Dell PowerStore 3000X EMC PowerStore Monitoring Your System - Page 12

Data Savings features Data savings metrics are based on the automated inline data services that are provided with the PowerStore. The automated inline data services occur in the system before the data is written to the storage drives. The automated inline data services include: • Data reduction, which consists of deduplication and compression. • Thin provisioning, which enables multiple storage resources to subscribe to a common storage capacity. The drive usage that is saved by these data services results in cost savings and consistent, predictable high performance, regardless of workload. Data reduction The system achieves data reduction by using the following techniques: • Data deduplication • Data compression There is no performance impact from the use of data deduplication or compression. Data deduplication Deduplication is the process of consolidating redundancies that are contained within data to reduce storage overhead. With deduplication, only one copy of data is stored on drives. Duplicates are replaced with a reference that points back to the original copy. Deduplication is always enabled and cannot be disabled. Deduplication occurs before the data is written to storage drives. Deduplication provides the following benefits: • Enables high capacity growth without requiring a drastic increase in space, power, or cooling. • Improves drive endurance, because there are fewer writes to the drives. • Improves performance, because the system reads the deduplicated data from the cache instead of from the drives. Compression Compression is the process of reducing the number of bits needed to store and transmit data. Compression is always enabled, and cannot be disabled. Compression occurs before data it is written to storage drives. Inline compression provides the following benefits: • Saves storage capacity by storing data blocks efficiently. • Improves drive endurance, because there are fewer writes to the drives. There is no performance impact from compression. Reporting the capacity savings The system reports the capacity savings that is gained from data reduction using the Unique Data metric. The Unique Data metric is calculated for a volume and its associated clones and snapshots. Thin provisioning Storage provisioning is the process of allocating available drive capacity to meet the capacity, performance, and availability requirements of hosts and applications. In PowerStore, volumes and file systems are thin provisioned to optimize the use of available storage. Thin provisioning works as follows: • When you create a volume or file system, the system allocates an initial quantity of storage to the storage resource. This provisioned size represents the maximum capacity to which the storage resource can grow without being increased. The system reserves only a portion of the requested size, called the initial allocation. The requested size of the storage resource is called the subscribed quantity. • The system will only allocate physical space when data is written. A storage resource appears full when data written to the storage resource reaches the provisioned size of the storage resource. Since provisioned space is not physically allocated multiple storage resources could subscribe to the common storage capacity. Thin provisioning allows multiple storage resources to subscribe to a common storage capacity. Therefore, it allows organizations to purchase less storage capacity up front, and increase available drive capacity on an on-demand basis, according to actual storage usage. 12 Monitoring Capacity