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"Can you elaborate on the 2nd and 3rd bullet, as I am unclear what the flexibility is, especially if the "layouts are not exposed as separate configuration options".
As an example, is it possible to have a RAID 1+0 with 2 stripes of 3 drives mirrored? If it does, this has the potential to behave like a multi-drive RAID 1 and theoretically allow the removal of at least one mirrored stripe set for offsite storage. Does SoftRAID allow any of this?"
When you created the RAID v 1+0 volume, you get to choose which disks are secondary disks, so you can set it up so that if you have two enclosures, one can contain the primary drives, the other the secondary drives.
No we do not support your idea of 6 drives with 2 sets of mirrors. There is no demand for that.
Posted : 12/04/2026 10:59 am
"Here too it is assumed that the R1 only has two drives. I suggest removing the reference to only two drives. "
Its what 90% of RAID 1+0 users have configured, and I would expect those with larger sets will easily understand they need to add 4 drives. This FAQ is already too long, and its not productive to carry every possible corner case.
"The net it is that if the RAID 5 data is ≤ X * n * (n-1) / (2*n -1), where X = the size of the drive, and n is the number of drives in the RAID 5, there is a work around. (As an example, if an R5 has n = 3 drives, and X = 6TB per drive (so the original R5 = 12 TB), then if the data in the R5 is ≤ 6 * 3 * ( 3 - 1) / ( 2 * 3 - 1) = 7.2TB, the work around I show in that thread can work.
You may want to add this to your FAQ."
FAQ's answer most "frequent" questions. These are such corner cases, they do not belong in documentation. It defeats the purpose of "frequently". ;-)
"If I understand the functionality of SoftRAID correctly, I believe there is a way to minimize downtime. If you swap out one drive at a time wit a large drive and allow each one to rebuild before swapping out the next one, at the end, you would only need to unmount the RAID just long enough to expand the RAID to fill the new drives."
This is covered in a resize/expand volume FAQ, and yes, is supported.
Users figure out how to resize Mirrors, RAID 4, RAID 5 by adding larger drives, so we can assume RAID 1+0 also.
Posted : 12/04/2026 11:14 am
smayer97 reacted
Topic starter
...
"If I understand the functionality of SoftRAID correctly, I believe there is a way to minimize downtime. If you swap out one drive at a time wit a large drive and allow each one to rebuild before swapping out the next one, at the end, you would only need to unmount the RAID just long enough to expand the RAID to fill the new drives."
This is covered in a resize/expand volume FAQ, and yes, is supported.
Users figure out how to resize Mirrors, RAID 4, RAID 5 by adding larger drives, so we can assume RAID 1+0 also.
I think this is the FAQ you are referring to? https://software.owc.com/knowledge-base/how-can-i-resize-a-softraid-volume/
P.S. I am not an expert, though I have been a long time user of RAIDs, so not seriously considered this approach before. I suspect there are many others that may not have considered this approach, and especially the less initiated.
This post was modified 6 days ago by smayer97
Posted : 14/04/2026 4:10 am
Topic starter
"Can you elaborate on the 2nd and 3rd bullet, as I am unclear what the flexibility is, especially if the "layouts are not exposed as separate configuration options".
As an example, is it possible to have a RAID 1+0 with 2 stripes of 3 drives mirrored? If it does, this has the potential to behave like a multi-drive RAID 1 and theoretically allow the removal of at least one mirrored stripe set for offsite storage. Does SoftRAID allow any of this?"
When you created the RAID v 1+0 volume, you get to choose which disks are secondary disks, so you can set it up so that if you have two enclosures, one can contain the primary drives, the other the secondary drives.
No we do not support your idea of 6 drives with 2 sets of mirrors. There is no demand for that.
So, does this mean that SoftRAID only supports 1 mirror in a RAID 1+0? So in a 6 to 18 drive config, there are only 2 stripes made up of half the drives each? If so, this would mean that no matter the number of drives, this implementation can only sustain a 2nd or more drive failure, as long as it is not in the same mirrored pair?
I am still trying to understand what "* This provides some flexibility, but alternate RAID layouts are not exposed as separate configuration options" means? Does SoftRAID instead apply some hidden logic to balance the number of stripes vs mirrors?
Also, is it possible to add drives to a RAID 1+0 (I understand that SoftRAID has not implemented the ability to increase capacity this way)? If so, what is the net effect?
Posted : 14/04/2026 4:23 am
Topic starter
*6 to 16 drive config
Posted : 14/04/2026 4:33 am
Topic starter
Can a RAID 1+0 be converted to to a RAID 1?
No. SoftRAID cannot do this. But you can do this in multiple steps:
1. remove the extra "mirrored" drives using the Remove function. This will leave you with a RAID 0 configuration.
2. create a RAID 1 using the removed drives. Note the capacity may be different that the original volume, depending on how many drives you remove.
3. Copy the data from the from the RAID 0 to the RAID 1.
The FAQ says "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"
Does this mean that the Remove function cannot be used for this purpose?
So, does this mean the Remove function cannot be used for the same purpose on a RAID 1+0? Does the same apply to a RAID 4 to remove the parity drive?
Posted : 14/04/2026 6:45 am
RAID 10 cannot withstand the "wrong two" drives failing at once. If your secondary disks are all in a second enclosure,then as many as half the drives can go missing and it will still mount. You just need one disk from each "mirror" pair, for the volume to be mountable.
Posted : 14/04/2026 11:36 am
@smayer97
"So, does this mean the Remove function cannot be used for the same purpose on a RAID 1+0? Does the same apply to a RAID 4 to remove the parity drive?"
the remove disk functions the same on any SoftRAID volume with parity. (You cannot "remove disk" on a RAID 0)
You can remove a disk, then add a new one. On RAID 10, or RAID 1, you can remove multiple disks at once depending on circumstances. And "add" two or more disks.
Example, you have an 8 drive RAID 1+0. And all the secondary disks are in enclosure two. (you can "set primary disks" any time to make this the case, if the volume is in sync)
you can use "remove disk" to remove all the secondary disks, then "add" 4 new disks at once and all will rebuild in the background.
A RAID 10 set up like this can also be disconnected and moved off line and the remaining disks will mount (essentially as RAID 0) then it will rebuild when reattached.
Posted : 14/04/2026 11:40 am
Topic starter
@smayer97
"So, does this mean the Remove function cannot be used for the same purpose on a RAID 1+0? Does the same apply to a RAID 4 to remove the parity drive?"the remove disk functions the same on any SoftRAID volume with parity. (You cannot "remove disk" on a RAID 0)
You can remove a disk, then add a new one. On RAID 10, or RAID 1, you can remove multiple disks at once depending on circumstances. And "add" two or more disks.
Example, you have an 8 drive RAID 1+0. And all the secondary disks are in enclosure two. (you can "set primary disks" any time to make this the case, if the volume is in sync)
you can use "remove disk" to remove all the secondary disks, then "add" 4 new disks at once and all will rebuild in the background.
A RAID 10 set up like this can also be disconnected and moved off line and the remaining disks will mount (essentially as RAID 0) then it will rebuild when reattached.
Maybe I was not clear as to what I was after regarding the Remove function. In the FAQ to Convert a RAID 1+0 to a RAID 1, the first step in the work around states to first "Convert ... to a RAID 0". Likewise, in the FAQ to Convert a RAID 4 to a RAID 1+0, the first step in the work around states to first "Convert ... to a RAID 0". My question is can the Remove function be used (instead of the Convert function) to remove the mirrored drives in RAID 1+0, or the parity drive in the RAID 4, to create a RAID 0, then you can go to the next step to be able to then convert the RAID 0 to a RAID 1+0 (re: original RAID 4)? Are they equivalent? Do they produce the same result?
In other words, are you left with the same thing if you use the Remove function on a RAID 1+0 as if you use the Convert to RAID 0? And likewise, are you left with the same thing if you use the Remove function on a RAID 4 to remove the parity drive, as if you use the Convert to RAID 0?
Also, though you stated in an earlier reply that SoftRAID does does not support a 3rd mirror for RAID 1+0, in your 8-drive config, is it possible to remove the 4 mirrored drives, add 4 new ones, let them rebuild, then rotate the 4 drives like this repeatedly (remove then add), so that one set of 4 drives can be taken off-site?
Posted : 16/04/2026 10:26 pm
If you want to "remove disk" in a RAID 1+0, you can, but it has more chances to go wrong.(Picking the "wrong" drives). In RAID 4, its easy to identify the parity drive, so you can remove the parity manually. But not sure why you would want to, rather than let SoftRAID automatically do it for you.
To your 8 drive RAID 1+0 question, its doable if you understand the limitations.
With a Mirror, you can pull out a drive, and bring it back later and the rebuild is automatic, for up to 15 secondary disks.
RAID 1+0 does not work like that. You can remove 4 disks, then use "remove missing disks", and "add disks" (4 more) and rebuild. and the 4 drives you removed will be a mountable volume. But they cannot be brought back and be expected to do anything automatically. You would need to delete the volume, then "add disks" and let it do a full rebuild. (and same for the 4 rotated drives, they will be an independent volume)
Posted : 18/04/2026 10:37 am
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