Snapshots (Host Volume); Snapshot Faq; Snapshot Types (Allocation Policy) - HP 418800-B21 - StorageWorks Modular Smart Array 70 Storage Enclosure User Manual

• Yes. All virtual disks that underlie the host volume comply with snapclone guidelines. Snapclone
replication can be performed.
• No. One or more virtual disks that underlie the host volume do not comply with snapclone
guidelines. Snapclone replication cannot be performed.
See also virtual disks snapclones,

Snapshots (host volume)

Snapshot replication of a host volume instantly creates a virtual, point-in-time copies of the virtual disks
that underlie a host volume. The copies are called snapshots.
The snapshot property indicates whether the host volume can be locally replicated using the snapshot
method. Values are:
• Yes. All virtual disks that underlie the host volume comply with snapshot guidelines. Snapshot
replication can be performed.
• No. One or more virtual disks that underlie the host volume do not comply with snapshot
guidelines. Snapshot replication cannot be performed.
See also virtual disks snapshots,

Snapshot FAQ

• How can I tell a snapshot from other types of virtual disks?
Because snapshots are not independent virtual disks, they are identified differently than original
virtual disks. See virtual disks types.
• How long does it take to create a snapshot?
A snapshot requires only a matter of seconds, no matter how large the original virtual disk.
• If it is virtual, can a host write to a snapshot?
Yes. A snapshot is functionally equivalent to a physical disk with both read and write capability.
• After I create a snapshot, can I delete the original virtual disk?
No. A snapshot always relies, at least in part, on the original (active) virtual disk for data. If the
original virtual disk is deleted, its associated snapshot becomes unusable. A snapshot should
be thought of as a temporary copy.
• Can I make multiple snapshots of an original virtual disk?
Yes. However, there is a limit. See virtual disks
• What is the maximum number of snapshots on a storage system?
There is no limit. However, the greater the number of snapshots, the longer it takes to shut down
the storage system during maintenance and upgrade activities.
• Can I create a snapshot of a snapclone?
Yes.
• Can I create an snapshot of a snapshot?
No.

Snapshot types (allocation policy)

Snapshot types (allocation policy) specifies how the storage system allocates space in a disk group
for a snapshot. Values are:
• Demand allocated. The space reserved for the snapshot can automatically change from an initial
minimum amount, up to the full capacity of the original virtual disk.
• Fully allocated. The space reserved for the snapshot is initially set to, and remains fixed at, the full
capacity of the source virtual disk.
When selecting a snapshot type, one consideration is the lifetime of the snapshot and the amount of
source data that will change during its lifetime.
snapclone FAQ and snapclone
snapshot types, snapshot FAQ
snapshot
HP StorageWorks Replication Solutions Manager 4.0.1
guidelines.
and snapshot guidelines.
guidelines.
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