Veritas InfoScale™ 8.0.2 Solutions Guide - AIX
- Section I. Introducing Veritas InfoScale
- Section II. Solutions for Veritas InfoScale products
- Section III. Stack-level migration to IPv6 or dual stack
- Section IV. Improving database performance
- Overview of database accelerators
- Improving database performance with Veritas Quick I/O
- About Quick I/O
- Improving database performance with Veritas Cached Quick I/O
- Improving database performance with Veritas Concurrent I/O
- Section V. Using point-in-time copies
- Understanding point-in-time copy methods
- Backing up and recovering
- Preserving multiple point-in-time copies
- Online database backups
- Backing up on an off-host cluster file system
- Database recovery using Storage Checkpoints
- Backing up and recovering in a NetBackup environment
- Off-host processing
- Creating and refreshing test environments
- Creating point-in-time copies of files
- Section VI. Maximizing storage utilization
- Optimizing storage tiering with SmartTier
- Optimizing storage with Flexible Storage Sharing
- Optimizing storage tiering with SmartTier
- Section VII. Migrating data
- Understanding data migration
- Offline migration of native volumes and file systems to VxVM and VxFS
- Converting LVM volume groups to VxVM disk groups
- Conversion of JFS and JFS2 file systems to VxFS
- Conversion steps explained
- Examples of using vxconvert
- About test cases
- Converting LVM, JFS and JFS2 to VxVM and VxFS
- Online migration of native LVM volumes to VxVM volumes
- Online migration from LVM volumes in standalone environment to VxVM volumes
- Online migration from LVM volumes in VCS HA environment to VxVM volumes
- Online migration of a native file system to the VxFS file system
- Migrating a source file system to the VxFS file system over NFS v3
- VxFS features not available during online migration
- Migrating storage arrays
- Migrating data between platforms
- Overview of the Cross-Platform Data Sharing (CDS) feature
- CDS disk format and disk groups
- Setting up your system to use Cross-platform Data Sharing (CDS)
- Maintaining your system
- Disk tasks
- Disk group tasks
- Displaying information
- File system considerations
- Specifying the migration target
- Using the fscdsadm command
- Maintaining the list of target operating systems
- Migrating a file system on an ongoing basis
- Converting the byte order of a file system
- Section VIII. Veritas InfoScale 4K sector device support solution
Volume group conversion limitations
There are certain LVM volume configurations that cannot be converted to VxVM. Some of the reasons a conversion could fail are:
A volume group with insufficient space for metadata.
In the conversion of LVM to VxVM, the areas of the disks used to store LVM metadata are overwritten with VxVM metadata. If the VxVM metadata that needs to be written will not fit the space occupied by the LVM metadata, the group containing the disk cannot be converted. If you have just enough space for the conversion, you probably would want to have more space for future configuration changes.
A volume group containing the root volume.
The current release of VxVM on AIX does not support VxVM root volumes. Because of this, vxconvert does not convert any volume group that contains a rootable volume. Not only is the current root volume off limits, but any volume that might be used as an alternate root volume is rejected as well.
A volume group containing mirrors using the Mirror Write Cache feature for volume consistency recovery.
You should be aware that when converting mirrored LVM volumes to VxVM, some of these volumes will likely have the Mirror Write Cache consistency recovery method in force on the volume. The vxconvert utility can convert these volumes, but in some cases, it might not be able to create an equivalent level of consistency. Therefore, vxconvert will detect this case and warn the user that converting this volume group would lose this MWC functionality and leave the resultant VxVM mirrored disk group operating in a comparatively degraded state.
Volume groups with any dump or primary swap volumes.
Because VxVM does not support rootability, vxconvert will not convert primary swap or paging space on any type of volume to VxVM.
A volume group containing the /usr file system.
For this release, a volume group containing the /usr file system cannot be converted because vxconvert needs access to files in /usr.
Volume groups with any disks that have bad blocks in the bad block directory.
Unlike LVM, VxVM does not support bad block revectoring at the physical volume level. If there appear to be any valid bad blocks in the bad block directory of any disk used in an LVM volume group, the group cannot be converted.
The list of conversion error messages describe the actions to take in this situation.
Not enough disk space on the root LVM volume group to save a copy of each physical disks VGRA area.
For large LVM volume groups, especially those with large VGDA sizes, the required space could be greater than 64MB per physical volume. So, for a Volume Group with 128 disks, the required storage space could be greater than 8 GB.
The default save area is /etc/vx/reconfig.d.
Volume groups with mirrored volumes.
A conversion fails if the LVM volume group being converted has mirrored volumes, but the system does not have a valid license installed that enables mirroring for VxVM.