Comings and goings - is flash the next optical?

Two contrasting stories caught my attention this morning:  Compellent's flash announcement and Howard Marks from Information Week discussing how enterprise optical storage is fading to black after so many years.

The juxtaposition forced the question: could flash - as the latest incarnation in a long line of silicon-based mass storage be another exciting storage idea that doesn't make it?  For the record, I think solid state disk (SSD) enterprise storage will succeed.  EMC's Storage Anarchist wrote about the industry's efforts to get flash SSDs over the hump last month - its a good read. 

Whether flash will be the SSD technology of choice over the long haul is another story, but more on that some other time.

First: a comparison of enterprise optical and flash:

• Enterprise optical was primarily used as a replacement for tape and used for backup and archive - it was/is removable media.  Flash SSDs are primary storage.  It can be removable, but is being applied to replace  high-RPM disk drives.
  
• Enterprise optical performance did not compare well against streaming tape performance.  Optical, like flash, is fast to read and relatively slow to write.  The problem is, as a tape replacement, optical was used 99% of the time for writes. Flash has performance advantages for read-intensive applications but no advantage over high-RPM disk drives for write-intensive applications.
  
• Enterprise optical capacities did not compare well against tape. Its not clear what the capacity requirements are for flash SSDs, but they are sufficient to replace high-RPM disk drives (with their associated smaller capacities). 
  
• Enterprise optical was somewhat more expensive than contemporary tape equipment. The cost of flash is typically much higher than similarly-sized high-rpm disk drives.
  
• Enterprise optical was not integrated as a component with existing disk or tape systems  Flash SSDs (today) are being offered as integrated features of existing product lines.
  
• Enterprise optical was anticipated to be more reliable than tape, but it did not establish a track record to prove it.  Flash, with less moving parts would appear to be more reliable than disk, but there are still questions about cell wear out.  Reliability reputations take time and flash SSDs haven't been around long enough to have much of a reputation one way the other. 

My opinion is that the near term issue for flash SSDs is whether it can scale to sufficient capacities to satisfy read-intensive applications such as data mining.  It the near term, it will be relatively expensive, but the cost can probably be justified by some customers.  However, if it is not capable of scaling, that could be a serious problem.

Longer term, the technology has to be more closely coupled with existing storage, including making flash more "invisible" through virtual storage techniques. 

Comments

[Martin G]

Enterprise SSDs are genuinely fixing a problem which the current technology level can't fix and I can't see them ever being able to fix. You can only spin a disk so fast, so we need something new to fix some of the problems we have; looking the modelling for some of the applications we have coming down the line; if we do it on spinning rust, we need 1400 spindles for the primary disk excluding Snaps, Clones etc; SSDs might actually be an answer.

Optical technology unfortunately was a stop-gap and tape caught up, negating the need for optical in the enterprise generally. I don't think this will happen for SSDs.

[Pete Steege]

Nice post Marc. Cost and perceived & real reliability will be key issues near-term.

The close coupling with existing storage happens as disk drive vendors like Seagate make flash media into a true enterprise device, just as they've done for spinning media. Different techniques, same result.