InfoScale™ 9.0 Solutions Guide - Linux
- Section I. Introducing Veritas InfoScale
- Section II. Solutions for Veritas InfoScale products
- Solutions for Veritas InfoScale products
- 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 Concurrent I/O
- Improving database performance with atomic write 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 from LVM to VxVM
- Offline conversion of native file system to VxFS
- Online migration of a native file system to the VxFS file system
- Migrating a source file system to the VxFS file system over NFS v4
- 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
- Migrating from Oracle ASM to Veritas File System
- Section VIII. Veritas InfoScale 4K sector device support solution
- Section IX. REST API support
- Support for configurations and operations using REST APIs
- Support for configurations and operations using REST APIs
- Section X. Reference
Converting LVM volume groups to VxVM disk groups
To convert LVM volume groups to VxVM disk groups
- Identify the LVM disks and volume groups that are to be converted. Use LVM administrative utilities such as vgdisplay to identify the candidate LVM volume groups and the disks that comprise them. You can also use the listvg operation in vxvmconvert to examine groups and their member disks, and the list operation to display the disks known to the system as shown here:
# vxvmconvert . . . Select an operation to perform: list . . . Enter disk device or "all"[<address>,all,q,?](default: all) all DEVICE DISK GROUP STATUS cciss/c0d0 - - online invalid cciss/c0d1 - - online sda - - online sdb disk01 rootdg online sdc disk02 rootdg online sdd disk03 rootdg online sde - - error sdf - - error sdg - - error sdh - - error Device to list in detail [<address>,none,q,?] (default: none)
The DEVICE column shows the disk access names of the physical disks. If a disk has a disk media name entry in the DISK column, it is under VM control, and the GROUP column indicates its membership of a disk group. The STATUS column shows the availability of the disk to VxVM. LVM disks are displayed in the error state as they are unusable by VxVM.
To list LVM volume group information, use the listvg operation:
Select an operation to perform: listvg . . . Enter Volume Group (i.e.- vg04) or "all" [<address>,all,q,?] (default: all) all LVM VOLUME GROUP INFORMATION Name Type Physical Volumes vg02 Non-Root /dev/sdf /dev/sdh1 Volume Group to list in detail [<address>,none,q,?] (default: none) vg02 --- Volume group --- VG Name vg02 VG Access read/write VG Status available/resizable VG # 0 MAX LV 256 Cur LV 0 Open LV 0 MAX LV Size 255.99 GB Max PV 256 Cur PV 2 Act PV 2 VG Size 16.95 GB PE Size 4 MB Total PE 4338 Alloc PE / Size 0 / 0 Free PE / Size 4338 / 16.95 GB VG UUID IxlERp-poi2-GO2D-od2b-G7fd-3zjX-PYycMn --- No logical volumes defined in "vg02" --- --- Physical volumes --- PV Name (#) /dev/sdf (2) PV Status available / allocatable Total PE / Free PE 2169 / 2169 PV Name (#) /dev/sdh1 (1) PV Status available / allocatable Total PE / Free PE 2169 / 2169 List another LVM Volume Group? [y,n,q,?] (default: n)
- Plan for the new VxVM logical volume names. Conversion changes the device names by which your system accesses data in the volumes. LVM creates device nodes for its logical volumes in /dev under directories named for the volume group. VxVM create device nodes in
/dev/vx/dsk/diskgroup
and/dev/vx/rdsk/diskgroup
. After conversion is complete, the LVM device nodes no longer exist on the system.For file systems listed in
/etc/fstab
, vxvmconvert substitutes the new VxVM device names for the old LVM volume names, to prevent problems with fsck, mount, and other such utilities. However, other applications that refer to specific device node names may fail if the device no longer exists in the same place.Examine the following types of application to see if they reference LVM device names, and are at risk:
Databases that access raw logical devices.
Backups that are performed on device nodes named in private files. Labeling of backups may also record device names.
Scripts run by cron.
Other administrative scripts.
- Select item 1 Analyze LVM Volume Groups for Conversion from the vxvmconvert main menu to see if conversion of each LVM volume group is possible.
This step is optional. Analysis can be run on a live system while users are accessing their data. This is useful when you have a large number of groups and disks for conversion to allow for the optimal planning and management of conversion downtime.
The following is sample output from the successful analysis of a volume group:
Select an operation to perform: 1 . . . Select Volume Groups to analyze: [<pattern-list>,all,list,listvg,q,?] vg02 vg02 Analyze this Volume Group? [y,n,q,?] (default: y) y Conversion Analysis of the following devices was successful. /dev/sdf /dev/sdh1 Hit RETURN to continue. Second Stage Conversion Analysis of vg02 Volume Group vg02 has been analyzed and prepared for conversion. Volume Group Analysis Completed Hit RETURN to continue.
If off-disk data migration is required because there is insufficient space for on-disk data migration, you are prompted to select additional disks that can be used.
The analysis may fail for one of a number of reasons.
The messages output by vxvmconvert explain the type of failure, and detail actions that you can take before retrying the analysis.
- Back up your LVM configuration and user data before attempting the conversion to VxVM. Similarly, you should back up the LVM configuration itself.
Warning:
During a conversion, any spurious reboots, power outages, hardware errors, or operating system bugs can have unpredictable consequences. You are advised to safeguard your data with a set of verified backups.
Before running vxvmconvert, you can use the vgcfgbackup utility to save a copy of the configuration of an LVM volume group, as shown here:
# vgcfgbackup volume_group_name
This creates a backup file, /etc/lvmconf/volume_group_name.conf. Save this file to another location (such as off-line on tape or some other medium) to prevent the conversion process from overwriting it. If necessary, the LVM configuration can be restored from the backup file.
The vxvmconvert utility also saves a snapshot of the LVM configuration data during conversion of each disk. This data is saved in a different format from that of vgcfgbackup, and it can only be used with the vxvmconvert program. With certain limitations, you can use the data to reinstate the LVM volumes after they have been converted to VxVM. Even though vxvmconvert provides this mechanism for backing up the LVM configuration, you are advised to use vgcfgbackup to save the LVM configuration information for each LVM volume group.
Before performing a backup of the user data, note that backup procedures may have dependencies on the volume names that are currently in use on your system. Conversion to VxVM changes the volume names. You need to understand the implications that such name changes have for restoring from any backups that you make.
- Prevent access by applications to volumes in the volume groups to be converted. This may require you to stop databases, unmount file systems, and so on.
vxvmconvert attempts to unmount mounted file systems before starting conversion. However, it makes no attempt to stop applications that are using those file systems, nor does it attempt to deal with applications such as databases that are running on raw LVM volumes.
The LVM logical volumes to be converted must all be available to the vxvmconvert process. Do not deactivate the volume group or any logical volumes before running vxvmconvert.
You can use the following command to activate a volume group:
# vgchange -a y volume_group_name
- Start the conversion of each volume group by selecting item 2 Convert LVM Volume Groups to VxVM from the vxvmconvert main menu. The volume group is analyzed to ensure that conversion is possible. If the analysis is successful, you are asked whether you wish to perform the conversion.
Convert one volume group at a time to avoid errors during conversion.
The following is sample output from a successful conversion:
Select an operation to perform: 2 . . . Select Volume Groups to convert: [<pattern-list>,all,list,listvg,q,? vg02 vg02 Convert this Volume Group? [y,n,q,?] (default: y) y Conversion Analysis of the following devices was successful. /dev/sdf /dev/sdh1 Hit RETURN to continue. Second Stage Conversion Analysis of vg02 Volume Group vg02 has been analyzed and prepared for conversion. Are you ready to commit to these changes?[y,n,q,?](default: y) y vxlvmconv: making log directory /etc/vx/lvmconv/vg02.d/log. vxlvmconv: starting conversion for VG "vg02" - Thu Feb 26 09:08:57 IST 2004 vgchange -- volume group "vg02" successfully deactivated vxlvmconv: checking disk connectivity Starting Conversion of vg02 to VxVM fdisk .. disksetup .. dginit .. make . volinit .. vxlvmconv: Conversion complete. Convert other LVM Volume Groups? [y,n,q,?] (default: n)
If off-disk data migration is required because there is insufficient space for on-disk data migration, you are prompted to select additional disks that can be used.
- After converting the LVM volume groups, you can use the list operation in vxvmconvert to examine the status of the converted disks, as shown in this example:
Select an operation to perform: list . . . Enter disk device or "all"[<address>,all,q,?](default: all) all DEVICE DISK GROUP STATUS cciss/c0d0 - - online invalid cciss/c0d1 - - online sda - - online sdb disk01 rootdg online sdc disk02 rootdg online sdd disk03 rootdg online sde1 vg0101 vg01 online sdf vg0201 vg02 online sdg vg0102 vg01 online sdh1 vg0202 vg02 online Device to list in detail [<address>,none,q,?] (default: none)
The LVM disks that were previously shown in the error state are now displayed as online to VxVM.
You can also use the vxprint command to display the details of the objects in the converted volumes (the TUTIL0 and PUTIL0 columns are omitted for clarity):
# vxprint Disk group: rootdg TY NAME ASSOC KSTATE LENGTH PLOFFS STATE dg rootdg rootdg - - - - dm disk01 sdb - 17778528 - - dm disk02 sdc - 17778528 - - dm disk03 sdd - 17778528 - - Disk group: vg01 TY NAME ASSOC KSTATE LENGTH PLOFFS STATE dg vg01 vg01 - - - - dm vg0101 sde1 - 17774975 - - dm vg0102 sdg - 17772544 - - v stripevol gen ENABLED 1638400 - ACTIVE pl stripevol-01stripevol ENABLED 1638400 - ACTIVE sd vg0102-01 stripevol-01 ENABLED 819200 0 - sd vg0101-01 stripevol-01 ENABLED 819200 0 - Disk group: vg02 TY NAME ASSOC KSTATE LENGTH PLOFFS STATE dg vg02 vg02 - - - - dm vg0201 sdf - 17772544 - - dm vg0202 sdh1 - 17774975 - - v concatvol gen ENABLED 163840 - ACTIVE pl concatvol-01concatvol ENABLED 163840 - ACTIVE sd vg0202-02 concatvol-01 ENABLED 163840 0 - v stripevol gen ENABLED 81920 - ACTIVE pl stripevol-01stripevol ENABLED 81920 - ACTIVE sd vg0202-01 stripevol-01 ENABLED 40960 0 - sd vg0201-01 stripevol-01 ENABLED 40960 0 -
- Implement the changes to applications and configuration files that are required for the new VxVM volume names. (You prepared the information for this step in step 2.)
- File systems can now be mounted on the new devices, and applications can be restarted. If you unmounted any file systems before running vxvmconvert, remount them using their new volume names. The vxvmconvert utility automatically remounts any file systems that were left mounted.
- The disks in each new VxVM disk group are given VM disk media names that are based on the disk group name. For example, if a disk group is named mydg, its disks are assigned names such as mydg01, mydg02, and so on. Plexes within each VxVM volume are named mydg01-01, mydg01-02, and so on. If required, you can rename disks and plexes.
Only rename VxVM objects in the converted disk groups when you are fully satisfied with the configuration. Renaming VxVM objects prevents you from using vxvmconvert to restore the original LVM volume groups.