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ME4 Series storage includes a comprehensive set of software features in an all-inclusive license. The following sections provide a summary of the ME4 Series software features. For more information, see the ME4 Series Administrator's Guide on Dell.com/support.
ME4 Series arrays support two storage technologies: virtual and linear storage.
Virtual storage is the foundation for data-management features such as thin provisioning, automated tiered storage (ATS), and other virtualization features. Virtual storage virtualizes the physical devices and creates virtual volumes that reside in virtual disk groups. A virtual volume is a set of pages that are mapped to the physical devices. A virtual volume can span across more than 16 physical devices which is highly flexible and efficient. It also offers excellent performance because it scales with the number of physical devices in the pool.
Linear storage does not virtualize the logical data on the physical devices. It stores data in sequential, fully allocated physical blocks and the mapping is static. Although it offers better performance for certain sequential workloads, it is inflexible, and many virtualization features such as tiering, snapshots, and replications are not available on linear pools. The most common use case for linear storage is for video archiving.
In most cases, Dell Technologies recommends using virtual storage with ME4 Series systems.
ME4 Series arrays support RAID data protection levels NRAID, 0, 1, 10, 3, 5, 50, 6 and ADAPT. ADAPT is a special RAID implementation that offers some unique benefits. It can withstand two drive failures with very fast rebuilds. Spare capacity is distributed across all drives instead of dedicated spare drives. ADAPT disk groups can have up to 128 drives and allow mixing different drive sizes. Data is stored across all disks evenly. The storage system automatically rebalances the data when new drives are added or when the distribution of data has become imbalanced.
It is recommended to choose the right RAID level that best suits the type of workloads in the environment. Review the information in ME4 Series Administrator's Guide which details the benefits of each RAID level, the minimum and maximum disks requirements, and the recommendation of RAID levels for popular workloads.
Virtual volumes are thin provisioned in the storage system where pages are allocated only when the data is written to the volume. This allows the storage system to appear to have more storage than what is actually allocated. It also allows more efficient usage because the consumption is based on the actual amount of data written and not on the defined volume size.
When the storage system is configured with different types of disks, the automated tiered storage (ATS) feature automatically moves data between different disk classes based on data-access patterns to optimize performance and space consumption. There are three storage tiers: Performance, Standard and Archive. The performance tier uses SSDs, the standard tier uses lower-cost HDD SAS disks, and the archive tier uses lowest-cost, large-capacity NL-SAS disks.
The storage system can create point-in-time copies of virtual volumes. Snapshot creation is fast and efficient because only changed data in the snapshot consumes space. See the section Using snapshots to roll back or reset a volume about data protection with snapshots.
Virtual volumes and snapshots can be replicated asynchronously to a remote ME4 Series system. This feature can be used for disaster recovery, to distribute data, or to archive data to an offsite location. Replication requires dedicated I/O ports and therefore reduces the number of ports that can be used for host connectivity.
ME4 Storage System supports full-disk encryption (FDE) using self-encrypting drives (SEDs). The data and system are secured on the disks and are accessed using passphrases and lock keys that are only available on the storage system. FDE operates on a per-system basis. To use FDE, all disks in the system must be FDE-capable.
ME Storage Manager is a web-based interface for configuring, monitoring, and managing the storage system. It can be accessed through each controller's embedded web server.
The storage system provides a full-feature command-line interface (CLI) that enables administrators to manage and configure the storage system. The CLI software is embedded in the controller modules and can be accessed through HTTPS, HTTP, SSH, Telnet over the network, or by directly connecting to the controller's serial CLI port. In addition to the interactive CLI console format, the CLI API format allows external programs to interact with the system through XML and JSON formats. To script CLI commands, the CLI API format is recommended because it is expected to remain consistent from release to release. For a complete description of the CLI commands, see the ME4 Series CLI Guide on Dell.com/support.