HP-UX vPars and Integrity VM V6.3 Administrator Guide

12.3.4 VM requirements and setup
Online VM Migration is supported on HP-UX 11i v2 and HP-UX 11i v3 guests. All memory sizes
and virtual CPU configurations for the current version of Integrity VM are supported. As with all
guest OS installations, the guest kit must be installed.
NOTE: With Integrity VM V6.3, if VirtualBase B.06.30 is installed on the guest, the guest kit
need not be installed.
12.3.4.1 Setting online migration phase time-out values
To protect the workload of the guest, the online migration software limits the amount of time spent
in each migration phase. The phases of an online migration are:
• Initialization phase—Establishes connections, carries out various checks, starts the target guest.
• Copy phase—Tracks writes to guest memory and copies all of guest memory.
• I/O quiesce phase—Queues new I/O requests and waits for outstanding I/O to complete.
• Frozen phase—Stops the virtual CPUs and copies modified memory and guest state.
For example, if a guest stops I/O to storage for long, it can experience I/O errors and applications
can fail or the operating system can crash. If a guest is frozen for long, external network connections
to the guest can time out and network connections can be dropped.
Network time-outs are troublesome for certain UDP applications that are not resilient enough to
tolerate packets being delayed and dropped. If you run UDP applications that assume fast network
packet turnaround, you must reduce the frozen phase time-out value, which might cause online
migrations to abort more often. However, it will preserve the integrity of the network connections
to the guest. The trade-off is that your migration might abort if conditions are not appropriate for
fast and efficient migrations.
If necessary, you can adjust the following migration time outs with the hpvmmodify -x command:
• migrate_init_phase_timeout—Specifies the maximum number of seconds the online migration
spends during the initial phase of the migration. The default is 90 seconds.
• migrate_copy_phase_timeout—Specifies the maximum number of seconds the online migration
spends during the full-copy phase. The default is infinite.
• migrate_io_quiesce_phase_timeout—Specifies the maximum number of seconds the migration
spends during the quiesce phase. The default is 15 seconds.
• migrate_frozen_phase_timeout—Specifies the maximum number of seconds the migration
spends during the freezing phase. The default is 60 seconds.
12.3.4.2 Migrations might time out and must be restarted
To protect a workload of the guest, the OVMM feature has limits for the amount of time that a
migrating guest can remain in various phases of a migration. There are several capacity and
resource-related reasons an attempted online migration might time out and abort, leaving the guest
running on the source host. Potential causes include:
• Insufficient resources on the target host
• Excessively busy VSPs
• A slow network connection
• An extremely busy guest
If such conditions exist, the attempted migration is aborted, so the workload of the guest can
continue running on the source VSP. This is not a serious problem, because the guest continues to
run on the source, and you can re-attempt the migration when conditions improve.
212 Migrating VMs and vPars