I’m trying to do some math on potential Unraid build, and where my bottlenecks my be.

Currently I run a DS1019, with 5 x 14TB WD Red Pros in RAID 6. Single gigabit connection to the network.

On this I can comfortably run, direct play, through Plex a 4K HDR BluRay REMUX (~100GB file), and even a few 1080p direct play streams (smaller ~15TB files) same time. All clients are AppleTV 4K’s.

Looking at Unraid, I’m aware this isn’t RAID, so is limited in ways by single drive performance.

 

Assuming all WD Red Pro drives, and ignoring improvement to write performance with an NVMe/SSD cache pool. What would be theoretical/approximate real world read/write rate be?

 

So far I got:

4K BluRay has a bitrate of up to 144 Mb/s

WD Red Pro’s are SATA 6Gb/s. So 6000Mb/s? (product page says say up to 255MB/s?)

My internet is 250/100 (I’m using this to gauge download speeds from SAB to the storage).

Ethernet server to ATV is 1Gb/s.

 

I’m trying to gauge if I can say be downloading something to the array at my max internet speed, whilst reading a 4K remux from the exact same drive in the array (obviously download would go to cache, but trying to gauge worst case)?

 

I’d be great if there was a calculator, where you could punch in some rough specs, and it estimates where you potential bottleneck is, and max read/write (obviously based on theoretical max’s, but still would be great to show “hey, look at your drives” or “look at your nic”).

52 minutes ago, te5s3rakt said:

WD Red Pro’s are SATA 6Gb/s. So 6000Mb/s? (product page says say up to 255MB/s?)

6Gb/s is the interface, normal reads will never get close that that, it should be around 250MB/s max in the outer tracks, slowing down as it starts using the inner tracks, max speed at the most inner tracks should be around 100MB/s.

1 hour ago, JorgeB said:

6Gb/s is the interface, normal reads will never get close that that, it should be around 250MB/s max in the outer tracks, slowing down as it starts using the inner tracks, max speed at the most inner tracks should be around 100MB/s.

So I could be considering 100MB/s as my average? Anything above is bonus of circumstance. Which next bottleneck in throughput I guess is the gigabit Ethernet that’d top out at 125MB/s?

 

Looking at that remux as an example, on the inner track, I can be able to theoretically direct play 5 play movies tops (all remux’s)?

Of course this assumes inner track, all 5 movies on the same drive, all about 100GB each (they seem to vary from 60-100 depending on release year). Likely I’d be able to achieve higher, because the likelihood of only hitting movies on the same drive, in a 6 drive storage volume, would be pretty low.

1 minute ago, te5s3rakt said:

So I could be considering 100MB/s as my average?

That's the low end for a single stream, multiple streams from the same disk can get slower due to random access, you'd need to test to see how many streams it can handle.

 

6 minutes ago, te5s3rakt said:

is the gigabit Ethernet that’d top out at 125MB/s?

Yes, usually around 115MB/s usable.

16 minutes ago, JorgeB said:

That's the low end for a single stream, multiple streams from the same disk can get slower due to random access, you'd need to test to see how many streams it can handle.

 

Yes, usually around 115MB/s usable.

Cool. Sound’s like, even mostly assuming worst cases, unraid will still meets my requirements. I’d need a perfect storm of negative circumstances at the same time to start getting stuttering in the volume of streams I’d concurrently have running (likely 4 tops, because 4 TVs, 2 of which at 1080p anyway, but planning to upgrade them to 4K at some point).

 

Thanks. That sets my mind at ease.