How many drives is too many?

[Fritz the Cat]

I have a Supermicro chassis that hold 24 2.5" drives. It's populated with 24 900GB drives. Is Drivepool suitable for a 24 drive pool? From what I've read, neither hardware RAID nor zfs is.

TIA

 

[Shane]

Yes. I know at one point Chris mentions their pool had 26 drives in it, that was a while back. Glancing through the same thread another user's pool is 35 drives for example. I'm pretty sure I've seen screenshots of pools with ridiculous numbers of drives (40+) elsewhere in the forums but I can't remember where or exact numbers offhand.

Theoretically DP can handle as many drives as Windows can support; the real limit is having good hardware.

P.S. The trick with hardware RAID, zfs et al is you don't make one giant array, you make an array of smaller (three to six disks each) arrays. The pro is you can get things like parity protection, bitrot healing, stuff like that. The con is the extra micromanagement and how fiddly adding and removing disks can get. If you have a machine with good hardware RAID management you can have DrivePool do the pooling for all the small arrays so you can get the best of both worlds, but it's still something I'd only recommend planning out carefully.

 

[Fritz the Cat]

Thank you sir. I will proceed as planned. I'd much rather have one big drive than many small ones.

And I know from past experience that Drivepool handles failed drives far far better than anything else out there.

[Christopher (Drashna)]

 I have one of the supermicro chassis that supports 36 bays (with 2x SAS2 expander boards), and have populated almost all of them. (there are a couple of slots that are dead, RIP, but 34 is still great).  And I use an LSI 9211-8i card (well a ibm serveraid card).  I've never had an issue with this setup, and it's been very snappy.   (well, some weird issues with firmware and driver versions for the LSI card, and some catastrophes with ReFS, just don't use ReFS)

 

Additionally, i've had a number of customers with even more than that (and at least one person with 100 drives and a PB of data, IIRC).  

And StableBit DrivePool doesn't care about the number of drives.  And it's designed to be very light weight, so that it works well on low end hardware, and higher end hardware.  

 

ZFS has issues with a large number of disks because of the scaled need of memory. The more disks (the more capacity), the more memory it needs. And ZFS really should be ran ONLY with ECC memory (you can run it without, but ... you shouldn't). 

Hardware raid has the issue that the larger the array is, the more likely you'll have a disk failure. And too many failures means that you lose the entire array.   And large enough, you heading into the territory where a distributed file system (eg, over the network) may be a better option. 

 

We do have a number of users that use snapRAID with the pool, though this isn't supported by us (there are a number of areas that don't play well, like having to completely rebuild after recovery).