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The Basics of Using a RAID Calculator

RAID calculators will tell you the capacity left on each disk.


The Basics

The acronym RAID signifies a Redundant Array of Independent Disks. It is a virtualization technology for data storage that integrates the physical parts of disk drives into logical units. It can be used for data redundancy, performance management, or both. In one of these configurations, data is distributed among drives at certain performance levels called RAID levels. Each level represents the ability to perform certain tasks to a certain extent. Each balances the characteristics of availability, performance, reliability, and capacity in different ways and to different degrees.

Three techniques are used to achieve these desired results: mirroring, striping and parity.

  • Mirroring–data is copied identically to multiple drives.
  • Striping–partitions a drive’s storage space, creating a set of units with differing levels of system storage capacity. They range from a sector to several MB.
  • Parity–stripes data across more than one drive, allowing the array to continue operating even if one of the drives fails.

Levels of Storage

As mentioned, these arrays can store data at different performance levels. Here’s a break down of each RAID level:

  • Level 0– At this level, only striping is employed, not parity or mirroring. Data recovery is not possible at level 0. Here, the performance of reads and writes approaches every drive in the set’s sum of throughputs.
  • Level 1– Here only mirroring is used. Identical data is written to two drives, so any of the drives can be serviced by any read request. Redundancy is thus achieved. The sum of throughputs of the individual drives accounts for the hypothetical read speed of this configuration. Write speed, however, is dampened as the array’s speed is constrained by the slowest drive.
  • Level 1E– Striping and mirroring are both used here, as one of the remaining disks in the array is used to mirror every written stripe. 1E outperforms level 1 in terms of random read performance, though it is more common for level 10 to be used these days.
  • Level 4– Block-level striping is used at this level along with parity to achieve I/O parallelism. A single I/O read doesn’t have to spread over all the drives, improving small transfer performance.
  • Level 5– Despite being a higher level than Level 4, Level 5 is actually more susceptible to systems failures. Like level 4, this level has block-level striping with parity, but the parity here is distributed to the drives. All but one must operate, creating a greater failure risk.

There are other levels beyond these. For instance, Level 10 offers mirroring without parity, while at Level 50 there is distributed parity with block-level striping. Hopefully, though, you have a clearer idea of what a Redundant Array of Independent Disks is and how the different levels operate.

How Does this Technology Use a Calculator?

This brings us to the promised RAID calculator. To calculate the capacities of any one of these myriad configurations, you would need to know the characteristics of each level, like parity or mirroring. You also need to know the number of disks along with their size and multiply these dimensions together.

There are calculators available online which make this whole process much faster and easier. You can try using ours for free through our website here.

Not only can a RAID calculator figure out the capacity of a given configuration, it can help you evaluate how much usable disk space your array has left. That’s important because the mirroring and parity functions, for all their merits, take up a lot of disk space– sometimes as much as half. The calculator can help you plan accordingly.

Please be aware that using one of these calculators is not a substitute for backing up critical files. It is still vulnerable to hackers, controller failure, errors, and file corruption. Do your due diligence! Secure Data Recovery can recover data on all RAID arrays, and many other media devices such as HDD, SSD, and mobile phones. Dial us at 1-800-388-1266 for 24-hour customer service.

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