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
Automatic plex reattachment
When a mirror plex encounters irrecoverable errors, Veritas Volume Manager (VxVM) detaches the plex from the mirrored volume. By default, VxVM automatically reattaches the affected mirror plexes when the underlying failed disk or LUN becomes visible. When VxVM detects that the device is online, the VxVM volume components on the involved LUN are automatically recovered, and the mirrors become usable.
VxVM uses the DMP failed LUN probing to detect when the device has come online. The timing for a reattach depends on the dmp_restore_interval, which is a tunable parameter. The number of LUNs that have reconnected may also affect the time required before the plex is reattached.
VxVM does not automatically reattach plexes on site-consistent volumes.
When VxVM is installed or the system reboots, VxVM starts the vxattachd daemon. The vxattachd daemon handles automatic reattachment for both plexes and sites. Thevxattachd daemon also initiates the resynchronization process for a plex. After a plex is successfully reattached, vxattachd notifies root.
To disable automatic plex attachment, remove vxattachd from the start up scripts. Disabling vxattachd disables the automatic reattachment feature for both plexes and sites.
In a Cluster Volume Manager (CVM) the following considerations apply:
If the global detach policy is set, a storage failure from any node causes all plexes on that storage to be detached globally. When the storage is connected back to any node, the vxattachd daemon triggers reattaching the plexes on the master node only.
The automatic reattachment functionality is local to a node. When enabled on a node, all of the disk groups imported on the node are monitored. If the automatic reattachment functionality is disabled on a master node, the feature is disable on all shared disk groups and private disk groups imported on the master node.
The vxattachd daemon listens for "dmpnode online" events using vxnotify to trigger its operation. Therefore, an automatic reattachment is not triggered if the dmpnode online event is not generated when vxattachd is running. The following are typical examples:
Storage is reconnected before vxattachd is started; for example, during reboot.
In CVM, with active/passive arrays, if all nodes cannot agree on a common path to an array controller, a plex can get detached due to I/O failure. In these cases, the dmpnode will not get disabled. Therefore, after the connections are restored, a dmpnode online event is not generated and automatic plex reattachment is not triggered.
These CVM considerations also apply to automatic site reattachment.