SoftRAID RAID 1+0 (RAID 10) FAQ

What is RAID 1+0?

RAID 1+0 (also called RAID 10) is a combination of striping (RAID 0) and mirroring (RAID 1).

Data is first mirrored in pairs of drives, then those mirrored pairs are striped together for performance.

This provides:

• High performance — due to striping
• Redundancy — due to mirroring

RAID 1+0 requires:

• A minimum of 4 drives
• An even number of drives

Is there a difference between RAID 1+0 and RAID 0+1?

Yes. RAID 1+0 is more robust than RAID 0+1.

RAID 1+0 (RAID 10)

• Data is mirrored first, then striped
• Built as multiple mirror pairs, then striped
• Failure behavior — can tolerate multiple drive failures as long as no mirror pair loses both drives
• More resilient and preferred configuration

RAID 0+1

• Data is striped first, then mirrored
• Built as two striped sets that are mirrored
• Failure behavior — a single drive failure effectively takes out one entire stripe set. After that, the array behaves like a single RAID 0 (no redundancy)

SoftRAID note: SoftRAID implements RAID 1+0 only. RAID 0+1 is not supported.

What are the ways to create a RAID 1+0 volume?

A RAID 1+0 requires a minimum of 4 drives, added in pairs. You can create it in two ways:

• Create the volume from scratch
• Convert from a RAID 0 — by adding drives and using the Convert function

Note: SoftRAID does not support converting AppleRAID 1+0 to SoftRAID.

Can a RAID 1+0 be converted to a RAID 0?

Yes. Use the Convert function to convert to RAID 0.

Note:

• The resulting RAID 0 will be a 2-drive RAID 0
• SoftRAID cannot convert a 4-drive RAID 1+0 into a 4-drive RAID 0

Can a RAID 1+0 be converted to a RAID 1?

No. SoftRAID does not support converting a RAID 1+0 to a RAID 1.

Workaround:

• Convert the RAID 1+0 volume to RAID 0
• Create a RAID 1 using the two drives removed during conversion
• Copy data from the RAID 0 to the RAID 1
• Repurpose the remaining drives

Can a RAID 1 be converted to a RAID 1+0?

No. SoftRAID does not support converting a RAID 1 directly to RAID 1+0.

Workaround:

• Create a RAID 0 using two additional initialized drives
• Copy data to the new RAID 0
• Delete the original RAID 1
• Use the Convert function to convert the RAID 0 to RAID 1+0
• The volume will automatically begin rebuilding

Can a RAID 5 be converted to RAID 1+0?

No. SoftRAID does not support this conversion.

Can a RAID 4 be converted to RAID 1+0?

No, not directly.

Supported workflow (example: 4-drive RAID 4):

• Convert the RAID 4 to RAID 0 — removes one disk
• Add additional drives and initialize them with SoftRAID
• Use Convert and select RAID 1+0
• Select the available drives and convert
• The volume will automatically begin rebuilding

Important: You cannot convert a 4-drive RAID 4 directly into a 4-drive RAID 1+0.

Can you shrink a RAID 1+0 to a smaller capacity?

Yes. Any SoftRAID volume can be shrunk to a smaller capacity. However, to use the freed partition space on the disks:

• New volumes must fit entirely within that contiguous space
• The available space must be contiguous to incorporate it with other free partition space

Examples:

• Single volume — if there is only one volume on the disks and it is shrunk, all freed space will be available for a new volume
• Multiple volumes — shrinking them does not guarantee usable space unless the freed space forms a single contiguous region

SoftRAID requires contiguous partition space to create maximum sized volumes with free partition space.

Can a RAID 1+0 be expanded?

Yes. Any SoftRAID volume can be expanded if there is contiguous free partition space immediately after the volume. In other words, the volume can grow to fill available space that directly follows it on the disk set.

If the available space is not contiguous, or does not come immediately after the volume, the volume cannot be expanded.

Can you increase the capacity of a RAID 1+0 by adding drives?

No. SoftRAID does not support expanding RAID 1+0 by adding drives.

To increase capacity:

• Create a new volume and migrate data

Are different RAID 1+0 configurations supported with 6 or more drives?

SoftRAID uses a single RAID 1+0 layout.

• Any even number of drives (up to 16) can be used
• You can control mirror pair assignments by selecting which disks are paired together during creation
• This provides some flexibility, but alternate RAID layouts are not exposed as separate configuration options

What happens when a single drive fails in a RAID 1+0?

• The volume remains mounted in a degraded state
• All remaining drives continue to be used
• When the failed drive is replaced, only that mirror member is rebuilt, not the entire volume

What happens when two or more drives fail in a RAID 1+0?

This depends on which drives fail:

• Same mirror pair — if both drives in the same mirror pair fail, the volume will not mount
• Different mirror pairs — if failed drives are from different mirror pairs, the volume will remain mounted and all data is accessible

This applies to any number of failures, as long as no mirror pair loses both members.

Example — 8-drive RAID 1+0:

• If one enclosure (containing one side of all mirror pairs) is lost, the volume can still mount in degraded mode
• When the enclosure is restored, the volume will automatically rebuild

Key Notes

• RAID 1+0 requires an even number of drives
• Conversions are limited — not all RAID levels are supported
• Resizing depends on contiguous partition space
• Capacity expansion requires creating a new volume
• Mirror pair selection can be controlled during setup