Home > Workload Solutions > Oracle > White Papers > Dell PowerMax 2500 and 8500 Best Practices for Mission Critical Oracle Databases > Local replication using clones
As shown in Figure 12, PowerMax clones can be directly presented to hosts, restored directly to their clone source volumes, or used as a new source for local replications.
Clone operations are considered manual as clones do not have policies in Unisphere. Up to 256 clones can be created for each source volume.
Both snapshots and clones share storage allocations for high efficiency and performance, where only data differences consume additional storage capacity. Restoring data swaps data pointers rather than copying data. Metadata associated with snapshots and clones is scaled proportionally to the number of changes. These capabilities lead to better ease-of-use, efficiency, scalability, and performance.
Starting with PowerMaxOS 10, a new internal mechanism replaces the legacy define scan of snapshot metadata. As a result, there is no need to wait before performing snapshot cascaded operations such as creating a new snapshot from snapshot-linked target devices, or before unlinking a snapshot.
The copy and nocopy options, which are snapshot legacy features, are no longer used. All snapshots are space efficient (nocopy) and consume additional storage capacity only based on data changes after snapshot creation.
Note:
Clone creation requires the use of the -consistent flag to create consistent clones. This behavior may change in the future.
Snapshot and clone interoperability is not allowed on cascading sessions. For example, a snapshot cannot be taken from a clone target, and clones cannot be created from a volume that has a snapshot in restore state.
Table 10 shows a feature summary of both snapshots and clones:
Feature | SnapVX Snapshots | SnapVX Linked Targets |
|
Scalability (per SG) | 1024 | 1024 | 256 |
Integrated scheduling | P |
|
|
Nonmodifiable (protected) | P |
|
|
Secure | P |
|
|
R/W access |
| P | P |
Device expansion | P | P |
|
Direct restore to source | P |
| P |
Write-consistent | P | P | Requires the -consistent flag |
Ship data using SRDF |
| P | P |
Reset to original point-in-time copy |
| P |
|
For more information about PowerMax snapshots and clones, see the Dell PowerMax 2500 and 8500: TimeFinder SnapVX Snapshots and Clones White Paper.