Most PC system cases are designed, well, under the assumption that they will be used
for regular PCs. Typically, space is provided within the case for one, two, or maybe three
hard drives. Sometimes there will be enough space for four or more, and you can also
"make space" by using drive bay
adapters. A regular PC case can therefore be satisfactory for small RAID arrays of 2,
3 or 4 drives, and certainly this is the least expensive option. This is often how
low-end, IDE/ATA RAID is done.
For "serious RAID" using many drives and the SCSI interface however, this
sort of arrangement is not really acceptable. More drives are often needed, and in
particular, drive swapping has become an important feature
that most high-end RAID users insist upon. To enable hot swapping and large numbers of
drives, you must look beyond regular PC cases.
One way to enable RAID and features such as hot swapping is to use a case specifically
designed for servers; you can see a picture of one below. Note the drive bays on both cases; the
large number of spaces for drives is specifically intended for RAID applications. You can
see the removable drive handles on the drives. These cases are usually very high quality,
and come with very beefy power supplies--and substantial price tags.
|
A very large, very nice server case, which
would make easier the life of someone
using it to implement a RAID array.
(Enlight's 8850.) |
Image © Enlight Corporation
Image used with permission. |
If you already have an existing system or for another reason don't want to go with a
specialty server case, another way to go is a separate RAID enclosure. This
is a fancy word for what is in essence an auxiliary case. It functions exactly the same
way that a regular case would except that it is external to the main system box and is
connected to it using one or more interface cables. Enclosures are also very expensive.
(Incidentally, if the enclosure also includes a RAID controller, then it is no longer just
an enclosure, it's an external, stand-alone hardware RAID array; see here for more.)
Next: Cabling and Power Requirements
