HP MSA 1040 HP MSA 1040 SMU Reference Guide (762784-001, March 2014) - Page 22

• No-mirror. In this mode each controller stops mirroring its cache metadata to the partner controller. This improves write I/O response time but at the risk of losing data during a failover. ULP behavior is not affected, with the exception that during failover any write data in cache will be lost. • Atomic write. Not supported. Related topics • "Changing a volume's cache settings" (page 56) • "Changing system cache settings" (page 50) • "Viewing information about a volume" (page 104) About managing remote systems You can add a management object to obtain information from a remote storage system. This allows a local system to track remote systems by their network-port IP addresses and cache their login credentials - the user name and password for a user with the Manage role on that system. The IP address can then be used in commands that need to interact with the remote system. After a remote system has been added, you can check the connectivity of host ports in the local system to host ports in that remote system. A port in the local system can only link to ports with the same host interface, such as Fibre Channel (FC), in a remote system. Communication between local and remote systems is an essential part of the remote replication feature. Related topics • "Adding a remote system" (page 53) • "Deleting remote systems" (page 54) • "Viewing information about a remote system" (page 120) • "Checking links to a remote system" (page 90) • "About the Remote Snap replication feature" (page 121) About the Snapshot feature Snapshot is a licensed feature that provides data protection by enabling you to create and save snapshots of a volume. A base of 64 snapshots is included with all 1040 systems without an additional license. Each snapshot preserves the source volume's data state at the point in time when the snapshot was created. Snapshots can be created manually or by using the task scheduler. When the first snapshot is taken of a standard volume, the system automatically converts the volume into a master volume and reserves additional space for snapshot data. This reserved space, called a snap pool, stores pointers to the source volume's data. Each master volume has its own snap pool. The system treats a snapshot like any other volume; the snapshot can be mapped to hosts with read-only access, read-write access, or no access, depending on the snapshot's purpose. Any additional unique data written to a snapshot is also stored in the snap pool. 22 Getting started