Best organization of drives

[Tartifless]

Hello team,

I have a ws2016 machine with a gigabyte mobo with 6 sata ports and 2 pcie adaptec 6805 cards (8 port) full of drives.

In total I have 19 drives in my machine.

It includes 3 pools: 2 of 2 drives and one of 5 drives, all have duplication enabled.

 

I was wondering what is the best in terms of performance ? Should drives from a same pool be placed on the same controller or on different controllers ?

What would the pros and cons be ?

[Christopher (Drashna)]

Honestly, it shouldn't matter too much.  The drives aren't going to saturate the bus, so this wont make a different. 

For instance, each PCI-e card, assuming it's PCI-e 2.0 8-lane, that can support ~20 hard drives being saturated.  And that you have 2, and even if the onboard sata ports were using just a single lane... 

You should have no problems here.  (I'm using 24 drives on a single LSI SAS controller, and have had zero issues)

[Umfriend]

I would just consider to split the 2x2 Pools so that each Pool has one drive on each adapter and perhaps split the 1x5 Pool into two and use Hierarchical Pools for duplication and have each underlying Pools' drives on seperate adapters. Why? Should one adapter fail then you can still access all files without having to connect all HDDs to the other adapter. Sure, you will do so anyway but at least you can now read before you do that.

[Tartifless]

3 hours ago, Umfriend said:

I would just consider to split the 2x2 Pools so that each Pool has one drive on each adapter and perhaps split the 1x5 Pool into two and use Hierarchical Pools for duplication and have each underlying Pools' drives on seperate adapters. Why? Should one adapter fail then you can still access all files without having to connect all HDDs to the other adapter. Sure, you will do so anyway but at least you can now read before you do that.

Thanks, i'll do that.

Just for information, where in the balancing options can i do that (hierarchical pools usage) : i am in french so not easy to find.

Anyway this will require a pool reorganization which might take some time as the 5 drive pool is made of 2x10TB + 3x8TB and is 80% full (a new 10TB drive is on order)

[Christopher (Drashna)]

@Tartifless Basically, go to add a new pool (the "+" at the top.  You can add pools to that pool.   So you could have a pool with the disk from one controller in a pool, the disks from the other controller in another pool, and then pool together those two pools.   If you're using duplication, enable it on the top level pool, and you have a copy on each controller, basically. 

This isn't required, but it's not a bad idea, in case a controller fails. 

[Umfriend]

Just note that with a 3x10TB + 3x8TB setup, hieracrichal Pools will suffer a deadweight loss. Why? Because you can not create two non-duplicated Pools of the same size. So when you then create a Hierarchical Pool for duplication, it will see one 28TB and one 26TB drive and 2TB will be unusable.

You don't happen to have a 2TB HDD lying around somewhere, do you?

Edit: Of, should you have, say, a 6TB HDD, you could do 3x10 and 3x8+1x6TB.