2011: Year of the SSD?

Disk manufacturers are putting a new spin on an old product: Solid State Drives. New technology, increased power costs, space limitation, and new business requirements are driving advances in storage. Solid State Drives (SSDs) are part of that new technological push toward more efficiency, increased agility, and higher demand.

EMC reports that it shipped more than 10 petabytes (PB) of SSD capacity last year. Were you the proud recipient of some of these new high-speed, non-mechanical disks? If you purchased any blade systems in the last 18 months, it's likely that you were.

SSDs rival SATA (Serial ATA) drive capacity and exceed their performance by several times and life expectancy by decades. Advocates of SSDs say the storage-related monikers of yesteryear will leave for good when we learn to embrace the new solid-state (non-mechanical) drives and their associated terminology - that terms like 'disk' and 'drive' will be be replaced by 'space' and 'storage.'

Life Expectancy

It seems every new technology is viewed as a panacea for the problems that have plagued us since the technology revolution began. Television was supposed to make radio obsolete, and computers were supposed to make people's lives so much easier. Has your life gotten easier? More interesting perhaps, but not necessarily easier.

One of the selling points for SSDs is their extended life expectancy. And it isn't a year or two beyond that of conventional disk technology; it's on the order of 10 times longer. One estimate puts the life expectancy of SSDs at 50 years.

If that estimate is close to being accurate, that would be a major breakthrough for long-term archival storage. But, as we remember back to the introduction of optical media (CD and DVD), we find that these estimates often fall significantly short of their original targets. The reality is that no one knows for sure how long data will last on these media. No one knows data degradation rates or any real method of their calculation. Estimates are based on guesses and not on reality.

Expect SSDs to last for several years and transfer your data from them to the new technology that will replace them for safe keeping. The best advice is to distort Rudyard Kipling's words about trusting men by saying, "Trust all media, but none too much."

Write Endurance

One of the big myths and major barriers to SSD adoption is the myth of low write endurance. Write endurance is the number of write cycles to a block of flash memory. This implies that writing larger chunks of information to your SSDs sustains them better than writing millions of small chunks. The fear is that over time SSDs will become unrealiable due to the limited number of write cycles per block.

Unfortunately, only time will tell on this suspected SSD limitation. SSDs haven't been used in sustained production long enough to make accurate predictions. But manufacturers assure us that new SSDs have built-in wear-leveling techniques and error correction software that negates claims alleging that SSDs don't have the opportunity for a long life due to write endurance problems.

Cost

SSDs are expensive. Really expensive. However, their life expectancy, lower power requirements, and low failure rate makes their cost comparable to equal capacity mechanical drives. Costs of SSDs will fall over time as supply and technology catches up to demand. Remember when the first DVD players hit the market at more than $1,000? Now they're so inexpensive that they're basically throw-away items. All technology products follow this same path.

A Mixed Storage Bag

Besides performance, SSDs can be mixed with other types of drives so that data can be segregated based on usage requirements. For example, active data will remain on SSDs to take advantage of the higher performance, while inactive data will stay on less expensive and slower SATA drives. The non-cost advantage of this scenario is that SSDs and other types of drives can be mixed in SANs. That's right, SSDs aren't just for local storage anymore.

As you can see, there are many advantages to using SSDs in your data center. The primary drawback to SSDs is their hefty price tag.  The SSD snowball is rolling and picking up momentum.