_test_vios,remote_slot_num=23,backing_devices=none
...
Take
note of the remote_lpar_id (11) and the remote_slot_num (23). Then, in the same output, look for a line
that corresponds to "lpar_id 11, slot # 23
...
lpar_name=reg33_test_vios,lpar_id=11,slot_num=23,state=1,is_required=0,adapter_type=server,
remote_lpar_id=any,remote_lpar_name=,remote_slot_num=any,backing_devices=none
...
So
in this case, VIO server reg33_test_vios is serving virtual scsi disk, hdisk4,
on the VIO client, kern1.
On
the VIO Server:
Go
to the VIO Server associated with the LPAR ID obtained in the previous step, in
our case reg33_test_vios.
As
padmin, run the following command to display the mapping, which should match
the mapping obtained from the HMC obtained above.
$
lsmap -all|grep <VIO server lpar ID>-<VIOS slot#>
For
example,
$
lsmap -all|grep V11-C23
where
V11 is the VIO server lpar_id and C23 is the slot #
The
cmd will return something similar to
vhost21 U9117.570.102B06E-V11-C23 0x00000001
In
this case, vhost21 is the server SCSI adapter mapped to our VIO client lpar id
1 (0x00000001).
Next,
list the mapping for the vhost# obtained previously.
$
lsmap -vadapter vhost21
SVSA Physloc Client
Partition ID
--------------- -------------------------------------------- ------------------
vhost21 U9117.570.102B06E-V11-C23 0x00000001
VTD virdisk01
LUN 0x8100000000000000
Backing
device clientlv01
Physloc
Take
note of the VTD and Backing device name.
In this case, the backing device mapped to virtual scsi disk, hdisk4, is
logical volume, clientlv01, and it is associated with Virtual Target Device,
virdisk01.
4.
Remove the virtual scsi disk definition from the device configuration database
on the VIO client
To
remove the vscsi definition, run
#
rmdev -dl hdisk#
Ensure
you know the backing device associated with the virtual scsi disk being removed
prior to issuing the rmdev command. That
information will be needed in order to do clean up on the server
partition. Refer to the section
"How to map the virtual scsi disk (on the client partition) to the
physical disk (on the server partitions)".
5.
Remove the backing device on the VIO server
The
peripheral device types or backing devices currently supported are
· logical
volume
· physical
volume
· optical
device starting at v1.2.0.0-FP7 (but not currently supported on System i)
Prior
to removing the backing device, the virtual target device must be removed
first. To do so, run the following as padmin:
$
rmdev -dev <VTD name>
$
rmlv <LVname>
or
you can remove both the VTD and logical volume in one command by running:
$
rmvdev -vtd <VTD name> -rmlv
In
the case where the backing device is a physical volume, then, removing the
virtual target device completes this document.
If
you need to determine the physical device and volume group that the logical
volume belongs to, you can issue the following commands prior to running rmlv
or rmvdev.
$
lslv -pv <LVname> List the
physical volume that the logical volume specified resides on.
$
lslv <LVname> Shows the characteristics of the
logical volume, including the volume group name, # of mirrored copies, etc.
In
our example, the backing device is a logical volume, clientlv01, and it resides
on the physical device, hdisk3:
$
lslv -pv clientlv01
clientlv01:N/A
PV COPIES IN BAND DISTRIBUTION
hdisk3 080:000:000 100%
000:080:000:000:000
$
rmdev -dev virdisk01
virdisk01
deleted
$
rmlv clientlv01
Warning,
all data contained on logical volume clientlv01 will be destroyed.
rmlv:
Do you wish to continue? y(es) n(o)? y
rmlv:
Logical volume clientlv01 is removed.
Related
Documentation
Virtual
I/O Server Website
http://www14.software.ibm.com/webapp/set2/sas/f/vios/home.html
Relevant
Links in Documentation Tab:
http://www14.software.ibm.com/webapp/set2/sas/f/vios/documentation/home.html
·
IBM
System p Advanced POWER Virtualization Best Practices Redbook
·
IBM
System Hardware Information Center
·
VIOS
Commands Reference
