Is there a way of creating multiple arrays?

 

Here are my thoughts on why I would consider going there.

 

I recently came across a Reddit post about a sysadmin who had a dual drive failure on an array he built. Luckily, it wasn't in production at the time, but it reminded me of a thought I had about arrays and parity disks.

 

Currently, Unraid provides up to two parity drives. This should be sufficient for most people in most situations. But, as the number of data disks in the array increases, the probability of a multi-disk event also increases. A six-disk array with two parity drives will have a lower likelihood of a multi-disk event than a 24-disk array with two parity drives.

 

The ability to create multiple arrays with a smaller number of data drives and parity drives would keep this probability factor down while still providing the overall storage capacity. The shares could still be spread across all of the arrays.

 

Thoughts?

 

 

At the moment you can only have one array of the Unraid type although we are promised at some time multiple ones will be supported.    However you can have lots of pools using the more traditional RAID types supported by either btrfs or zfs.

I would also love the ability for multiple arrays. For me the want for NVME fast storage. I could have a small super fast array with parity, then a 2nd slower array with spinning disks.

If I add an NVME drive to a normal array it's only going o be as fast as the slow parity disk.

And I don't want to deal with RAID and cache pools, or cache pools and backup.

26 minutes ago, Maximus01701 said:

I would also love the ability for multiple arrays. For me the want for NVME fast storage. I could have a small super fast array with parity, then a 2nd slower array with spinning disks.

If I add an NVME drive to a normal array it's only going o be as fast as the slow parity disk.

And I don't want to deal with RAID and cache pools, or cache pools and backup.

I think what you're really looking for is not really multiple arrays, but a cache pool for the existing array. None of the arrays (other than a ZFS AFAIK) have any striping, so you wouldn't see any real performance benefits with an array of NVME drives. I think you might even see a performance degradation (compared to single mounted NVME) as the array functions require all disk activity when writing to a disk in order to calculate the parity bits. That is the reason Unraid arrays don't have spectacular throughput performance and the addition of cache pools to speed up writing and reading (in certain configs).

On 2/6/2025 at 3:05 AM, aglyons said:

Is there a way of creating multiple arrays?

 

Here are my thoughts on why I would consider going there.

 

I recently came across a Reddit post about a sysadmin who had a dual drive failure on an array he built. Luckily, it wasn't in production at the time, but it reminded me of a thought I had about arrays and parity disks.

 

Currently, Unraid provides up to two parity drives. This should be sufficient for most people in most situations. But, as the number of data disks in the array increases, the probability of a multi-disk event also increases. A six-disk array with two parity drives will have a lower likelihood of a multi-disk event than a 24-disk array with two parity drives.

 

The ability to create multiple arrays with a smaller number of data drives and parity drives would keep this probability factor down while still providing the overall storage capacity. The shares could still be spread across all of the arrays.

 

Thoughts?

 @space waves

 

Interesting idea — multiple smaller arrays could definitely help reduce risk and improve data isolation. Would love to see Unraid explore this as an option in the future!

Would love to see actual Storage related features added, namely support for Multiple Arrays with the unraid type. Many have been asking for this feature for years if not well over half a decade now.

I feel like there is often a misunderstanding that everyone wants improved performance for the second ARRAY group.

Modern NVMe is already fast enough to saturate a 10G NIC, so speed improvements aren't the primary reason (at least for me).

Just to be clear, the reason I want an second Unraid ARRAY for NVMe/SSD is the following:

(1) You improve the amount of space you can use, especially when you have mixed sized drives

(2) You'd be reducing usage on the non-parity volumes provided, particularly for writes

(3) You have a better recovery scenario since a single device can be mounted and readable

(4) You can easily grow by adding additional devices and not be constrained by the underlying RAID method you started with

(5) You can mix and match filesystems across the group, adding to flexibility

So, in short, you'd use a second array for all the same reasons you came to use Unraid in the first place.

I just wish this feature would show up, I think there are loads of compelling reasons to offer it and people will use it.

I also wish for such a feature to be added. because I want to have seperate drives for my VM's (all ssd) and for storage I have hdd's.

1 hour ago, Gabcraftia said:

I also wish for such a feature to be added. because I want to have seperate drives for my VM's (all ssd) and for storage I have hdd's.

You do not want SSDs in an Unraid type array as they can then not be trimmed. Why not simply put them into one or more pools as SSDs in pools CAN be trimmed.?

10 hours ago, itimpi said:

You do not want SSDs in an Unraid type array as they can then not be trimmed. Why not simply put them into one or more pools as SSDs in pools CAN be trimmed.?

But is it possible to get redundancy in a pool? I'm quite new to unRAID so I don't know a lot yet.

3 hours ago, Gabcraftia said:

But is it possible to get redundancy in a pool? I'm quite new to unRAID so I don't know a lot yet.

Yes. Both BTRFS and ZFS support various flavours of RAID for redundancy when used in pools.

I am also waiting for the multiple array feature for years. It would help me so much exchanging my 6TB with 14TB HDDs. Wasn't the feature promised for 2026?

Edited June 18Jun 18 by Raki72

46 minutes ago, Raki72 said:

I am also waiting for the multiple array feature for years. It would help me so much exchanging my 6TB with 14TB HDDs. Wasn't the feature promised for 2026?

Yes it was promised here: https://newsletter.unraid.net/p/unraid-2025-year-in-review

Will it actually happen? Who knows...