Administrator Guide
Table Of Contents
- Dell EMC Storage Systems Administrator Guide for the metro node appliance
- Contents
- Preface
- CLI Workspace and User Accounts
- Meta Volumes
- System Management
- Thin support in metro node
- Provisioning Storage
- Volume expansion
- Data migration
- About data migrations
- Migrating thin-capable storage
- About rebuilds
- One-time data migrations
- Batch migrations
- Prerequisites
- Creating a batch migration plan
- Checking a batch migration plan
- Modifying a batch migration file
- Starting a batch migration
- Pausing/resuming a batch migration (optional)
- Canceling a batch migration (optional)
- Monitoring a batch migration’s progress
- Viewing a batch migration’s status
- Committing a batch migration
- Cleaning a batch migration
- Removing batch migration records
- Configure the WAN Network
- Cluster Witness
- Consistency Groups
- Performance and Monitoring
- Metro node with active-passive storage arrays
Meta Volumes
This chapter describes the procedures to manage metadata and meta-volumes using the VPlexcli.
Topics:
• About meta-volumes
• Moving a meta-volume
• Renaming a meta-volume
• Deleting a meta-volume
• Displaying meta-volume
• Verifying consistency of a meta-volume
About meta-volumes
Metro node metadata includes virtual to physical mappings, data about devices, virtual volumes, and system configuration
settings.
Metadata is stored in cache and backed up on specially designated external volumes called meta-volumes.
Meta-volumes are created during system setup.
When a cluster is initially configured, the meta-volume must be the first storage presented to metro node. This prevents the
meta-volume from being accidentally overwritten.
After the meta-volume is configured, updates to the metadata are written to both the cache and the meta-volume when the
metro node configuration is modified.
Backup meta-volumes are point-in-time snapshots of the current metadata, and provide extra protection before major
configuration changes, refreshes, or migrations.
Metadata is read from the meta-volume only during the start of each director.
Meta-volume backups are created:
● Before migrating to a new array
● Before a major update.
Meta-volumes differ from standard storage volumes as mentioned below:
● A meta-volume is created without first being claimed
● Meta-volumes are created directly on storage volumes.
See the Configuration and Installation Guide for metro node for more details about the criteria to select storage used for
meta-volumes.
CAUTION: Do not configure the meta-volume on the vault drives of a storage array.
Meta-volume performance and availability requirements
Performance is not critical for meta-volumes. The minimum performance that is allowed is 40 MB/sec and 100 4 K IOP/second.
For non-flash arrays, the physical spindles for meta-volumes should be isolated from application workloads.
The following is recommended for meta-volumes:
● Read caching must be enabled
● A hot spare meta-volume must be pre-configured in case of a catastrophic failure of the active metavolume.
● If possible, do not use devices on LUN0. Paths to LUN0 are removed and added whenever its array goes through discovery.
This behavior is because LUN0 can be either a default LUN or a real LUN backed by real storage."
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