A basic hard drive and a couple of flash drives is a suitable storage plan for the average PC user. The average business, on the other hand, needs more. More capacity. More efficiency, more reliability. Many businesses narrow their choices for enterprise storage down to two options: JBOD and RAID. Both have been covered here in the Recovery Zone, but we’ll do a brief overview to set the tone for our comparison: JBOD vs RAID.
The JBOD architecture is summed up perfectly by its acronym – Just a Bunch of Disks. If you’re envisioning a collection of regular ole hard drives strung together, your imagination has not failed you. The disks in a JBOD array can function as their own individual volumes or can be connected or spanned, to form a single logical volume. When it comes to expanding server storage capacity, few options are easier to implement than JBOD.
Redundant Array of Independent Disks or RAID, also lives up to its name by using various methods to create data redundancy. Rather than store data on a single disk, RAID breaks it down into smaller bits. These bits are replicated then distributed across multiple drives. The data is retrieved from this collection of drives whenever you need to access a file. Although widely viewed as an enterprise solution, RAID can be advantageous to just about any computer user.
Compare and Contrast
While there are similarities, JBOD and RAID are much more different than they are alike. Below we examine some of the key differences that set them apart:
Capacity utilization is arguably where JBOD shines the brightest. Whereas RAID typically allocates space for storing redundant data, JBOD utilizes the full capacity on each individual drive. So for instance, A JBOD configuration comprised of four 260 GB drives will provide a total of 1040 GB of usable space. In a digital universe where we are accumulating more data than we can comfortably handle, this could be a huge plus for organizations that realize every bit of storage counts.
In most cases, RAID outclasses JBOD in the performance department by a wide mile. RAID 0, for instance, increases the speed of both read and write operations by using multiple disks to make up for the limitations of one. In fact, all RAID configurations improve performance in one way or another. JBOD, by comparison, can potentially have a negative impact on performance as the system must process each disk successively.
Redundancy and Availability
One of RAID’s most well known benefits is providing an added layer of protection for servers and storage devices. RAID 0 is actually the only level that does not offer some degree of fault tolerance, a critical feature that allows a system to continually run without data loss or downtime in the event that the original system fails. While JBOD can provide redundancy for components such as power supplies and cooling fans, there is none at the disk level. What this essentially means is that if a disk in an array fails, you will lose any data that does not have a backup.
You can expand both JBOD and RAID for storage capacity, performance, and reliability. Expanding JBOD is usually as simple as adding another drive to the box. You can also use drives of various sizes so there’s a little more flexibility. Scaling out a RAID system is a bit more complicated. The pool of drives is a single entity that requires each drive to be the same size and model type. In either case, expanding storage arrays will call for administrators to take the number of additional drives needed, the size of those drives, and connectivity options under consideration.
In general, a JBOD architecture is significantly cheaper to implement than a RAID-based system. JBOD enclosures can be populated with SATA drives and controllers that are far less expensive than the SAS and SSCI hardware commonly used in RAID configurations. Expansion options for JBOD are equally affordable. This enables you to incorporate enterprise functionality at a greater dollar value than what RAID typically offers.
When to Use RAID
RAID is a tried and true storage option with an “array” of beneficial uses. Of course there are different configurations for different scenarios. For example, RAID 0 is ideal when you need a storage solution that is easy to implement and makes the most of your disk space. This is the one RAID configuration with no overhead so you get the benefit of maximum storage capacity. RAID 1 might be a sound option when you need high-performance and availability. This level could prove handy for an accounting firm that needs to maximize uptime for mission-critical IT systems, or even a home-based user looking to bulletproof the storage capacity on their PC.
When to Use JBOD … or Not
Identifying ideal JBOD use cases is a tad more complicated because well – some IT professionals will actually recommend against it. Here are three reasons why:
1. Scalability Limitations: While generally straightforward from a technical standpoint, physically expanding a JBOD setup is not always so cut and dried. The typical JBOD arrangement sees all drives housed in a single closure. Once it is full, adding to it can be a grueling process – and a costly one, too. So even though JBOD appears primed for big data applications, these sort of limitations have essentially capped its potential.
2. Management Complexity: Speaking of expansion, JBOD architectures become more challenging to manage the more enclosures you add to the mix. An IT administrator would need to manage a separate interface for each additional enclosure added to the system. The result is a storage management solution that requires more cost, effort, and time to keep under wraps.
3. Data Protection: As we alluded to earlier, all RAID systems beyond RAID 0 offer some form of data protection. Conversely, the lack of built-in data protection makes JBOD a risky storage proposition for mission-critical systems as the potential for data loss is much higher when compared to RAID. Questionable reliability is one of the biggest reasons companies are increasingly moving away from JBOD.
With everything it lacks, I see JBOD being useful in one scenario and one scenario only: when you need a cheap and relatively easy way to incorporate generous storage capacity, but disk failure is something you can live with – better yet, something you’ve planned for. Just in case. Until JBOD gets dramatic improvements on manageability and redundancy, it will continue to be the poor man’s RAID.
JBOD and RAID both have their merits as high-capacity storage options. But even with its long history of proven reliability, not even RAID is sufficient enough to replace a good backup plan. Instead of alternatives, both should be viewed as complementary cogs in a comprehensive business continuity strategy.