Storage Foundation 8.0 Administrator's Guide - Windows
- Overview
- Setup and configuration
- Function overview
- About the client console for Storage Foundation
- Recommendations for caching-enabled disks
- Configure basic disks (Optional)
- About creating dynamic disk groups
- About creating dynamic volumes
- Set desired preferences
- Using the GUI to manage your storage
- Working with disks, partitions, and volumes
- Adding storage
- Disk tasks
- Remove a disk from the computer
- Veritas Disk ID (VDID)
- General Partition/Volume tasks
- Mount a volume at an empty folder (Drive path)
- Expand a dynamic volume
- Shrink a dynamic volume
- Basic disk and volume tasks
- Automatic discovery of SSD devices and manual classification as SSD
- Volume Manager space allocation is SSD aware
- Dealing with disk groups
- Disk groups overview
- Delete a dynamic disk group
- Detaching and attaching dynamic disks
- Importing and deporting dynamic disk groups
- Partitioned shared storage with private dynamic disk group protection
- Fast failover in clustered environments
- iSCSI SAN support
- Settings for monitoring objects
- Event monitoring and notification
- Event notification
- Configuring Automatic volume growth
- Standard features for adding fault tolerance
- Performance tuning
- FlashSnap
- FlashSnap components
- FastResync
- Snapshot commands
- Dynamic Disk Group Split and Join
- Dynamic disk group join
- Using Dynamic Disk Group Split and Join with a cluster on shared storage
- Dynamic Disk Group Split and Join troubleshooting tips
- Fast File Resync
- Volume Shadow Copy Service (VSS)
- Using the VSS snapshot wizards with Microsoft Exchange
- Using the VSS snapshot wizards with Enterprise Vault
- Using the VSS snapshot wizards with Microsoft SQL
- Copy on Write (COW)
- Using the VSS COW snapshot wizards with Microsoft Exchange
- Using the VSS COW snapshot wizards with Microsoft SQL
- Configuring data caching with SmartIO
- Typical deployment scenarios
- About cache area
- Configuring SmartIO
- Frequently asked questions about SmartIO
- Dynamic Multi-Pathing
- Configuring Cluster Volume Manager (CVM)
- Configuring a CVM cluster
- Administering CVM
- Access modes for cluster-shared volumes
- Storage disconnectivity and CVM disk detach policy
- Unconfiguring a CVM cluster
- Command shipping
- About I/O Fencing
- Administering site-aware allocation for campus clusters
- SFW for Hyper-V virtual machines
- Introduction to Storage Foundation solutions for Hyper-V environments
- Live migration support for SFW dynamic disk group
- Preparing the host machines
- Configuring the SFW storage
- Administering storage migration for SFW and Hyper-V virtual machine volumes
- Optional Storage Foundation features for Hyper-V environments
- Microsoft Failover Clustering support
- Configuring a quorum in a Microsoft Failover Cluster
- Implementing disaster recovery with Volume Replicator
- Troubleshooting and recovery
- Using disk and volume status information
- Resolving common problem situations
- Commands or procedures used in troubleshooting and recovery
- Rescan command
- Repair volume command for dynamic mirrored volumes
- Additional troubleshooting issues
- Disk issues
- Volume issues
- Disk group issues
- Connection issues
- Issues related to boot or restart
- Cluster issues
- Dynamic Multi-Pathing issues
- vxsnap issues
- Other issues
- CVM issues
- Appendix A. Command line interface
- Overview of the command line interface
- vxclustadm
- vxvol
- vxdg
- vxclus
- vxdisk
- vxassist
- vxassist (Windows-specific)
- vxsd
- vxedit
- vxdmpadm
- vxcbr
- vxsnap
- vxscrub
- sfcache
- Tuning SFW
- Appendix B. VDID details for arrays
Mirrored volumes
A mirrored volume is a fault-tolerant volume that duplicates your data on two or more physical disks. A mirror provides redundancy by simultaneously writing the same data onto two or more separate mirrors (or plexes) that reside on different disks. If one of the disks fails, data continues to be written to and read from the unaffected disk or disks.
Mirrored volumes protect the data on the disk from media failure. Mirroring reduces the chance of an unrecoverable error by providing duplicate sets of data, but it also multiplies the number of disks required for data storage and the input/output (I/O) operations when writing to the disk. However, some performance gains are achieved for reading data because of I/O load balancing of requests between the plexes. A mirrored volume is about the same as a RAID-5 volume in read operations but faster in write operations.
You can create a mirrored volume with the Create Volume wizard, or you can add a mirror to an existing volume with the Add Mirror wizard. To create a mirrored volume on two or more disks, each mirror or plex of the original volume requires space that is at least the same size as the original volume. When you create a mirror, the same drive letter is used for all plexes of the volume. If you have sufficient disks available, you can create multiple mirrors for extra redundancy (up to the limit of 32 mirrors). Then, you can break off a mirror to use for backup, data analysis, or testing without losing redundancy.
Note:
Adding a mirror to a volume involves a certain amount of time for mirror resynchronization. The SmartMove feature can help reduce mirror resynchronization time.
Breaking off a plex of the mirrored volume does not delete the information, but it does mean that the plex that is broken off no longer mirrors information from the other plex or plexes in the mirrored volume. The broken-off plex is assigned a different drive letter than that of the original mirrored volume. It is no longer part of the mirrored volume, but it retains its other volume layout characteristics. For example, if you had a mirrored striped volume, the broken-off plex would become a striped volume.
In the case of an unrecoverable error on a plex within a mirrored volume, you need to remove the plex that is damaged with the Remove Mirror command. You then can use the Add Mirror command to create a new plex on another disk to take the place of the damaged plex.
When you want to use the space in a mirrored volume for other purposes, you can remove a plex and return the space that it used to unallocated space.
Storage Foundation lets you add a mirror to any kind of dynamic volume, except RAID-5. You can extend any mirrored volume.
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