Is MAID Storage Dead? I Dont Think So!

December 8, 2009 – 2:08 am

Some vendors are doing better than others and first generation MAID (Massive or monolithic Array of Idle Disks) might be dead or about to be deceased, spun down or put into a long term sleep mode, it is safe to say that second generation MAID (e.g. MAID 2.0) also known as intelligent power management (IPM) is alive and doing well.

In fact, IPM is not unique to disk storage or disk drives as it is also a technique found in current generation of processors such as those from Intel (e.g. Nehalem) and others.

Other names for IPM include adaptive voltage scaling (AVS), adaptive voltage scaling optimized (AVSO) and adaptive power management (APM) among others.

The basic concept is to vary the amount of power being used to the amount of work and service level needed at a point in time and on a granular basis.

For example, first generation MAID or drive spin down as deployed by vendors such as Copan, which is rumored to be in the process of being spun down as a company (see blog post by a former Copan employee) were binary. That is, a disk drive was either on or off, and, that the granularity was the entire storage system. In the case of Copan, the granularly was that a maximum of 25% of the disks could ever be spun up at any point in time. As a point of reference, when I ask IT customers why they dont use MAID or IPM enabled technology they commonly site concerns about performance, or more importantly, the perception of bad performance.

CPU chips have been taking the lead with the ability to vary the voltage and clock speed, enabling or disabling electronic circuitry to align with amount of work needing to be done at a point in time. This more granular approach allows the CPU to run at faster rates when needed, slower rates when possible to conserve energy (here, here and here).

A common example is a laptop with technology such as speed step, or battery stretch saving modes. Disk drives have been following this approach by being able to vary their power usage by adjusting to different spin speeds along with enabling or disabling electronic circuitry.

On a granular basis, second generation MAID with IPM enabled technology can be done on a LUN or volume group basis across different RAID levels and types of disk drives depending on specific vendor implementation. Some examples of vendors implementing various forms of IPM for second generation MAID to name a few include Adaptec, EMC, Fujitsu Eternus, HDS (AMS), HGST (disk drives), Nexsan and Xyratex among many others.

Something else that is taking place in the industry seems to be vendors shying away from using the term MAID as there is some stigma associated with performance issues of some first generation products.

This is not all that different than what took place about 15 years ago or so when the first purpose built monolithic RAID arrays appeared on the market. Products such as the SF2 aka South San Francisco Forklift company product called Failsafe (here and here) which was bought by MTI with patents later sold to EMC.

Failsafe, or what many at DEC referred to as Fail Some was a large refrigerator sized device with 5.25” disk drives configured as RAID5 with dedicated hot spare disk drives. Thus its performance was ok for the time doing random reads, however writes in the pre write back cache RAID5 days was less than spectacular.

Failsafe and other early RAID (and here) implementations received a black eye from some due to performance, availability and other issues until best practices and additional enhancements such as multiple RAID levels appeared along with cache in follow on products.

What that trip down memory (or nightmare) lane has to do with MAID and particularly first generation products that did their part to help establish new technology is that they also gave way to second, third, fourth, fifth, sixth and beyond generations of RAID products.

The same can be expected as we are seeing with more vendors jumping in on the second generation of MAID also known as drive spin down with more in the wings.

Consequently, dont judge MAID based solely on the first generation products which could be thought of as advanced technology production proof of concept solutions that will have paved the way for follow up future solutions.

Just like RAID has become so ubiquitous it has been declared dead making it another zombie technology (dead however still being developed, produced, bought and put to use), follow on IPM enabled generations of technology will be more transparent. That is, similar to finding multiple RAID levels in most storage, look for IPM features including variable drive speeds, power setting and performance options on a go forward basis. These newer solutions may not carry the MAID name, however the sprit and function of intelligent power management without performance compromise does live on.

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)

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