Enter your disk size, number of disks, and RAID type into the calculator to determine your usable storage capacity.

ZFS RAID Calculation Formula

The following formula is used to calculate the usable storage from your disks in a Z FS RAID configuration.

Usable Storage = (Number of Disks - Redundancy Level) * Disk Size

Variables:

  • Usable Storage is the amount of storage available for data (GB)
  • Number of Disks is the total number of disks in the RAID array
  • Redundancy Level is the number of disks reserved for parity (RAIDZ1 = 1, RAIDZ2 = 2, RAIDZ3 = 3)
  • Disk Size is the capacity of each individual disk (GB)

To calculate the usable storage, subtract the redundancy level from the number of disks and multiply the result by the disk size.

What is ZFS RAID Calculation?

ZFS RAID calculation refers to the process of determining the usable storage capacity of a ZFS RAID array. This involves understanding the number of disks in the array, the type of RAID configuration, and the size of each disk. Proper calculation ensures accurate storage planning and data management.

How to Calculate Usable Storage?

The following steps outline how to calculate the usable storage using the given formula.

  1. First, determine the size of each disk and the total number of disks in the array.
  2. Next, determine the redundancy level based on the RAID type (RAIDZ1 = 1, RAIDZ2 = 2, RAIDZ3 = 3).
  3. Use the formula: Usable Storage = (Number of Disks – Redundancy Level) * Disk Size.
  4. Finally, calculate the usable storage by plugging in the values.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Disk Size = 500GB

Number of Disks = 6

RAID Type = RAIDZ2

FAQ

1. What is usable storage?

Usable storage is the amount of storage capacity available for data after accounting for redundancy and other overhead in a RAID array.

2. How is usable storage different from total storage?

Total storage is the combined capacity of all disks in the array, while usable storage is the actual capacity available for data after redundancy and parity are considered.

3. How often should I use the ZFS RAID calculator?

It’s helpful to use the ZFS RAID calculator whenever you add or remove disks, change RAID configurations, or need to plan your storage requirements accurately.

4. Can this calculator be used for different RAID types?

Yes, you can adjust the RAID type field to match the desired RAID configuration to calculate the usable storage accordingly.

5. Is the calculator accurate?

The calculator provides an estimate of your usable storage based on the inputs provided. For exact figures, it’s best to consult your storage documentation or a storage professional.