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OWC ThunderBay 8: Examples of Various Configurations using SoftRAID
Related: backup, Carbon Copy Cloner, cloning, hard drive, Other World Computing, OWC Thunderbay, OWC ThunderBay 8, RAID, RAID-0, RAID-1, RAID-4, RAID-5, SoftRAID, storage, Thunderbolt
Configurations up to 128TB (8 X 16TB). Larger capacities might become available later in 2020. Various drive choices available including standard and enterprise drives. Includes SoftRAID Lite or SoftRAID XT, which can also be used in non-RAID configuration.
This page shows off the outstanding versatility afforded with eight hard drives on the OWC ThunderBay 8 using SoftRAID.
Screen shots shown on ths page used the 48TB OWC ThunderBay 8 with eight Toshiba MD04ACA 6TB hard drives. Many other configurations of the OWC ThunderBay 8 are available, with drives up to 16TB each and enterprise and non-enterprise drives, but this changes only the relative capacity shown in these screen shots.
Single RAID-5 or RAID-4 volume, 8 drives
RAID-5 and RAID-4 are fault tolerant, able to degrade to a RAID-0 stripe should one drive fail. Failure of two drives means the volume is kaput.
RAID-5 and RAID-4 both use parity equivalent to the capacity of one drive, leaving usable capacity of 7 drives X 6TB = 42TB in this case.
RAID-4 (toggle to view) is the same as RAID-5, except that a specific drive is designated as the parity drive, versus distributed parity for RAID-5.
Single RAID-0 Stripe, 8 drives
RAID-0 delivers maximum performance and capacity, but failure of a drive means total loss of the volume, With 8 drives, RAID-0 is unwise unless rigorous backup procedures are in place.
8 drives X 6TB = 48TB volume capacity when all 8 drives are used for a single volume.
8 Volumes on 8 drives
Here, each drive is used for a separate volume. One might for example, used four of them as primaries, and 4 of them as respective clone backups. Or just use 8 volumes for whatever purpose.
Dual RAID-0 Stripes, 4 drives each
This approach is functionally similar to a RAID-1+0 (striped pair of mirrors) except that the user chooses when to backup, thus offering some additional leeway against system and user errors. With a RAID-10, there is one and only one copy and any such user or system or application errors are propagated to both mirrors, and a separate backup is required over and above the RAID. My preference for myself is as shown here.
Four RAID-1 Mirrors, 2 drives each
With eight drives, one can make four (4) fault-tolerant RAID-1 mirror volumes (2 drives each). Not my first choice, but it has its uses, such as four fault tolerant primary volumes for, say, different projects or clients.
Guaranteed-fast RAID-5 volume
Since hard drives slow down on the inner tracks, making an 8-drive 32TB fault-tolerant RAID-5 volume (first) on a 48TB total capacity leaves out the slowest parts of all the drives. This guarantees a certain minimum performance well above the slowest parts of the drives.
Here, Spare is a volume that uses the leftover space; Spare need not be created at all, but it is shown for completeness and it is also a RAID-0 stripe which speeds it up a bit versus a RAID-5. It might be used, for example, as a dumping ground for temporary work.
Dual 3-Drive RAID-0 Stripes, plus TimeMachine mirror
Here, dual 3-drive RAID-0 stripes are shown. One might for example use one as a clone backup of the other.
Dual 4-Drive RAID-5 volumes
Here, dual RAID-5 volumes were created, each with four drives.
One might for example want a fault tolerant volume for still photography and another separate fault-tolerant volume for videography.
RAID-1+0 — Striped Pair of Mirrors
All eight drives are used to stripe mirrored pairs of drives. Usable capacity is half of a simple RAID-0 stripe and performane is half as fast. The advantage is that one drive in each pair can fail and the volume remains intact. However, if two drives of one mirrored pair both fail, the volume is kaput.
Using RAID-1+0 is advised only for situations where a high level of fault tolerance is required along with still-strong performance.
With 8 drives, RAID-6 (dual parity drives) is highly appropriate and would be a better option, since any two drives could fail without taking the volume down, but SoftRAID does not support RAID-6—we can hope it will in the future.
Personally I would favor an 8-drive RAID-5 along with dual backups. While that increases the expense, backups are needed anyway, since RAID of any kind is NOT A BACKUP.