Stephen Foskett, Pack Rat

Specialized Server/Enterprise Hard Drives

Posted on Aug 07, 2007 by Stephen

Continuing my overview of the specialized hard drive market, we move on to the world of enterprise hard disk drives. These are performance monsters, with nearly all falling above the 10,000 RPM line that defines “exotic” in the desktop space. They also have a wide variety of interfaces, including parallel and serial SCSI, Fibre Channel, and even SATA.

Lots of innovation is currently on the horizon in the enterprise drive space, notably the application of desktop and mobile technologies to the space. Right now, you can buy a 15,000 RPM 2.5″ dual-SAS enterprise mechanism from two different companies! Or maybe you want a 1 TB bulk drive with SATA? These are a far cry from the bread and butter 10- and 15k 3.5″ SCSI and FC drives we’ve long been accustomed to. Click through for the full story…

Segment Differentiators

The market for enterprise drives is quite different from the desktop world. Buyers are less price- and power-sensitive and much more concerned about raw performance.

Vendor claims of enhanced reliability have been questioned by many, but it cannot be doubted that these drives are often engineered differently. Seagate representatives told me that they focus on stronger casings to reduce flexing under stress of faster rotational speeds and increased heat. They also often use different bearing, airflow, and filter designs. And enterprise drives use lower-capacity platters. But objective studies have not revealed great reliability improvements.

Drive interfaces are quite different than other market segments. Although SATA and Serial -Attached SCSI (SAS) is becoming more common, the bulk of enterprise drive shipments use Ultra SCSI or Fibre Channel. State of the art is 3 Gb dual-SAS and 4 Gb FC, with parallel SCSI and especially 2 Gb FC becoming less common. We will soon begin seeing 6 Gb/s SAS, and multi-channel drives promise to multiply interface performance.

Spindle speed has long been the defining characteristic of enterprise drives. Back when 5400 (and even slower) ATA drives were common in desktops, enterprise arrays relied on 7200 and 10,000 RPM SCSI and Fibre Channel drives. These days, desktops have ratcheted up to 7200, and enterprise units have climbed to 15,000 RPM, with 10,000 RPM becoming the new standard. These speeds (7200, 10k, and 15k) are available across the board on all enterprise drives.

Emerging Trends

Two trends are particularly notable in the enterprise space: “Enterprise” brothers of high-performance desktop SATA drives, and 2.5″ form factor units.

All four current enterprise drive vendors offer high-capacity SATA drives in the enterprise market. Ranging in size to 1 TB, these drives are increasingly being deployed for tiered storage, disk-based backup, archiving, and other less performance-sensitive tasks. Paired with RAID-6, it is likely that the reliability of enterprise storage arrays using SATA drives will be satisfactory. Certainly their massive capacity will bring the per-GB price point down!

SATA in the enterprise has been controversial, but much of this has to do with the meager specifications of the SATA drives examined, rather than any limitation of the protocol itself. It must be pointed out that SATA and SAS share the same physical connectors and interface chips, and the introduction of command queueing (albeit a different implementation) across the board in the latest SATA drives means the interface could be appropriate for just about any use if paired to a fast-enough drive mechanism. I wonder if their opinions would change if they tested Western Digital’s 10,000 RPM Raptor instead of a 7200 RPM Hitachi or Seagate drive.

Undoubtedly, multi-channel and 6 Gb SAS will outperform SATA in the long run. And the implementation of command queueing, drive naming, and bus expansion in SAS remains superior. But SATA is plenty fast for many of today’s needs, especially when tiered storage is considered.

The other big trend is the introduction of 2.5″ enterprise drives. With ultra-fast 15,000 RPM 2.5″ enterprise drives now available from multiple vendors, this segment simply cannot be ignored. In fact, the fastest enterprise drive available today (by a slight margin) is a 2.5″ Seagate Savvio! Combine these amazing performance claims with the fact that more physical spindles can be packed into the same space and we have a winning combination for enterprise arrays! However, these ultra-dense 2.5″ arrays will also be ultra heavy, and paradoxically ultra hungry for power and cooling, since many more drives will be used, even though each drive is more efficient. This will lead to the same weird situation we now see with blade servers – where so much density is achieved that empty rack space must be preserved to keep weight, power, and cooling demands in check!

Specific Drive Offerings

There are a multitude of enterprise drives on the market, but many users have little say in what they get. Each vendor selects their own drives when it comes to enterprise storage arrays! But by examining the array of offerings, we can learn something about the market. More information is available in this Tom’s Hardware comparison table, which is updated regularly, as well as this Tom’s Hardware article.

Fujitsu

Fujitsu’s drive names can be perplexing, with dozens of different drives currently offered. Generally, though, you can figure them out with a bit of detective work. They use the second two letters in their naming scheme for drive families or generations – MAW is older than MAX, then comes MAY, MBA, and MBC. The number is the drive’s size – 3 for 3.5″ and 2 for 2.5″. The final two letters is the drive’s interface – NC or NP for parallel SCSI, RC for SAS, and FD for Fibre Channel.

Fujitsu focuses solely on the mobile and enterprise markets, and is joining most other vendors in the 2.5″ enterprise race. Let’s start with their 3.5″ units, though. Replacing the old 10,000 RPM MAW line is the MAX3, available in SCSI (NC/NP) or dual SAS (RC) and offering 36, 73, or 147 GB of capacity and 15,000 RPM. The MBA3 line is offered in 2 or 4 Gb FC (FD), SCSI (NC/NP), or dial SAS (RC) and boasts 73, 147, or 300 GB and 15,000 RPM.

The company has jumped into the 2.5″ form factor as well, which is no surprise given its line of mobile drives. The MAY2 RC was first, with dual SAS interfaces, 10,000 RPM speed, and 36 or 73 GB of capacity. This was upgraded to 73 or 147 GB with the similar MBB2 RC. Both boast 16 MB of cache. The new MBC2 RC, announced in May and available in 36 or 73 GB, is the stunner, though, with 15,000 RPM.

Hitachi

Hitachi’s naming focuses on drive speed – the 7K, 10K, and 15K names are easy enough to decode. Next is an indication of platter size and generation, which is much less specific. Larger numbers are generally newer and seem to refer to the flagship of that line. So the “300″ line tops out at 300 GB, the “147″ is older and smaller, and the “1000″ is the big up-to-1 TB SATA unit.

Hitachi’s enterprise credentials rest on traditional 3.5″ drives with Ultra SCSI and Fibre Channel interfaces. The 10K300 is the company’s entry level, with 10,000 RPM and capacities of 73, 147, and 300 GB. Although that drive boasts only SCSI and 2 Gb FC, the faster 15K147 adds 3 Gb SAS and 4 Gb FC, along with 15,000 RPM speeds.

Just introduced is Hitachi’s top-dog drive, the 15K300. Combining 15,000 RPM speed and 300 GB capacity in a 3.5″ enterprise drive is impressive, and 2 Gb FC is no longer offered.

Hitachi’s new entry-level enterprise model is the A7K1000. Based on the 7K1000 desktop SATA drives, this unit has 3 to 5 platters for 500 GB, 750 GB, or 1 TB capacity. The similarities might lead some to question this 7200 RPM SATA drive’s enterprise credentials, however.

Hitachi also just introduced a 2.5″ enterprise drive, the C10K147. With sizes of 73 and 147 GB, speeds of 10k RPM, and a SAS interface, there is little to differentiate this drive apart from its small size.

Seagate

Seagate’s entry-level line is the Barracuda ES. Now in its second generation (the ES.2), this line is an uprated Barracuda SATA drive with optional dual-port SAS for enterprise applications. Running at 7200 RPM like its desktop brother, the ES line reaches 1 TB.

Seagate’s mainstream enterprise offering is the Cheetah line. The seventh-generation 10K.7 is the 10,000 RPM traditionalist, in 73, 146, and 300 GB capacities and Ultra SCSI and 2 Gb FC interfaces. The 15K.4 offers 36, 73, and 146 GB capacities, 15,000 RPM performance, and adds 3 Gb SAS as an option.

Seagate’s performance leader is the perpendicular-recording 15K.5. The company boasts 100 MB/s sustained throughput from this modern 73, 146, or 300 GB 15,000 RPM drive. 4 Gb FC, 3 Gb SAS, and Ultra SCSI are all offered. A variant of the 15K.5 is the Cheetah NS. Available in 300 GB and 400 GB sizes and 4 Gb FC or 3 Gb SAS, Seagate claims power optimization benefits in addition to best-in-class capacity.

Seagate entered the 2.5″ enterprise drive market back in 2004 with the Savvio line. The 36 or 73 GB 10K.1 was upgraded in 2006 to 73 or 146 GB in the 10K.1 line. But the real winner is the 15,000 RPM Savvio 15K announced in January. This 36 or 73 GB drive is easily the highest-performance 2.5″ on the market, boasting impressive 104 MB/s throughput numbers.

Western Digital

Western Digital trails the pack, offering no 15,000 RPM, FC, or SCSI drives at all. They do boast the world’s only 10,000 RPM SATA drive, the Raptor, as well as a decent-sized 750 GB SATA unit in their RE2 line. I’m looking forward to their future offerings, especially if Green Power is included (as expected).

Conclusion

The arena of enterprise hard drives is perhaps the most interesting in the entire market. Combine the twin impacts of large, slow 3.5″ drives and tiny, fast 2.5″ drives and we will soon see the market split along tiered storage lines. Although simply re-driving a storage array might not make it greener, tiered storage will reduce the average cost and increase the specific performance of enterprise arrays.

Some specific things that excite me in this space:

• The amazing 15k RPM 2.5″ drives from Seagate and Fujitsu give just the right amount of capacity and performance in a tiny form factor. These are perfect for servers and storage arrays alike. I expect Hitachi to come along with a similar drive soon, and I wouldn’t be surprised if laptop-king Toshiba joins in, too.
• Western Digital’s entry into the enterprise space won’t work without OEM wins, but their 10k RPM Raptor drives should prove enticing. I’d expect to start seeing these in tier-2 servers soon, but don’t look for them in enterprise storage arrays, at least not in this generation of hardware.
• The exit of Ultra SCSI is all but assured. Farewell, 68-pin connectors!
• SAS promises to finally offer the front-end connectivity demanded by today’s large, fast drives.

Tomorrow we’ll be looking at laptop and mobile drives. See you then!

Tags: disk drives, Fibre Channel, Fujitsu, Hitachi, Maxtor, OEM, Seagate, tiered storage, Toshiba, Western Digital