HP StoreEasy 1000 Administrator's Manual

Also see for StorageWorks 1000 - Modular Smart Array: Network guide Reference guide Technical white paper Firmware update Overview

Contents

Expanding storage using the Array Configuration UtilityThe Array Configuration Utility enables online capacity expansion of the array and logical drivefor specific MSA storage arrays, such as the P2000. For more information, use the ACU onlinehelp, or the procedures to “Expand Array” in the HP Array Configuration Utility User Guide.Expand logical driveThis option in the ACU increases the storage capacity of a logical drive by adding unused spaceon an array to the logical drive on the same array. The unused space is obtained either byexpanding an array or by deleting another logical drive on the same array. For more information,use the ACU online help, or the “Extend logical drive” procedure in the HP Array ConfigurationUtility User Guide.Volume shadow copiesNOTE: Select storage systems can be deployed in a clustered as well as a non-clusteredconfiguration. This chapter discusses using shadow copies in a non-clustered environment.The Volume Shadow Copy Service provides an infrastructure for creating point-in-time snapshots(shadow copies) of volumes. Shadow Copy supports 64 shadow copies per volume.A shadow copy contains previous versions of the files or folders contained on a volume at a specificpoint in time. While the shadow copy mechanism is managed at the server, previous versions offiles and folders are only available over the network from clients, and are seen on a per folder orfile level, and not as an entire volume.The shadow copy feature uses data blocks. As changes are made to the file system, the ShadowCopy Service copies the original blocks to a special cache file to maintain a consistent view of thefile at a particular point in time. Because the snapshot only contains a subset of the original blocks,the cache file is typically smaller than the original volume. In the snapshot's original form, it takesup no space because blocks are not moved until an update to the disk occurs.By using shadow copies, a storage system can maintain a set of previous versions of all files onthe selected volumes. End users access the file or folder by using a separate client add-on program,which enables them to view the file in Windows Explorer. Accessing previous versions of files, orshadow copies, enables users to:• Recover files that were accidentally deleted. Previous versions can be opened and copied toa safe location.• Recover from accidentally overwriting a file. A previous version of that file can be accessed.• Compare several versions of a file while working. Use previous versions to compare changesbetween two versions of a file.Shadow copies cannot replace the current backup, archive, or business recovery system, but theycan help to simplify restore procedures. Because a snapshot only contains a portion of the originaldata blocks, shadow copies cannot protect against data loss due to media failures. However, thestrength of snapshots is the ability to instantly recover data from shadow copies, reducing thenumber of times needed to restore data from tape.Shadow copy planningBefore setup is initiated on the server and the client interface is made available to end users,consider the following:• From what volume will shadow copies be taken?• How much disk space should be allocated for shadow copies?• Will separate disks be used to store shadow copies?• How frequently will shadow copies be made?56 File server management