Moving disks within NAS between controllers

[mgrobins]

Hi,

 

I have a supermicro mb with xeon-D SOC and LSI 9211-8i HBA (IT mode).

All of my disks are 4TB SATA 3.5" disks.

 

I currently have 6 disks on the mb SATA ports and 1 on the HBA. Volume is arranged into one RAID6 Vol on BTRFS. Jun's loader and DSM 6.2.x

 

Adding more disks I am considering moving all to the HBA (total of 7 or 8 currently)

 

I have read a fair amount of conflicting data about performance/reliability use/don't use write cache etc.

 

I'd appreciate some consolidated feedback regarding:

 

1. will re-ordering or shifting disks cause a problem? (I'd move array then expand after it's set up).

 

2. I use 16GB of ECC RAM. Are there recognised, valid concerns about data corruption using write cache or is that just a furfe doing the rounds?

 

3. I've read a number of sources citing HBA LSI 9211-8i as faster overall than onboard SATA due to the onboard using CPU offload and general increases in latency. I'd say higher IOPS however not certain how that translates into real world latency or transfer rates for access.

 

4. I think all disks on one controller may be more reliable. Controller dies I can simply throw in a new one or move disks to hardware containing that controller?.

 

As additional info I have a 10GBe link to my main PC I use for video data being shifted to / from the NAS. I see about 650MB/s - 700MB/s currently with 6 disks in the NAS and my PC using a RAID0 array of 2 SATA III SSD's (Not NVMe). I *think* I am seeing a bottleneck on the NAS with approx. 120MB/s max for a mechanical drive?