30 Drive Limit and Array vs Pools

[Jrac86]

I have a 48 bay netapp (2 daisy chained 24 bay units) and am considering unraid to manage the drives. I see there is a 30 drive limit for the array, but that you can now use multiple drive pools with thr latest version. I would make my main array use the first 30 drives. The remaining 18 drives would most likely be used for drive pools. What are the differences between the main array and the drive pools? Can I still have parity drives for the drive pools? My other option is to split the netapps and just manage 2 separate unraids, but would prefer to keep it all within one place. Thanks for any advice in advance.

[Vr2Io]

1 hour ago, Jrac86 said:

The remaining 18 drives would most likely be used for drive pools. What are the differences between the main array and the drive pools?

Pools are not file base, i.e. you can't read/write individual disk while array disk can.

 

1 hour ago, Jrac86 said:

Can I still have parity drives for the drive pools?

No.

[itimpi]

With the main array you have specific drives as parity drives and the Unraid specific version of parity handling operates.

 

With multi-drive pools the BTRFS format is used and this supports a variety of its implementation of RAID.   Instead of separate parity you get redundancy by more than one copy of any data being stored.    The pools tend to be higher performance for given drives than the main array.   You can have multiple pools and many people have pools optimised for different Use Cases.

 

there is a roadmap item for Unraid to support multiple ‘main’ arrays but I would expect this to be some way off.

[MrGrey]

Not an expert, but I'm pretty sure SpaceInvader has a ZFS pool in his main server. I don't know the specifics any more than anyone else who has watched his videos. I think it's a valid option, considering your resources.

 

Unraid is uber-flexible, but 2 parity drives divided by 48?... I think the 30 drive limit is just LimeTech being nice and hoping people have common sense.

 

I hope this helps.

 

MG.

[TheIronAngel]

I have a similar situation, I have had a pair of 24-bay enclosures fall into my hands recently and nabbed a cheap 16e HBA only to realise that I'd be wasting my time getting more drives since I can't use more than 30 of the 48 bays. I was rather disgruntled to find that 'Unlimited' was caveated with "actually only 30 drives with redundancy, but you can *connect* an unlimited number of drives, good luck using more than 30 though" - I've done some more reasearch and have decided that TrueNAS is what I'll likely need to move over to so I can use what I actually have.

 

Granted when I purchased Unraid I was happy with the 14 drives I already had and am only a little miffed about the cap/inability to utilize more than 30 drives. I would love an option that said "I'm dumber than a lead brick, let me use more than 30 drives at my own risk" since the data I'm storing is non-critical, easily replaced and I just want a massive pool to put it on.

 

In summary, I'll keep using Unraid until either:

Unraid implements ZFS pools/multiple partiy pools or removes/allows users to exeed 30 drive arrays.

or

I can afford to kit out a 24-bay full of 8TB drives then I'll migrate to TrueNAS and kiss Unraid bye-bye.

[itimpi]

1 hour ago, TheIronAngel said:

I have a similar situation, I have had a pair of 24-bay enclosures fall into my hands recently and nabbed a cheap 16e HBA only to realise that I'd be wasting my time getting more drives since I can't use more than 30 of the 48 bays. I was rather disgruntled to find that 'Unlimited' was caveated with "actually only 30 drives with redundancy, but you can *connect* an unlimited number of drives, good luck using more than 30 though" - I've done some more reasearch and have decided that TrueNAS is what I'll likely need to move over to so I can use what I actually have.

 

Granted when I purchased Unraid I was happy with the 14 drives I already had and am only a little miffed about the cap/inability to utilize more than 30 drives. I would love an option that said "I'm dumber than a lead brick, let me use more than 30 drives at my own risk" since the data I'm storing is non-critical, easily replaced and I just want a massive pool to put it on.

 

In summary, I'll keep using Unraid until either:

Unraid implements ZFS pools/multiple partiy pools or removes/allows users to exeed 30 drive arrays.

or

I can afford to kit out a 24-bay full of 8TB drives then I'll migrate to TrueNAS and kiss Unraid bye-bye.

It is 30 drives in the main array, but you can also have multiple pools of up to 30 drives.  I think this makes the max number of drives supported of the order of 1000.

 

There is a roadmap item to add multiple main arrays - no idea on the ETA or the number of such arrays that will be supported when/if this feature arrives.

[iamroot4ever]

On 6/26/2022 at 8:30 AM, Jrac86 said:

Can I still have parity drives for the drive pools?

 

On 6/26/2022 at 10:29 AM, Vr2Io said:

No.

 

Since this thread is still popping up at the top of Google searches for "unraid array size limit," I thought I would update the details based on my experiences using Unraid 6.12.4+ :

 

The direct answer of "no, you can't have parity drives in pools" is technically correct if you are referring to "parity drives" in the way the array uses them. However, You can - and should - configure pools with redundancy as allowed, or striping as preferred. I have a pool just for cache without redundancy that is btrfs striped for optimum performance, and an SSD pool configured as RAIDZ.1 ZFS for redundancy on my appdata / docker config setup. The addition of ZFS in particular has opened up a ton of options going forward, though the share confguration and mover config not allowing easy pool-to-pool data migration is the biggest hiccup. Of course this can be overridden by creative script work, so YMMV.

[Vetteman]

Addition of allowing multiple Arrays would be neat. What would be the next consideration? Print server? Request for a directory structure like Novell Netware' s NDS or Microsoft's ADS?

 

Of course a NDS or ADS object could also be created for the NAS  inr an existing directory structure, but I was thinking in an environment where the NAS is the primary or only file server? But I think that would be overkill.

 

PS: Just found out there is indeed a print server plugin in the APPS store - CUPS.

Edited January 1 by Vetteman

[tby]

This limitation of one 'array' of up to 28 storage + 2 parity drives has been the thing keeping me from buying into unraid. With my last additions I'm at 30 drives in two volumes on DrivePool, with maybe six months before I need to grow it again.

[trurl]

Do you really need this many drives? I always say every additional disk is an additional point of failure. Do you have a lot of small disks, or do you really need 100s of TB capacity?

[itimpi]

56 minutes ago, tby said:

This limitation of one 'array' of up to 28 storage + 2 parity drives has been the thing keeping me from buying into unraid. With my last additions I'm at 30 drives in two volumes on DrivePool, with maybe six months before I need to grow it again.

Many people are now creating ZFS or BTRFS 'arrays' (as Unraid pools) which allows you to go well above the 30 drive limit.  If I remember correctly you can have up to 60 drives in a pool and you can have multiple pools.

 

I think it is unlikely that the main Unraid array type will ever go above the 28+2 limit because that is a lot of drives to only be protected by 2 parity drives, but hopefully in the future you can more than one of those.

[tby]

Yes, I have hundreds of TBs of storage on drives no smaller than 10TB that I'd like to migrate from DrivePool to unraid. Particularly because an 'unraid array' is like a DrivePool with optional real-time parity. Also hopefully it would allow my drives to spin down when idle, which isn't happening with DrivePool so my storage is consuming ~3.8A at all times when it could be under 1A nearly all the time.

 

IMO most people who want ZFS missed that it was designed for Enterprises who upgrade capacity by replacing the whole thing or adding completely populated shelves. I think BTRFS is better suited for most use cases where throughput is a priority but it still comes with a warning not to use its RAID5/6 implementation for data you're not prepared to lose. I know some commercial NAS layer lvm/mdadm over BTRFS for RAID but I haven't seen that on anything I can run on my own hardware, and DIY-ing that is deeper into the weeds than I want to go. Plus, again, I'd like most of my disks to be spun down most of the time, which takes any sort of traditional striped RAID off the table.

 

So, yes, I really need more than 30 drives. Preferably not all in a single 'unraid array' but I'd take that if that was what was on offer.

[trurl]

2 minutes ago, tby said:

not all in a single 'unraid array'

I think that is planned for a future version but no timeline

[hawihoney]

15 hours ago, itimpi said:

Many people are now creating ZFS or BTRFS 'arrays' (as Unraid pools) which allows you to go well above the 30 drive limit.  If I remember correctly you can have up to 60 drives in a pool and you can have multiple pools.

 

Yes, but all these pools don't work like the Unraid Array - reading/writing only from/to those individual drives in use. IMHO this is one of the most important parts of Unraid. Other NAS support Docker, they support VMs, they support ZFS/BTRFS, but they can't support the Unraid Array. The reasons to use the Unraid Array back in 2005/2008 are still valid in 2024.

 

I hope we will see multiple Unraid arrays in the near future. Multiple Unraid Array pools would be a dream.