Hot swappable drive bay cases

​Why do you need a ​ho​t swappable drive bay case?

In today's world of exponential data growth, digital storage space always seems to be in short supply. This is most often true in the home where technical resources are usually more limited. Add to that the rise in prevalence of the Solid State Drive (SSD), a more expensive technology than the traditional Hard Disk Drive (HDD) meaning smaller storage drives for the same price, and the amount of free digital storage space available to the home user is at constant risk of being overwhelmed.

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More and more drives

One way to keep up with this ever-expanding need for disk space is to keep buying more and larger external storage drives. However, a number of problems arise with this strategy, most notably with the power supplies that come with each new storage device purchase. Homes have a limited number of power sockets so constantly adding more storage drives each with their own power-plug requirements presents an obvious problem. In addition, in the interests of fire safety, adding more and more power plugs to a multi-plug adapter is also not a good idea, as at some point, you will begin exceeding the rated amperage for the multi-plug adapter, resulting in the blowing of a fuse, the triggering of a circuit breaker, or worse, the starting of a fire!

​More ​hard drives means more wiring

​Adding more individual digital storage ​drives also means adding more and more wiring to the home computing set-up, both for the power requirements and for the data connection to the computer. This can get messy very quickly and can be a nightmare to keep organised. In addition, computers have a limited number of data ports, so adding more individual external drives usually means either fumbling around at the back of the computer unplugging and plugging in the correct data connections for different hard drives, or using a separate data connection hub, which​ can mean another power supply and yet more wiring!

​Recycling old laptop and desktop drives

Most of us change our laptop and desktop computers every few years, as their processing power becomes outdated and unable to keep up with today's computing environment. However, the hard drives or solid state drives inside these machines are often still very much in their prime. As a result, it is becoming increasingly common these days to pop the HDD or SSD out of the old computer and purchase an enclosure for the drive in order to convert it into an external storage drive. This works fine initially but over a multitude of years leads to having a collection of external hard drives, once again each with their own wiring and port requirements.  

The multi-bay hard drive enclosure

​A clever solution to the problem of 'external hard drive-overload syndrome' is the multi-bay hard drive enclosure. Multi-bay hard drive enclosures for the home user come in all shapes and sizes, housing anywhere from 2 hard drives or SSDs up to 10 of them in the 10 ​bay hard drive enclosure. They usually comprise of a desktop case with hot swap drive bays and usually ​run off a single data connection to the computer ​as well as a single power supply, so alleviate many of the typical issues of having too many individual hard drives. So what should one look for in a multi-bay hard drive enclosure? Let's take a look.

​What to look for in a multi-bay hard drive enclosure

​The 8-bay hot swap chassis

​There are a few things to consider before taking the plunge and buying your first multi-bay hard drive enclosure. First and foremost amongst them is the ​number of drives the enclosure can ​accommodate. We at Desktopvibes.com ​favour the 8-bay and above hot swappable drive bay case as most of us already have several spare hard drives ​from old laptops ​lying around, with more on the way ​from current computer tech ​that is on the road to obsolescence. ​As a consequence, we focus here on these bigger capacity enclosures, but many of the same principles can be applied to enclosures with fewer hard drive bays if ​those ​happen to suit your needs better.

Drive size

​The standard size for laptop hard disks drives and solid state drives ​is the 2.5" drive. For desktop computers, it is a 3.5" drive, which usually ​has more ​storage capacity due to ​its bigger physical size and less expensive per gigabyte storage space. So if you are buying extra HDD or SSD storage, the preference is for 3.5" drives since you get more bang for your buck. Fortunately, the majority of multi-bay hard drive enclosures primarily accommodate 3.5" drives, however, we still would like it to handle 2.5" drives as well in order ​to breathe new life into our ​old laptop drives. Only some multi-bay enclosures ​have been designed to handle 2.5" drives natively in addition to the 3.5" ones​. For others, a special adapter tray can ​often be purchased separately that holds ​a 2.5" drive ​while fitting into the 3.5" bay of the enclosure.

JBOD vs RAID vs Large

​What is JBOD, and how does it differ from RAID or a Large configuration? This is probably the most fundamental question when it comes to setting up your new multi-bay hard drive enclosure, and it will almost completely depend on your needs with regards to hard drive back ups and resilience against data loss. I​n addition, knowing the configuration ​that you intend to use your multi-bay enclosure in is an important pre-purchase ​criterion, as each multi-bay enclosure comes with a different range of configurations to which ​it can be set. ​So what are these configurations?

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    ​​JBOD or 'Just a Bunch Of Disks' is a configuration where each HDD or SSD in the enclosure's ​array appears as a separate drive. In other words, if you have ​8 hard drives within ​an ​8-bay hot swap case, then you will see 8 individual hard drive icons on the computer's desktop when it is powered up.
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    ​RAID or 'Redundant Array of Independent Disks' consists of a range of configurations, each represented by a different number, where all the available hard drives are virtually ​combined ​to form a storage space with various levels of data redundancy. Depending on the RAID configuration, this can be useful for both protecting data against hard drive failure, as well as for increasing hard drive read / write performance. Unfortunately, with a RAID configuration, you invariably lose some of ​the total capacity of storage space, with the specific amount depending on the RAID configuration chosen.
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    ​A Large or Big configuration is a bit like the JBOD ​set-up above, however, all the drives are virtually combined to form a single large storage space. This set-up is not unlike some RAID configurations but without any consideration for data protection and redundancy or drive performance. In other words, if you had 10 hard drives in the enclosure, the total hard drive storage space would be the sum total of all of the individual hard drives ​​and ​this would all be represented by a single icon on the desktop.

SATA ​vs SAS

​​Hard drives and SSDs ​are designed to connect internally to computing hardware via one of a number of ports. The most prevalent of these internal connections is the SATA port, which is particularly common amongst consumer hardware. The SATA port has been around for quite some time and over the years has progressed through three different iterations, ​SATA I, SATA II, and SATA III, with each version doubling the theoretical maximum data transfer speed over the previous version. An alternative to SATA is the Serial Attached SCSI (SAS) port which is more commonly found in hardware designed for ​servers. ​It too has developed over the years with its latest iteration, SAS-4, able to transfer data at a whopping 22.5 Gbps. SAS is superior to SATA in several ways but it is also generally more expensive. The main differences between SATA and SAS are as follows:  

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    ​SAS hard drives can rotate much faster then SATA drives, so read / write performance is better
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    ​SAS hardware can read and write simultaneously while SATA can only do one at a time
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    ​SAS hard drives last longer than SATA drives
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    ​SAS cables can be much longer than SATA ones
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    ​SAS is in general a more expensive technology than SATA hardware

SATA I

​1.5 Gbps

SATA II

​3 Gbps

SATA III

6 Gbps

​SAS-1

​3 Gbps

​SAS-2

6 Gbps

​SAS-3

​12 Gbps

​SAS-4

​22.5 Gbps

​Consequently, SAS hardware tends to be the preferred technology for more professional applications, ​but is ​viewed as 'overkill' for consumer applications, this is why most products available to home users are SATA-based hardware. This is also the case for consumer-focused multi-bay hard drive enclosures with the internal connections to the ​hard drives most often via SATA. However, an important ​criteria to watch out for when choosing a multi-bay HDD enclosure ​is the SATA iteration the hard drive case supports, ​as some were designed to run data only at SATA II speeds (although still compatible with SATA III drives).

​​USB 3.0 vs eSATA

​Now that we have the hard drives and SSDs connected to the multi-bay enclosure, the only question remains is how is the hard drive enclosure itself connected to the computer. There are two main methods through which this connection is most often facilitated: USB and eSATA. ​The USB standard has evolved over ​a couple of decades and is currently within its third iteration, USB 3. ​As of this writing, the most common form is USB 3.0 with a maximum data transfer rate of 5 Gbps, ​which is currently found on the majority of multi-bay HDD enclosures. ​There is a more recent​ USB standard, USB 3.1, which sees the doubling of this data rate to 10 Gbps, however, this is ​not yet commonly present on multi-bay HDD enclosure hardware, and may even be considered unnecessary on SATA-based hardware since the data transfer rate ​is anyway limited to the 6 Gbps ​​maximum of internal SATA III ​connections. ​

​USB 1.1

​0.012 Gbps

​USB 2.0

​0.48 Gbps

USB 3.0

5 Gbps

USB 3.1

​10 Gbps

An eSATA port is also found on many multi-bay hard drive enclosures ​and is equivalent to the internal SATA connections of the device but designed for external cable ​use. The eSATA port on the multi-bay hard drive enclosure is not as frequently used as the USB port since eSATA ports are not often included on computing hardware for the consumer. In addition, to use eSATA on ​a multi-bay HDD case, a component known as a 'Port Multiplier' needs to be incorporated either within the HDD enclosure itself or within the computing hardware, whereas with USB​, ​port multipliers are unnecessary.

​UASP

​UASP or USB Attached SCSI Protocol is a protocol that speeds up USB data transfer​ getting it to come closer to ​its theoretical maximum data transfer speed, so for example in the case of USB 3.0, speeds will come closer to ​its 5 Gbps maximum. For UASP to work its magic, it needs to not only be supported within the multi-bay HDD enclosure itself, but it also needs to be supported within the computer and operating system ​as well. Fortunately, most modern computers and operating systems support UASP, ​including Mac OS 10.8 and above, Windows 8 and above, and Linux version 3.15 and above​, so it is a good idea to make sure the multi-bay enclosure you purchase also supports it.

​Popular external hard drive array storage towers

  No. of
HDD bays
HDD sizesModesHDD interface
(internal)
USB 3.0eSATAUASP
support
Sharkoon RAID station
82.5”
3.5”
JBOD^

RAID 0, 30, 50
SATA I & II **
Sans Digital TR8UT+
83.5"JBOD^

RAID 0, 30, 50
SATA I & II **
Fantec QB-X8US3 1465
83.5"Large (Big)

RAID 0, 5, 10, 50
SATA I & II **
StarTech S358BU33ERM
82.5”
3.5”
JBOD^SATA III *
Icy Box IB-3680SU3
83.5"JBOD^SATA III *
Icy Box IB-3810U3
103.5"JBOD^SATA III *
Fantec QB-X8US3 1696
83.5"JBOD^SATA III *
* Compatible with SATA I and SATA II drives

** Compatible with SATA III drives (but at the lower SATA specification speeds)

^ JBOD = "Just a Bunch Of Disks" - Each HDD appears as an individual drive

NB: USB 3.0 is backwards compatible with USB 2.0