Two Downsides of Using RAID for Storage in SMBs

Paul Mah
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Changing the Way You Purchase Storage

Ensure that IT has the flexibility to build and efficiently run a shared infrastructure.

When it comes to data storage and backup, SMBs are likely to have heard about RAID, or are at least aware of its existence. In a nutshell, RAID technology offers redundancy against data loss should hard disk drives (HDDs) fail. This is achieved by employing strategies that include mirroring of data on a separate hard disk drive (HDD) or spreading it across a predefined number of HDDs using a technique called data striping. Indeed, it would be unusual to see an NAS device that does not support a few RAID configurations at a minimum. If you're not already familiar with RAID, you can read about the most common RAID levels here.


A recent article contributed by storage vendor Drobo on Computer Technology Review briefly talked about why SMBs have a "love/hate relationship" with RAID, highlighting its relative complexity for the average small business owner. Obviously, it is in Drobo's interest to talk down other storage technologies in order to draw attention to its BeyondRAID technology, which is implemented in the company's range of networked and direct attached storage appliances. The article got me thinking, however, and I want to bring your attention to two weaknesses of RAID systems today.


No seamless capacity expansion


The desired RAID level is selected upon creation, which effectively determines the total usable space for a particular "array." Upping one's current storage capacity entails the removal of an existing array, adding in the new hard disk drives and recreating of the new array based on the desired RAID level. It goes without saying that important data must be manually backed up and restored, which, depending on one's exact configuration, may be a time-consuming activity or even necessitate taking the storage system offline.


The less-obvious problem here would be when businesses find themselves outgrowing their storage space. So, while upgrading a RAID array with more HDDs is hardly rocket science, it does require some advanced planning and setup - tasks that some SMBs may find themselves stumped by. In addition, backing up existing data to a secondary storage device may also be error-prone, and any mistakes could have disastrous implications.


Inflexibility in terms of failed HDD replacements


Another weakness of RAID systems can be evidenced when a HDD fails. The conventional advice given to storage administrators is to use only HDDs of the same model and capacity in a RAID array. The cautious SMB would hence splurge additional money on replacement HDDs even before they are needed, or simply keep their fingers crossed and hope that replacements will still be available for purchase when their existing disk drives fail.


While SMBs can certainly opt to replace all the disk drives should it prove difficult to obtain the same HDD as a replacement, having to do it at short order may lead to much anxiety. And depending on the RAID level used, this may also result in degraded or non-existent data protection in the interim.




My objective today is to highlight two downsides of RAID, and show that it is not a perfect storage technology. Having said that, I want to stress that the above disadvantages do not equate to flaws; RAID has certainly worked well for many businesses over the years.


Moreover, the popularity of RAID means it is well understood, with a corresponding larger pool of administrators capable of managing such systems. Moving on, I may write about alternative storage systems such as Drobo's BeyondRAID, Synology's Hybrid RAID (SHR) and others if there is sufficient interest. In the meantime, feel free to pen your thoughts about RAID in the comments section below.

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