This chapter includes sections on the following topics:
Table A-1 summarizes the creation of a simple XVM logical volume and a simple XLV logical volume. This example is the same example provided in “Creating a Logical Volume with a Three-Way Stripe” in Chapter 7. Refer to that section for a step-by-step explanation of the XVM logical volume creation.
The commands provided in this example create a logical volume named stripedvol in which the data is to be striped across three disks. Both of these examples assume that the disks have already been partitioned as IRIX option disks. Although the commands are presented side-by-side in the table, they do not necessarily correspond to the same action.
Table A-1. XVM and XLV Logical Volume Creation
XVM Logical Volume | XLV Logical Volume |
|---|---|
Label the disks as XVM physical volumes: xvm:cluster> label -name disk0 \ xvm:cluster> label -name disk1 \ xvm:cluster> label -name disk2 \ | Create the logical volume: xlv_make> vol stripedvol |
| Create the data subvolume: xlv_make> data |
Create XVM slices out of each disk: xvm:cluster> slice -all disk* | Create the plex: xlv_make> plex |
Create the striped volume element and attach it to the volume stripedvol (creating the data subvolume in the process): xvm: cluster> stripe -volname \ | Create the striped volume element to be striped across the three disks: xlv_make> ve -stripe dks0d2s7 \ dks0d3s7 dks5d4s7 |
Exit the XVM Volume Manager: xvm:cluster> quit | Exit the XLV Volume Manager. Since the xlv_make -A option was not used, xlv_assemble is automatically called to configure the volume into the running kernel: xlv_make> end xlv_make> exit |
Execute the mkfs command on the filesystem: # mkfs /dev/cxvm/stripedvol | Execute the mkfs command on the filesystem: # mkfs /dev/xlv/stripedvol |
Mount the filesystem. For a shared filesystem in a CXFS cluster, you mount the filesystem with the CXFS GUI or the cmgr(1M) command. For a local filesystem, you can use the mount command. | Mount the filesystem: # mount /dev/xlv/stripedvol /mnt |
Use the following procedure to convert an XLV logical volume configuration to an XVM logical volume configuration:
Save the old XLV configuration and disk partitions:
# xlv_mgr -c "script -write xlvconfig all" # prtvtoc /dev/rdsk/*vh > diskparts |
Back up existing filesystems.
Delete the XLV volumes you are converting.
To delete all volumes, unmount all XLV filesystems then execute the following commands:
# xlv_shutdown # xlv_mgr -x -c “delete all_labels” |
Do not delete all XLV volumes if you have an XLV root volume, because you cannot use an XVM volume as a root volume.
Give the XLV disks to XVM to manage by labeling them as XVM disks:
# xvm label -name xvmdisk1 dks0d1vh |
Create slices to match the old partitions used by XLV.
For the XVM -start argument, subtract the size of the volume header from the prtvtoc partition start block. In this case, if slice 7 starts at block 4096 and is adjacent to the volume header, use -start 0.
The -length argument is the prvtoc partition size.
# xvm slice -start 0 -length 17779016 xvmdisk1 |
Create concatenated or striped volumes on top of the slices. Name the volumes to match previous XLV volume names to minimize the need to change the contents of /etc/fstab.
Mount the filesystems and run xfs_check on the filesystems. If there is a problem mounting the filesystems or if there is a problem that xfs_check reveals, check the following:
Compare the slices created on each disk with the saved prtvtoc information.
Compare the organization of the stripes and concatenated volumes with the XLV information.
If you find you need to restore your XLV configuration, you can use the following procedure as long as you have not built a new configuration using the XVM Volume Manager that you cannot replicate in XLV (for example, you cannot stripe concatenated volume elements in XLV).
Unmount the filesystems:
# umount -a |
Remove the XVM volume header from all the physical volumes and restore the original partitions:
# xvm unlabel -force phys/* |
Rebuild the XLV configuration:
# xlv_make xlvconfig |
The way that mirrors are configured in XLV logical volumes increases the likelihood that two disk failures will cause the entire mirror to fail. This is because an XLV logical volume could include a mirrored stripe, but not a striped mirror. The XVM Volume Manager, on the other hand, does allow you to stripe mirrors.
The following procedure provides a safe way to convert from XLV mirrored stripes to XVM striped mirrors. In this procedure, the logical volume is named alpha and the disk names are dks18* and dks5*.
Unmount the filesystem you are converting.
Create a script to regenerate the XLV configuration for alpha in case you want to recreate it later:
# xlv_mgr -c "script -write alpha object alpha" |
Detach plex 0 from the XLV volume:
# xlv_mgr -c "detach plex alpha.data.0 alphaplex" |
Delete the object. If other XLV volumes exist on this disk, generate a script to regenerate the volumes as they will also need to be converted:
# xlv_mgr -c "delete object alphaplex" |
Call up the XVM Volume Manager and label the plex0 disks:
xvm:local> label dks18* |
In this example, the filesystem has a single slice per disk. Create an XVM slice on each of the disks, consisting of the entire disk:
xvm:local> slice -all dks18* |
Create a stripe to match the XLV configuration:
xvm:local> stripe -volname alpha slice/dks18* |
Leave the XVM Volume Manager and verify that the filesystem mounts correctly:
# mount /dev/lxvm/alpha /mountpoint |
The data is now available through the XVM Volume Manager, but is not mirrored. Note the topology of the volume alpha:
xvm:local> show -t alpha
vol/alpha 0 online
subvol/alpha/data 106664448 online,open
stripe/stripe0 106664448 online,tempname,open
slice/dks18d1s0 17777424 online,open
slice/dks18d2s0 17777424 online,open
slice/dks18d3s0 17777424 online,open
slice/dks18d4s0 17777424 online,open
slice/dks18d5s0 17777424 online,open
slice/dks18d6s0 17777424 online,open
|
Insert mirrors above each of the slices in the volume alpha:
xvm:local> insert mirror slice/dks18* |
This yields the following configuration:
xvm:local> show -t alpha
vol/alpha 0 online
subvol/alpha/data 106664448 online,open
stripe/stripe0 106664448 online,tempname,open
mirror/mirror0 17777424 online,tempname
slice/dks18d1s0 17777424 online,open
mirror/mirror1 17777424 online,tempname
slice/dks18d2s0 17777424 online,open
mirror/mirror2 17777424 online,tempname
slice/dks18d3s0 17777424 online,open
mirror/mirror3 17777424 online,tempname
slice/dks18d4s0 17777424 online,open
mirror/mirror4 17777424 online,tempname
slice/dks18d5s0 17777424 online,open
mirror/mirror5 17777424 online,tempname
slice/dks18d6s0 17777424 online,open
|
Convert the other half of the XLV plex to an XVM volume and attach to the mirrors:
# xlv_mgr -c "delete object alpha" xvm:local> label dks5* xvm:local> slice -all dks5* xvm:local> attach slice/dks5d1s0 mirror0 xvm:local> attach slice/dks5d2s0 mirror1 xvm:local> attach slice/dks5d3s0 mirror2 xvm:local> attach slice/dks5d4s0 mirror3 xvm:local> attach slice/dks5d5s0 mirror4 xvm:local> attach slice/dks5d6s0 mirror5 |
Alternately, you could use the following syntax for the attach commands:
xvm:local> attach slice/dks5d1s0 stripe0/0 xvm:local> attach slice/dks5d2s0 stripe0/1 xvm:local> attach slice/dks5d3s0 stripe0/2 xvm:local> attach slice/dks5d4s0 stripe0/3 xvm:local> attach slice/dks5d5s0 stripe0/4 xvm:local> attach slice/dks5d6s0 stripe0/5 |
Show the topology of volume alpha:
xvm:local> show -t alpha
vol/alpha 0 online
subvol/alpha/data 106664448 online,open
stripe/stripe0 106664448 online,tempname,open
mirror/mirror0 17777424 online,tempname,reviving:28%,open
slice/dks18d1s0 17777424 online,open
slice/dks5d1s0 17777424 online,open
mirror/mirror1 17777424 online,tempname,reviving:queued,open
slice/dks18d2s0 17777424 online,open
slice/dks5d2s0 17777424 online,open
mirror/mirror2 17777424 online,tempname,reviving:queued,open
slice/dks18d3s0 17777424 online,open
slice/dks5d3s0 17777424 online,open
mirror/mirror3 17777424 online,tempname,reviving:queued,open
slice/dks18d4s0 17777424 online,open
slice/dks5d4s0 17777424 online,open
mirror/mirror4 17777424 online,tempname,reviving:queued,open
slice/dks18d5s0 17777424 online,open
slice/dks5d5s0 17777424 online,open
mirror/mirror5 17777424 online,tempname,reviving:queued,open
slice/dks18d6s0 17777424 online,open
slice/dks5d6s0 17777424 online,open
|
Update the /etc/fstab file entry from /dev/xlv/alpha to /dev/lxvm/alpha.