Storage Foundation 7.4.1 Administrator's Guide - Linux
- Section I. Introducing Storage Foundation
- Overview of Storage Foundation
- How Dynamic Multi-Pathing works
- How Veritas Volume Manager works
- How Veritas Volume Manager works with the operating system
- How Veritas Volume Manager handles storage management
- Volume layouts in Veritas Volume Manager
- Online relayout
- Volume resynchronization
- Dirty region logging
- Volume snapshots
- FastResync
- How VxVM handles hardware clones or snapshots
- Volume encryption
- How Veritas File System works
- Section II. Provisioning storage
- Provisioning new storage
- Advanced allocation methods for configuring storage
- Customizing allocation behavior
- Using rules to make volume allocation more efficient
- Understanding persistent attributes
- Customizing disk classes for allocation
- Specifying allocation constraints for vxassist operations with the use clause and the require clause
- Creating volumes of a specific layout
- Customizing allocation behavior
- Creating and mounting VxFS file systems
- Creating a VxFS file system
- Mounting a VxFS file system
- tmplog mount option
- ioerror mount option
- largefiles and nolargefiles mount options
- Resizing a file system
- Monitoring free space
- Extent attributes
- Section III. Administering multi-pathing with DMP
- Administering Dynamic Multi-Pathing
- Discovering and configuring newly added disk devices
- About discovering disks and dynamically adding disk arrays
- How to administer the Device Discovery Layer
- Administering DMP using the vxdmpadm utility
- Gathering and displaying I/O statistics
- Specifying the I/O policy
- Discovering and configuring newly added disk devices
- Dynamic Reconfiguration of devices
- Reconfiguring a LUN online that is under DMP control using the Dynamic Reconfiguration tool
- Manually reconfiguring a LUN online that is under DMP control
- Managing devices
- Displaying disk information
- Changing the disk device naming scheme
- Adding and removing disks
- Event monitoring
- Administering Dynamic Multi-Pathing
- Section IV. Administering Storage Foundation
- Administering sites and remote mirrors
- About sites and remote mirrors
- Fire drill - testing the configuration
- Changing the site name
- Administering the Remote Mirror configuration
- Failure and recovery scenarios
- Administering sites and remote mirrors
- Section V. Optimizing I/O performance
- Veritas File System I/O
- Veritas Volume Manager I/O
- Managing application I/O workloads using maximum IOPS settings
- Section VI. Using Point-in-time copies
- Understanding point-in-time copy methods
- When to use point-in-time copies
- About Storage Foundation point-in-time copy technologies
- Volume-level snapshots
- Storage Checkpoints
- About FileSnaps
- About snapshot file systems
- Administering volume snapshots
- Traditional third-mirror break-off snapshots
- Full-sized instant snapshots
- Creating instant snapshots
- Adding an instant snap DCO and DCO volume
- Controlling instant snapshot synchronization
- Creating instant snapshots
- Cascaded snapshots
- Adding a version 0 DCO and DCO volume
- Administering Storage Checkpoints
- Storage Checkpoint administration
- Administering FileSnaps
- Administering snapshot file systems
- Understanding point-in-time copy methods
- Section VII. Optimizing storage with Storage Foundation
- Understanding storage optimization solutions in Storage Foundation
- Migrating data from thick storage to thin storage
- Maintaining Thin Storage with Thin Reclamation
- Reclamation of storage on thin reclamation arrays
- Identifying thin and thin reclamation LUNs
- Veritas InfoScale 4k sector device support solution
- Section VIII. Maximizing storage utilization
- Understanding storage tiering with SmartTier
- Creating and administering volume sets
- Multi-volume file systems
- Features implemented using multi-volume file system (MVFS) support
- Adding a volume to and removing a volume from a multi-volume file system
- Volume encapsulation
- Load balancing
- Administering SmartTier
- About SmartTier
- Placement classes
- Administering placement policies
- File placement policy rules
- Multiple criteria in file placement policy rule statements
- Using SmartTier with solid state disks
- Sub-file relocation
- Administering hot-relocation
- How hot-relocation works
- Moving relocated subdisks
- Deduplicating data
- Compressing files
- About compressing files
- Use cases for compressing files
- Section IX. Administering storage
- Managing volumes and disk groups
- Rules for determining the default disk group
- Moving volumes or disks
- Monitoring and controlling tasks
- Performing online relayout
- Adding a mirror to a volume
- Managing disk groups
- Disk group versions
- Displaying disk group information
- Importing a disk group
- Moving disk groups between systems
- Importing a disk group containing hardware cloned disks
- Handling conflicting configuration copies
- Destroying a disk group
- Backing up and restoring disk group configuration data
- Managing plexes and subdisks
- Decommissioning storage
- Rootability
- Encapsulating a disk
- Rootability
- Sample supported root disk layouts for encapsulation
- Encapsulating and mirroring the root disk
- Administering an encapsulated boot disk
- Quotas
- Using Veritas File System quotas
- File Change Log
- Managing volumes and disk groups
- Section X. Reference
- Appendix A. Reverse path name lookup
- Appendix B. Tunable parameters
- Tuning the VxFS file system
- Methods to change Dynamic Multi-Pathing tunable parameters
- Tunable parameters for VxVM
- Methods to change Veritas Volume Manager tunable parameters
- Appendix C. Command reference
Encapsulating and mirroring the root disk
VxVM lets you mirror the root volume and other areas needed for booting onto another disk. This makes it possible to recover from failure of your root disk by replacing it with one of its mirrors.
Use the fdisk or sfdisk commands to obtain a printout of the root disk partition table before you encapsulate the root disk. For more information, see the appropriate manual pages. You may need this information should you subsequently need to recreate the original root disk.
See the Veritas InfoScale Troubleshooting Guide.
You can use the vxdiskadm command to encapsulate the root disk.
You can also use the vxencap command, as shown in this example where the root disk is sda:
# vxencap -c -g diskgroup rootdisk=sda
where diskgroup must be the name of the current boot disk group. If no boot disk group currently exists, one is created with the specified name. The name bootdg is reserved as an alias for the name of the boot disk group, and cannot be used. You must reboot the system for the changes to take effect.
Both the vxdiskadm and vxencap procedures for encapsulating the root disk also update the /etc/fstab file and the boot loader configuration file (/boot/grub/menu.lst or /etc/grub.conf (as appropriate for the platform) for GRUB or /etc/lilo.conf for LILO):
Entries are changed in /etc/fstab for the rootvol, swapvol and other volumes on the encapsulated root disk.
A special entry, vxvm_root, is added to the boot loader configuration file to allow the system to boot from an encapsulated root disk.
The contents of the original /etc/fstab and boot loader configuration files are saved in the files /etc/fstab.b4vxvm, /boot/grub/menu.lst.b4vxvm or /etc/grub.conf.b4vxvm for GRUB, and /etc/lilo.conf.b4vxvm for LILO.
Warning:
When modifying the /etc/fstab and the boot loader configuration files, take care not to corrupt the entries that have been added by VxVM. This can prevent your system from booting correctly.
To mirror the root disk onto another disk after encapsulation
- Choose a disk to use for the mirror that is at least as large as the existing root disk, whose geometry is seen by Linux to be the same as the existing root disk, and which is not already in use by VxVM or any other subsystem (such as a mounted partition or swap area). The disk should be visible to the Basic Input Output System (BIOS) and to the bootloader of the operating system.
- Select Mirror Volumes on a Disk from the vxdiskadm main menu to create a mirror of the root disk. (These automatically invoke the vxrootmir command if the mirroring operation is performed on the root disk.)
The disk that is used for the root mirror must not be under Volume Manager control already.
- Alternatively, to mirror all file systems on the root disk, run the following command:
# vxrootmir mirror_da_name mirror_dm_name
mirror_da_name is the disk access name of the disk that is to mirror the root disk, and mirror_dm_name is the disk media name that you want to assign to the mirror disk. The alternate root disk is configured to allow the system to be booted from it in the event that the primary root disk fails. For example, to mirror the root disk, sda, onto disk sdb, and give this the disk name rootmir, you would use the following command:
# vxrootmir sdb rootmir
The operations to set up the root disk mirror take some time to complete.
The following is example output from the vxprint command after the root disk has been encapsulated and its mirror has been created (the TUTIL0 and PUTIL0 fields and the subdisk records are omitted for clarity):
Disk group: rootdg TY NAME ASSOC KSTATE LENGTH PLOFFS STATE ... dg rootdg rootdg - - - - dm rootdisk sda - 16450497 - - dm rootmir sdb - 16450497 - - v rootvol root ENABLED 12337857 - ACTIVE pl mirrootvol-01 rootvol ENABLED 12337857 - ACTIVE pl rootvol-01 rootvol ENABLED 12337857 - ACTIVE v swapvol swap ENABLED 4112640 - ACTIVE pl mirswapvol-01 swapvol ENABLED 4112640 - ACTIVE pl swapvol-01 swapvol ENABLED 4112640 - ACTIVE