Proprietary SAN/NAS boxes cannot be commodity by design because they are still produced with much lower amount compared to ordinary servers. Going with non-commodity means accepting a few negative aspects:
- High cost: Since proprietary hardware based storage systems are not mass-produced, the “economy of scale” never kicks in, so the price of the resulting solution goes through the roof. Moreover, quite often non-commodity boxes have expensive "magic hardware" (NVRAM, ASICs, custom IO processors, etc.), further driving your expenses through the roof.
Going non-commodity typically means a longer generation life cycle.
While new generations of proprietary hardware are developing 4-5 years, the commodity boxes are renewing every 1-2 years. Thus, for two years of deployment commodity servers will evolve: physical disks and RAM capacity, CPUs with more cores and higher frequency, high-speed multi-port NIC, etc. while the proprietary box will remain the same. As the result, the user gets less performance for a bigger cost when going non-commodity.
- Hardware maintenance is an issue when talking about non-commodity. Getting a new replacement of baked IO controller from vendor can take weeks or even more.
- Another big thing is using off-the-shelf storage components like hard disks and flash memory. High-end storage systems do not accept common off-the-shelf hard drives and flash memory, they use only rebadged ones by vendor with modified firmware. Thus, there is no way to buy them from anybody but the storage vendor directly. Going with rebadged components is by order of magnitude more expensive comparing to ordinary ones. The vendor may just stop developing certain hardware, so when the time comes - nothing is there to replace the old hardware with.
- Non-commodity cannot be re-provisioned. EOLed storage system can serve as the SAN or NAS only, nothing else since firmware that allows using it for another purpose don`t exist after it will reach EOL.