Dell's Enterprise Hard Drives

Dell's Enterprise Hard Drives
Dell puts its Enterprise Hard Drive offerings through a rigorous validation process before they are ever considered as additions to its line of PowerVault storage systems and PowerEdge servers. Only the very best drives meeting exacting specifications such as those for performance, duty cycles, Mean Time Between Failure (MTBF) and rotational vibration necessary for an enterprise-level environment are accepted for customer usage. 
In order to provide ongoing support, Dell provides a patented online firmware update capability via the Dell Update Package (DUP). The DUP process translates to less downtime due to firmware maintenance updates.
Types of drives and best fits:
To further classify peripheral storage offerings, hard drives come in several varieties individually designed to address differing customer needs. These include
SSD: Enterprise-class solid-state drives fastest storage medium for random I/O (input/output). Also known as Tier-0.
SAS: 10K and 15K SAS drives
Also known as Tier-1, these 10K and 15K rpm Serial Attached SCSI (SAS) drives provide the online enterprise performance and availability needed for mission-critical applications. The dual-port point-to-point SAS interface provides:
  • Highest reliability and performance out of the hard-drive offerings
  • Fast time-to-data through their low rotational latency and fast seek times
  • A good balance between high IOPS (Input/Output operations per second), MB/second throughput and capacity
  • 1.6M hour MTBF
  • 24x7x365 operations
  • Availability of data through both ports simultaneously
SATA: Nearline SAS and Enterprise SATA drives
Also known as Tier-2, these nearline, business-critical 5.4K and 7.2K rpm drives combine specific design and manufacturing processes for hard drives rated at 24x7x365 operations for true enterprise duty cycles. The main emphasis is on an exceptional dollars/gigabyte advantage over Tier-1 storage. This drive classification includes: 
  • Nearline SAS — Combines the head, media and rotational speed of traditional enterprise-class SATA drives with the fully capable SAS interface typical of 10K/15K rpm SAS drives. These drives are rated at 1.2 million hours MTBF.
  • Enterprise SATA — True enterprise-class specifications, rated at 1.2 million hours MTBF, these drives provide the traditional SATA interface, but with capabilities far exceeding consumer grade SATA drives.
Dell enterprise solid-state drives 
Dell Enterprise Solid State Drives 
Dell's solid-state drive portfolio
Dell offers different solid-state drive (SSD) solutions to meet different customer needs. Enterprise SSDs as a class are unique to client or consumer-based SSD in terms of reliability, performance and architecture. While consumer-based SSDs, such as those utilized in notebooks are designed with a focus on consumer-based workloads, rigidity and battery life, enterprise-class SSDs are designed around enterprise application I/O (input/output) requirements with the primary attribute focus being on random I/O performance and reliability.
Dell enterprise solid-state drive attributes
Understanding the basics of enterprise-class SSDs allow customers to measure apples-to-apples when comparing solutions.
SLC vs MLC: SLC stands for single-level cell and references the number of information bits that can be stored in each cell of flash memory. For SLC this is one bit per cell. MLC stands for multilevel cell and can store multiple bits of information per cell. SLC-based Flash has a write endurance capability roughly 10X of what MLC Flash is capable of. Today, Dell PowerEdge, EqualLogic and Dell EMC SSD solutions utilize SLC-based Flash.
Over-provisioning: The Achilles' heel of SSD are their write performance. To rewrite an area of an SSD that has already been written, the data must be erased and then written. In order to overcome a portion of the write performance penalty, Dell enterprise SSD found across Dell PowerEdge, EqualLogic and Dell EMC, all employ a practice known as over-provisioning of Flash. This practice keeps native Flash capacity beyond the user-defined capacity, and utilizes the additional space as a scratch pad of sorts to quickly put down application write data on areas of Flash that are already in an erased state. The SSDs perform cleanup functions of this over-provisioned Flash space during time periods typically not impacting application performance.
SSD solutions throughout Dell's enterprise
Dell blade server: SATA Repeater + SSD without Hardware RAID support: This solution is targeted at transactional applications where the SSD is utilized as a method of increasing system performance over hard disk drives (HDDs) by providing a higher-speed, lower-power alternative for applications used as swap space, indexing or other transactional data. This SSD solution also offers a low-power boot drive option for blades.
Dell blade server: Modular PERCi RAID Controller + SSD with Hardware RAID support: Available in both 1/2 height and full-height blade servers, this PERC-enabled blade SSD solution is targeted primarily as tier-0 storage for application environments accessing randomly stored data where the time-to-data is a must.
Dell 11G rack and tower servers: PERCi RAID Controller + SSD with Hardware RAID support: Dell's 11G rack and tower servers provide for a true multi-tiered storage environment. The ability to create and manage multiple RAID sets on a single server allows customers to define how they allocate high-speed SSD storage versus slower, but more dollar-per-gigabyte friendly traditional SAS or Serial ATA (SATA) rotating media-based hard drives.
Dell EqualLogic storage arrays: SSDs-enabled acceleration: Dell EqualLogic PS6000 Series storage arrays offer ultrafast SSD solutions aimed at high I/O applications such as virtualization and online transaction processing (OLTP) applications resulting in up to 75 percent improvement in transaction throughput and up to a 60 percent improvement in response times.
Dell's SSD solution portfolio empowers customers to pick the performance-and-cost solution best suited for their enterprise .
10K and 15K SAS drives  
PowerVault Md1220Summary for Enterprise 10K and 15K SAS
  • Best performance and reliability within enterprise hard drives
  • Dual port with full duplex operations
  • Online firmware update through Dell Update Package (DUP)
  • High reliability
  • Available in PowerEdge servers and PowerVault enclosures
SAS hard drives are true dual-port full duplex capable devices. This means that both ports on a Serial Attached SCSI (SAS) drive can simultaneously send or receive data (host dependent). Available in 2.5” and 3.5” form factors, SAS hard drives rotating at 10,000 and 15,000 revolutions per minute (rpm) are known as tier-1, online and mission-critical devices. SAS drives at 10K and 15K offer the highest reliability of the Dell enterprise hard drive offerings at a 1.6 million hours MTBF (mean time between failure) rating. Also described as traditional enterprise, 10K and 15K SAS drives deliver the highest performance plus the highest reliability available in a rotating media storage device from Dell.
These 10K and 15K SAS drives are developed for the exacting requirements of speed and reliability due in mission-critical applications. In order to achieve this level of performance there are multiple features of these drives that provide an advantage over the tier-2 class used in business-critical applications. These frequently include:
PowerEdge R170
  • Higher quality sealing to prevent contamination
  • More shrouding and air control devices to maintain air pressure quality
  • Smaller platters with higher spin rates reducing access times
  • Faster seeks due to larger magnets, better bearings and stiffer actuators
  • Longer and more stringent factory tests to ensure the best-quality drives
  • Higher-quality motor to maintain the tight tolerances required at these higher speeds
  • Better design margin to handle rotational vibration issues. 
These are just some of the features allowing these drives to have a better reliability (1.6 million hours MTBF) and higher performance than their tier-2 cousins.
Available in both PowerEdge servers and PowerVault enclosures, Dell’s SAS interface and SAS hard drives are the successors to the SCSI and SCSI hard drives previously found in the enterprise. The key difference is that SAS is a point-to-point interface whereas SCSI was a bus-based interface. Pont-to-point means each device has its own full-bandwidth connection, based on each specific drive/controller, match up in capabilities as opposed to a bus-based interface where the entire set of devices on a bus would have to negotiate down to the slowest device. Today's SAS drives transfer data at rates at 3 gigabit per second, moving to as high as 6 gigabit per second in December 2009.
Dell SAS drives also have controlled firmware that has been specifically developed and tested for compatibility with select Dell RAID controllers delivering high reliability along with the assurance of compatibility for your information. Combined with the DUP, hard drive firmware can be updated on most hard drives without taking down the storage subsystem. Less downtime means higher productivity.
Nearline SAS and Enterprise SATA: 
PowerVault MD1220 Summary for Nearline SAS
  • Tier-2 dollar per gigabyte advantage of SATA
  • Up to 30% performance improvement over similar SATA 7,200 rpm drives
  • Dual port without an interposer means less interconnects
  • Available in PowerEdge servers and PowerVault enclosures

Dell's nearline Serial Attached SCSI (SAS), available in PowerEdge servers and PowerVault enclosures, is an enterprise hard drive combining the head, media and rotational speed of traditional enterprise-class Serial ATA (SATA) drives with the fully capable SAS interface typical of 10K/15K rpm SAS drives. These features provide a clear edge over enterprise SATA drives.

While SAS 10K and 15K rpm online hard drives are primarily used for applications considered mission-critical and needing data readily available, nearline refers to data that is one step removed from the fastest access online data but still critical to business operations. Nearline SAS and enterprise SATA together represent the tier-2 classification of hard drive storage.
Enterprise SATA and nearline SAS drives both offer the dollar-per-gigabyte advantage of tier-2 storage. Nearline SAS has advantages over SATA in terms of connectivity and performance. External storage environments cannot easily utilize SATA drives due to the signal integrity issues associated with SATA drives, as they are placed farther and farther away from the nearest interconnect. To address the signal integrity issues, often an interposer is included. In addition to addressing the signal integrity issues, most interposers also add in the functionality of an additional port, or connection to the drive, for failover purposes. Nearline SAS drives already have the signal integrity required for external storage along with dual ports capable of full-duplex operation (where supported by the controller). Because nearline SAS already has these features natively, it allows the elimination of the additional interconnect of the interposer. PowerVault MD 1200

Where host-based server storage is the application, nearline SAS still offers benefits over enterprise SATA. Nearline SAS has the processing power typically found on higher-end tier-1 10K and 15K rpm SAS drives. This processing power combined with the efficiencies of SAS around queuing technology, allows for up to a 30% improvement in performance for nearline SAS drives when operating in random I/O (input/output) environments.

Summary for enterprise SATA
  • Best dollar per gigabyte advantage within enterprise-class hard drives
  • Rated for 24-hour by 7-days-a-week, 365-days-a-year operation
  • Enterprise SATA 3.5" MTBF at 1.2 million hours versus consumer 3.5" SATA at 550K hours MTBF
Dell's enterprise SATA solution, found in PowerEdge servers and PowerVault enclosures, is a SATA interface for hard drives featuring specific design and manufacturing processes enabling 24x7x365 operations and 1.2 million hours MTBF within an enterprise environment.
Why enterprise SATA over consumer SATA 
Enterprise SATA drives offer similar dollar-per-gigabyte advantages as consumer SATA for tier-2 storage while also providing key design and process enhancements to allow for successful integration with specific Dell RAID controllers as part of Dell’s server and storage solutions. Typical SATA drives commonly found in the consumer, desktop and notebook arena lack the design and reliability characteristics required for the more strenuous enterprise environment. These consumer (or client)-grade hard drives are typically rated at around 550K hours MTBF (mean time between failures) and not rated for 24x7x365 usage. While these consumer-grade drives are typically OK to utilize as boot devices, their capability to perform within the enterprise is limited. enterprise SATA drives are designed with reliability and compatibility in mind. Enterprise SATA drives are rated for 24x7x365 operation, have Dell developed and certified firmware to ensure compatibility within Dell servers and storage, and also are typically equipped with rotational vibration circuitry to allow for the adjacencies of multiple drives, servers and storage enclosures common within the enterprise.
Dell Update Package (DUP) support is now available on select enterprise SATA hard drives. DUP allows for hard drive firmware to be updated without taking down the storage subsystem. Less downtime means higher productivity.