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Storage Foundation 8.0 Configuration and Upgrade Guide - AIX

Last Published: 2021-12-28

Product(s): InfoScale & Storage Foundation (8.0)

Platform: AIX

Support for AIX Live Update (Technology preview)

Veritas InfoScale supports the AIX Live Update feature. Starting with AIX Version 7.2, the AIX operating system provides the AIX Live Update feature that aims to eliminate the workload downtime that is associated with the AIX kernel update operation.

The AIX Live Update feature provides an efficient way to apply the AIX updates, ifixes, service packs, and technology levels without restarting the system. You can trigger the AIX 7.2 Live Kernel Update using the geninstall -k command that updates the OS automatically without any manual intervention or downtime. Though the I/O operations are paused for a few seconds, the critical enterprise workloads remain almost during the Live Update operation. The LKU framework recognizes if InfoScale is installed on the server and takes appropriate action while performing live updates.

Note:

If Live update operation fails due to any AIX specific error, Veritas does not guarantee sanity of machine after LKU operation is completed.

Prerequisites to use the LKU feature with InfoScale

The systems with InfoScale running on it must be LKU compatible
InfoScale is running on a platform where IBM supports LKU with InfoScale
The Technology Level to which you want to upgrade must be supported by InfoScale
LKU should not be executed with the array having 2Mb gatekeeper disk

How does Live Update work?

The Live kernel update operation gets initiated using the geninstall -k command from the original partition where the workload is currently running.
The LKU framework provisions another LPAR on-the-fly with updated kernel extensions. This partition is referred to as a surrogate partition.
The surrogate partition is patched with the updated kernel versions while the workload is still running on the original partition.
Once the surrogate partition is up and running, the workload is moved from the original partition to the surrogate partition using the checkpoint and restart mechanism.
The workload resumes on the surrogate partition in a "chrooted" environment.

When you perform an LKU operation, the geninstall command uses the lvupdate.data configuration file that is available in the /var/adm/ras/liveupdate directory. This configuration file contains the data that is required for the LKU operation. You can use the lvupdate.template file from the /var/adm/ras/liveupdate directory to create the lvupdate.data file. The template file contains the descriptions of all possible fields required for the LKU operation. The following example shows a sample lvupdate.data file:

general:
       kext_check = yes
       aix_mpio = no
 disks:
      nhdisk  = <hdisk1>
      mhdisk  = <hdisk2>
 hmc:
      lpar_id  = <lparid>
      management_console = <management console ip>
      user = <user>

When you create this configuration file, ensure that:

You set the value of aix_mpio field to no to disable the native Multi-Path I/O (MPIO).
Provide hdisk# as values for the nhdisk and mhdisk fields.
- nhdisk: The names of disks to be used to make a copy of the original rootvg which will be used to boot the Surrogate.
- mhdisk: The names of disks to be used to temporarily mirror rootvg on the Original LPAR.
The size of the specified disks must match the total size of the original rootvg.
These disks should be free. Application or Administrator should not use these disks for any other operation during the Live update operation.
These disks should not be a part of any active or disabled Logical Volume Manager (LVM) volume groups.
These disks should not be a part of any VxVM disk group and should not have any VxVM tag.

Limitations of LKU with InfoScale

Consider the following restrictions for the AIX Live Update operation with InfoScale:

LKU supports only the storage components of InfoScale
LKU is not supported in a CVM environment
LKU is not supported for setups with combined configuration of DMP and third-party driver. For example, native MPIO.
LKU does not support the following InfoScale features:
- Clustering for HA or DR
- Support for 3rd party multipathing solution
- VVR and VFR Replication
- Snapshot
- FSS
- SmartIO
- Deduplication
- Compression
- In-memory statistics handling
- Power VC
- User initiated VxVM operations during LKU
- Read-Write clones (checkpoints)
- Cluster Filesystem
- Partition Directories
InfoScale product upgrades are not supported through the LKU operation
LKU operation is not supported in high availability configurations for InfoScale
LKU operation is not supported in presence of VxVM swap devices
LKU operation is not supported if any of the administrative tasks like fsadm, fsck is running
LKU operation fails if any changes like volume creation, deletion and so on are made to the VxVM configuration within the LKU start and MCR phase
LKU operation is not supported in presence of vSCSI disk
The integration of InfoScale products and LKU framework is supported only for the Local Mount filesystem

Known issues

LKU operation fails with the "kernel extensions are not known to be safe for Live Update: vxglm.ext(vxglm.ext64)" error.

A Live Update operation fails if a loaded kernel extension is not marked as safe in the safe list.

If the Group Lock Manager (GLM) is installed on a system, but the VRTSglm package is not marked with the SYS_LUSAFE flag, the LKU operation fails with the "kernel extensions are not known to be safe for Live Update: vxglm.ext(vxglm.ext64)" error.

Workaround:

Mark the VRTSglm package SYS_LUSAFE before initiating the LKU operation.

To add the VRTSglm package to the safe list for the Live Update operation, use the following command:

# lvupdateSafeKE -a /usr/lib/drivers/vxglm.ext\(vxglm.ext64\)

LKU operation fails if the ODM file system is mounted

In the technology preview mode, LKU operation is not supported with VRTSodm.

Workaround:

Unmount the ODM file system using the umount /dev/odm command.
Initiate the LKU operation using the geninstall -k command.