HP 418800-B21 HP StorageWorks Replication Solutions Manager 4.0.1 user guide ( - Page 151

• 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, snapclone FAQ and snapclone guidelines. 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 types, snapshot FAQ and snapshot guidelines. 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 snapshot guidelines. • 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. HP StorageWorks Replication Solutions Manager 4.0.1 151