Question HDD bottlenecking Plex server

[Fuergrissa0]

It's time to move on from my windows based PC converted to Plex media server and I would like advice on fixing the largest problem with the current setup. The problem is that if content is added to the software raid5 array the writing seems to saturate the array and playback suffers. It's about the only time the speed of the array (~130MBps ish) becomes a problem. Assuming that the writing ops are going to remain random is there an easy solution? Like network QoS for HDDs?

The build I am leaning toward will be a 1L PC with a thunderbolt or 10Gb Ethernet connection to a JBOD enclosure. My current thought is to have new media added to an NVMe drive and some type of scheduled service that will move everything to the array weekly or monthly for longer term storage. Are there better options? I'll probably move away from windows for the next build but don't know if that really opens anything up.

Thanks

 

[USAFRet]

This cries out for a dedicated NAS box.

4 bay Synology or QNAP.

1 drive for the system and new incoming files.
The other 3 for media storage.

A nightly scheduled task to push new stuff from the new pile into the mass storage area.

No need for NVMe or 10GBe on this.

 

[Fuergrissa0]

But if I want to watch something within 24hrs of it being added (very common) there is a risk of the same thing. Technically this would be the same on an NVMe drive but the span of time for the writes would be shorter. I don't usually get single files above 10gb but could be as high as 30GB. With the current setup that interrupts playback for several minutes.

Is there no way to prioritize reads? Or put a cap on the write speed for a single transfer?

 

[USAFRet]

But if I want to watch something within 24hrs of it being added (very common) there is a risk of the same thing. Technically this would be the same on an NVMe drive but the span of time for the writes would be shorter. I don't usually get single files above 10gb but could be as high as 30GB. With the current setup that interrupts playback for several minutes.

Is there no way to prioritize reads? Or put a cap on the write speed for a single transfer?

I don't know what your hardware currently is, but on my QNAP TS-453a...
2 movies out to 2 different systems
Music to a 3rd system
Backing up about 100GB to its second level storage
Reading in 200-300GB in Macrium Reflect backups from 2 different Windows systems

Simultaneously, with nary a burp in the video or audio, via a standard gigabit LAN.

 

[kanewolf]

I think the question is how was the RAID5 array created (what controller and how many drives) ?

 

[Fuergrissa0]

I think the question is how was the RAID5 array created (what controller and how many drives) ?

Intel controller on motherboard, 4 WD red 3TB sata drives. The utilization in taskmanager goes to 100% for several minutes when a new file is being unpacked (unRAR) or copied over from another drive for several minutes. During these times when the array is at 100% utilization is when the playback gets bad on any connected clients.

 

[USAFRet]

Intel controller on motherboard, 4 WD red 3TB sata drives. The utilization in taskmanager goes to 100% for several minutes when a new file is being unpacked (unRAR) or copied over from another drive for several minutes. During these times when the array is at 100% utilization is when the playback gets bad on any connected clients.

Playback suffering during unpacking is almost certainly a CPU/RAM issue, not a drive or RAID issue.

 

[Fuergrissa0]

Playback suffering during unpacking is almost certainly a CPU/RAM issue, not a drive or RAID issue.

The CPU and RAM have pretty low utilization during these times while the hard drive is pegged out... Also, when there is no such large transfer taking place I have never noticed any playback issues even while simultaneously transcoding multiple streams. I'm pretty convinced that the array IO is the problem... It's pretty easy to recreate the issue.

The read/write speed is not great, but it's enough, streaming a few clients with a mix of 4k and 1080p video is never a problem, it's just brief periods of saturation. it sounds like this is abnormal and most drives/arrays balance the IO better than this?

 

[kanewolf]

Intel controller on motherboard, 4 WD red 3TB sata drives. The utilization in taskmanager goes to 100% for several minutes when a new file is being unpacked (unRAR) or copied over from another drive for several minutes. During these times when the array is at 100% utilization is when the playback gets bad on any connected clients.

Motherboard disk controllers are not known for high performance with RAID.
What motherboard model ? (Q77 or Z690) ?
I would think your best bet would be a dedicated RAID card that will handle the RAID5 in hardware.
I don't think the motherboard RAID hardware can do the RAID5 parity calculations in hardware. That makes it quite slow. Get real RAID hardware if you want to use RAID5.