Posted on by greg

RAID Relevance Revisited

Following up from some previous posts on the topic, a continued discussion point in the data storage industry is the relevance (or lack there) of RAID (Redundant Array of Independent Disks).

These discussions tend to evolve around how RAID is dead due to its lack of real or perceived ability to continue scaling in terms of performance, availability, capacity, economies or energy capabilities needed or when compared to those of newer techniques, technologies or products.

RAID Relevance

While there are many new and evolving approaches to protecting data in addition to maintaining availability or accessibility to information, RAID despite the fan fare is far from being dead at least on the technology front.

Sure, there are issues or challenges that require continued investing in RAID as has been the case over the past 20 years; however those will also be addressed on a go forward basis via continued innovation and evolution along with riding technology improvement curves.

Now from a marketing standpoint, ok, I can see where the RAID story is dead, boring, and something new and shiny is needed, or, at least change the pitch to sound like something new.

Consequently, when being long in the tooth and with some of the fore mentioned items among others, older technologies that may be boring or lack sizzle or marketing dollars can and often are declared dead on the buzzword bingo circuit. After all, how long now has the industry trade group RAID Advisory Board (RAB) been missing in action, retired, spun down, archived or ILMed?

RAID remains relevant because like other dead or zombie technologies it has reached the plateau of productivity and profitability. That success is also something that emerging technologies envy as their future domain and thus a classic marketing move is to declare the incumbent dead.

The reality is that RAID in all of its various instances from hardware to software, standard to non-standard with extensions is very much alive from the largest enterprise to the SMB to the SOHO down into consumer products and all points in between.

Now candidly, like any technology that is about 20 years old if not older after all, the disk drive is over 50 years old and been declared dead for how long now?.RAID in some ways is long in the tooth and there are certainly issues to be addressed as have been taken care of in the past. Some of these include the overhead of rebuilding large capacity 1TB, 2TB and even larger disk drives in the not so distant future.

There are also issues pertaining to distributed data protection in support of cloud, virtualized or other solutions that need to be addressed. In fact, go way way back to when RAID appeared commercially on the scene in the late 80s and one of the value propositions among others was to address the reliability of emerging large capacity multi MByte sized SCSI disk drives. It seems almost laughable today that when a decade later, when the 1GB disk drives appeared in the market back in the 90s that there was renewed concern about RAID and disk drive rebuild times.

Rest assured, I think that there is a need and plenty of room for continued innovate evolution around RAID related technologies and their associated storage systems or packaging on a go forward basis.

What I find interesting is that some of the issues facing RAID today are similar to those of a decade ago for example having to deal with large capacity disk drive rebuild, distributed data protecting and availability, performance, ease of use and so the list goes.

However what happened was that vendors continued to innovate both in terms of basic performance accelerated rebuild rates with improvements to rebuild algorithms, leveraged faster processors, busses and other techniques. In addition, vendors continued to innovate in terms of new functionality including adopting RAID 6 which for the better part of a decade outside of a few niche vendors languished as one of those future technologies that probably nobody would ever adopt, however we know that to be different now and for the past several years. RAID 6 is one of those areas where vendors who do not have it are either adding it, enhancing it, or telling you why you do not need it or why it is no good for you.

An example of how RAID 6 is being enhanced is boosting performance on normal read and write operations along with acceleration of performance during disk rebuild. Also tied to RAID 6 and disk drive rebuild are improvements in controller design to detect and proactively make repairs on the fly to minimize or eliminate errors or diminished the need for drive rebuilds, similar to what was done in previous generations. Lets also not forget the improvements in disk drives boosting performance, availability, capacity and energy improvements over time.

Funny how these and other enhancements are similar to those made to RAID controllers hardware and software fine tuning them in the early to mid 2000s in support for high capacity SATA disk drives that had different RAS characteristics of higher performance lower capacity enterprise drives.

Here is my point.

RAID to some may be dead while others continue to rely on it. Meanwhile others are working on enhancing technologies for future generations of storage systems and application requirements. Thus in different shapes, forms, configurations, feature; functionality or packaging, the spirit of RAID is very much alive and well remaining relevant.

Regardless of if a solution using two or three disk mirroring for availability, or RAID 0 fast SSD or SAS or FC disks in a stripe configuration for performance with data protection via rapid restoration from some other low cost medium (perhaps RAID 6 or tape), or perhaps single, dual or triple parity protection, or if using small block or multiMByte or volume based chunklets, let alone if it is hardware or software based, local or disturbed, standard or non standard, chances are there is some theme of RAID involved.

Granted, you do not have to call it RAID if you prefer!

As a closing thought, if RAID were no longer relevant, than why do the post RAID, next generation, life beyond RAID or whatever you prefer to call them technologies need to tie themselves to the themes of RAID? Simple, RAID is still relevant in some shape or form to different audiences as well as it is a great way of stimulating discussion or debate in a constantly evolving industry.

BTW, Im still waiting for the revolutionary piece of hardware that does not require software, and the software that does not require hardware and that includes playing games with server less servers using hypervisors :) .

Provide your perspective on RAID and its relevance in the following poll.

Here are some additional related and relevant RAID links of interests:

Stay tuned for more about RAIDs relevance as I dont think we have heard the last on this.

Ok, nuff said.

Cheers gs

Greg Schulz – Author Cloud and Virtual Data Storage Networking (CRC Press), The Green and Virtual Data Center (CRC Press) and Resilient Storage Networks (Elsevier)
twitter @storageio

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