Dell Storage Manager 2020 R1 Administrator's Guide

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About Volumes

Volumes provide the storage allocation structure within the PS Series group.

To access storage in a PS Series group, you allocate portions of a storage pool to volumes. You can create a volume on a single group member or one that spans multiple group members. You assign each volume a name, size, and a storage pool. The group automatically load balances volume data across pool members.

PS Series volumes — Figure 1. PS Series Volumes

Table 1. PS Series VolumesDescription of callouts used in PS Series Volumes figure
Callout	Description
1	PS Series group Storage area network (SAN) comprising one or more PS Series arrays connected to an IP network. Arrays are high-performance (physical) block storage devices.
2	PS Series members Each PS Series array is a member in the group and is assigned to a storage pool.
3	PS Series storage pools Containers for storage resources (disk space, processing power, and network bandwidth).
4	PS Series single-member pool A PS Series array represented as a member within a pool to which it is assigned.
5	PS Series multimember pool Multiple PS Series arrays represented as individual members within a pool to which it is assigned.
6	Storage space Space received from PS Series arrays to allocate data as needed through various structures (volumes, snapshots, thin provisioning, replicas, containers, SMB/NFS, quotas, and local users and groups).
7	Volume Provides the structure for the PS Series group.
8	Snapshot collections A collection of snapshots within the PS Series group.
9	Snapshots A point-in-time copy of data from a volume or container. Snapshots can be created manually or automatically on a schedule.
10	Thin-provisioned volume (offline) Thin provisioning allocates space based on how much is actually used, but gives the impression the entire volume size is available. (For example, a volume with 100GB storage can be allocated to use only 20GB, while the rest is available for other uses within the storage pool.) An offline volume indicates that it can no longer be accessed by the iSCSI initiator until it has been set online.

For each volume, the group generates an iSCSI target name, which you cannot modify. An iSCSI target name includes a prefix, a string, and the volume name. Initiators use the target name to connect to a volume. For example:

iqn.2001-05.com.equallogic:7-8b0900-6d0000000-001ebbc5d80sf0k0-db3

where:
prefix: iqn.2001-05.com.equallogic
string: 7-8b0900-6d0000000-001ebbc5d80sf0k0
volume name: db3

Each volume appears on the network as an iSCSI target. Hosts with iSCSI initiators use the volume's target name to connect to the volume.

Each iSCSI volume supports a set of features and capabilities:

Snapshots — To protect volume data from mistakes, viruses, or database corruption, you can use snapshots.
Replication — To protect against disasters, you can replicate volume data from one group to another.
Thin Provisioning — To manage storage capacity utilization on demand, you can use thin provisioning.
Clones — To create a boot image, full system backup, or transfer a system to another person, you can use cloning.
Volume Undelete — To restore mistakenly deleted volumes, you might be able to use volume undelete.
NOTE:The system permanently deletes volumes after 7 days, and sometimes sooner.
Volume Folders — To organize volumes into folders for quick visual reference, you can use volume folders.
Control Access to iSCSI Initiators — To protect your volumes from unauthorized and uncoordinated access by iSCSI initiators, you can use access control policies.
Control Access to Hosts (servers) — To prevent inadvertent corruption of the volume caused by multiple hosts writing to it in an uncoordinated manner, enable multihost access to a volume.