Is Parity a bottleneck/where to connect it?

[jmshrtn]

Hi folks.

 

I have a machine running unRAID 6.12.6 with a 9 device array with a single parity. The machine isn't terribly fast (i7-3770, 32GB of DDR3 and only PCIe 3.0 slots) but has enough IO to do the job for me. The motherboard (Intel Q77 based) has three SATA3 6Gbps connectors, and 2 SATA 3 3Gbps connectors, and I am using an LSI SAS2008 HBA to connect 8 drives (including the parity) and one of the on-board 6Gbps ports to connect the ninth. I'm wondering if I should leave the parity drive connected to the HBA (on the assumption that it performs better than the on-board controllers) or connect it to the on-board controller (on the assumption that there is not enough bandwidth in and out of the HBA).

Does anyone have any reckons?

[foo_fighter]

I have a similar setup. I don't think it matters but I'd also like to know if anyone's tried to optimize their setup. 300MB/s for Sata gen2 is more than the sustained read/write of your spinning disks. 

[JorgeB]

5 hours ago, jmshrtn said:

I'm wondering if I should leave the parity drive connected to the HBA (on the assumption that it performs better than the on-board controllers) or connect it to the on-board controller (on the assumption that there is not enough bandwidth in and out of the HBA).

It will be the same.