Snapshot Guidelines; Snapshots Per Virtual Disk; Snapshot Types (Allocation Policy) - HP 418800-B21 - StorageWorks Modular Smart Array 70 Storage Enclosure User Manual

• Can I create a snapshot of a snapclone?
Yes.
• Can I create an snapshot of a snapshot?
No.

Snapshot guidelines

The following guidelines apply to snapshot virtual disks:
• The array must have a local replication license. See
• The maximum number of snapshots per source varies with controller software versions. See
controller software features - local
• A snapshot is always created in the same disk group as the source virtual disk.
• The redundancy level (Vraid) of a snapshot must be the same or lower than the source. See
redundancy level
• All snapshots of the same virtual disk must be the same type (demand allocated or fully allocated)
and redundancy level. See
• Demand-allocated snapshots can run out of space if the disk group has insufficient space for the
snapshots to grow. In this event, the array stops writing to both the source and the snapshots.
• Snapshots count against the maximum number of virtual disks per array.
Snapshots cannot be created when the disk to be replicated is:
• A snapshot
• In the process of normalizing or being deleted. See normalization.

Snapshots per virtual disk

In HP XCS controller software, the maximum number of snapshots per virtual disk varies with the size of
the disk. This is because the total snapshot size (per disk) cannot exceed 15 TB.
Virtual disk snapshot estimator
Source size (TB)
0 < to 0.94
0.95 to 1.00
1.01 to 1.07
1.08 to 1.15
1.16 to 1.25
1.26 to 1.36
1.37 to 1.50
1.51 to 1.67
1.68 to 1.88
1.89 to 2.00
The maximum size of a virtual
disk is 2 TB.

Snapshot types (allocation policy)

Snapshot types (allocation policy) specifies how the storage system allocates space in a disk group
for a snapshot. Values are:
replication.
(Vraid).
snapshot types (allocation
Snapshots (max)
16
15
14
13
12
1 1
10
9
8
7
replication licenses
policy).
HP StorageWorks Replication Solutions Manager 4.0.1
overview.
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