Host to guest disk mapping in HP iVM

disk mapping

Learn how to identify virtual machine disk on physical host machine in HP iVM. Disk mapping makes it easy to carry out disk related activities.

 


In HP integrity virtual machines, disk names on host machine and virtual machines are always different for same disk. Whenever we are presenting disk (storage LUN or local disk) from host to guest, it will be discovered as different name on guest than host. So it becomes necessary to know both names of same disk for any disk related activities.

Let see how we can map these two names. There are two methods to do this.

  1. Using xD command
  2. With hpvmdevinfo command

Using xD command:

xD command used to read raw data on disk. Since physical disk is same on both servers only identification at kernel level differs, we will get same raw data from both servers. We will use xD command to get PVID of disks from host and guest. Whenever there is a match of PVID in both outputs, consider the disk is same.

See below example where xD command is used with host and guest disks.

Now, if you observe outputs (2nd field), guest disk disk76 has same value as host disk disk532. That means its same disk! So on host diusk532 is same as disk76 on guest. Same with disk538-disk74 & disk 523-disk72.

Read also : LVM cheatsheet

This is bit of tedious job to observe outputs and find a match if you has huge number of disks. Also, if you are interested in only one VM’s data then its time consuming since you have to match all disks of host with that VM’s disks. In that case we have hpvmdevinfo command which directly prints out mapping table for you.


With hpvmdevinfo command:

This command comes with HP iVM setup and shows device mappings from host to guest in tabular format. Since this command can be run against particular VM, its pretty fast to get disk mapping than previous method.

You need to run this command by supplying VM name with -P option and you will be presented with device list, its ctd and disk mapping between host-guest servers.

In above example, see last two column where first one shows disk name on host machine and last one shows guest/virtual machine. Pretty straight forward and fast!

Any thoughts?