Hello,

 

I have one PCIe M.2 drive I would like to use to run my VM's on and store my music collection. I was wondering if unRAID would allow me to do the following:

 

1. Can I use a PCIe M.2 drive for storage?
2. Can I backup this drive with a regular HDD?

Edited January 20, 20188 yr by Twisted

Yes to both questions.

@johnnie.black Thank you for the response. Since unRAID only has one drive pool, can you point a VM or storage folder directly to the M.2 drive? I will only have one in my array, as most of my drives will be standard HDD.

Edited January 21, 20188 yr by Twisted

4 hours ago, Twisted said:

@johnnie.black Thank you for the response. Since unRAID only has one drive pool, can you point a VM or storage folder directly to the M.2 drive? I will only have one in my array, as most of my drives will be standard HDD.

It is not recommended to have a VM with its system drive running off a drive in the main array as the limited write performance of the parity protected array adversely affects performance of the VM.     Normally VMs are either run from the cache pool, or from a drive mounted outside the array using the Unassigned Devices (UD) plugin.  Having said that you can specify exactly what drive(s) a VM should use.

@itimpi Thank you for the information. My main goal is to put my music collection on my M.2 drive. I was also planning on running Plex via Docker or an app (whichever is more efficient) on the drive. Do you have any suggestions on how to setup my M.2 drive? just point everything to it or setup via the Unassigned Devices (UD) plug?

Edited January 21, 20188 yr by Twisted

29 minutes ago, Twisted said:

@itimpi Thank you for the information. My main goal is to put my music collection on my M.2 drive. I was also planning on running Plex via Docker or an app (whichever is more efficient) on the drive. Do you have any suggestions on how to setup my M.2 drive? just point everything to it or setup via the Unassigned Devices (UD) plug?

I would have suggested a really cheap SSD for the music collection, since there isn't any transfer speed needs and you will have a minimum of writes so wear isn't an issue.

 

Reserve your high-end SSD for something that requires the performance.

33 minutes ago, pwm said:

I would have suggested a really cheap SSD for the music collection, since there isn't any transfer speed needs and you will have a minimum of writes so wear isn't an issue.

 

Reserve your high-end SSD for something that requires the performance.

Ditto - I don't think you'll need to run Plex off an M.2 - just use a normal SSD again.  For my setup, I just have my VMs on my M.2 as an unassigned drive and my docker appdata and cache 2 normal SSDs in a pool

I use a Crucial Mx500 500gb running as a cache disk and run my apps and vm's on it with out any issues.

Why not use it as a Cache disk? 

My SSD runs at about 520 MB/s Write speeds and my M.2 drive is Read/Write speeds up to 3,200 MB/s. It seems like certain applications would benefit more by utilizing an M.2 drive vs SSD. I initially thought about Plex, as it is trying to load massive libraries of images, meta data, etc. Has anyone tested the performance gains on applications using an M.2 vs SSD (Plex, Docker, VMs, etc)?

Note that your M.2 drive is a SSD. It's just a different form factor than 2.5" and using a different interface than SATA.

 

A normal SSD with 500 MB/s is many times faster than the real-time requirements for streaming HD-resolution (even 4k) video. And it's about 3000 times faster than he uncompressed sound from an audio CD. If your Plex needs to transcode multiple videos concurrently, then the main bottleneck will be the computations - not the storage.

@pwn I was more concerned about Plex pulling up my media images. It seems like I get a slight delay when browsing my collection with a standard HDD. I was hoping the M.2 drive would fix that issue. 

 

So it sounds like there is no noticeable performance enchantment going from 500 MB/s to over 3,000 MB/s for VM's, Docker or Plex?

A HDD can only handle about 100 I/O requests per second. If it spins at 7200 rpm, then that is 120 revolutions/second. Which means the HDD first have to move the heads to the correct cylinder and then wait for the correct sector to rotate in under the head.

 

A normal SSD can handle more than 50,000 IOPS.

Some M.2-based SSD can handle over 400,000 IOPS.

 

This means that moving from a HDD to a SSD will make a huge difference in how many file accesses Plex can do per second.

 

When it comes to transfer rates, the difference is less. A SATA-connected SSD only manages about 2-3 times the transfer rate of a HDD. But it's normally the seek speed that is important when you browse for information.

21 hours ago, Twisted said:

My SSD runs at about 520 MB/s Write speeds and my M.2 drive is Read/Write speeds up to 3,200 MB/s. It seems like certain applications would benefit more by utilizing an M.2 drive vs SSD. I initially thought about Plex, as it is trying to load massive libraries of images, meta data, etc. Has anyone tested the performance gains on applications using an M.2 vs SSD (Plex, Docker, VMs, etc)?

I did some initial testing with a older toshiba XG3 256GB (2400/1500MB) as cache drive, and didn't notice any gains on my server compaired to the MX500 (560/510MB). I'm running on a gigabit network and have 5 docker instances including plex (12tb lib, 4 users) and a single VM. (based on my iotop logging of workloads, and my "feeling" playing with plex, did not measure it) If your running 10GBe and more vm's it will probably be a different story. 

 

For me the turning point was 2 years more warranty and save 80euro's compaired to the samsung 960evo. 

What the exact turning point is hard to say, depends on your build.

@SiNtEnEl Thank you for sharing your experience. I appreciate the help and advice from everyone. I think since I already have my M.2 drive, I will use it for Plex, Docker and VMs.  I will use my SSD for cache.

On 1/21/2018 at 10:47 PM, Twisted said:

@pwn I was more concerned about Plex pulling up my media images. It seems like I get a slight delay when browsing my collection with a standard HDD. I was hoping the M.2 drive would fix that issue. 

 

So it sounds like there is no noticeable performance enchantment going from 500 MB/s to over 3,000 MB/s for VM's, Docker or Plex?

 

I can't speak to the performance of unRAID yet, as im still on the fence my self. But I moved my plex to my m.2 nvme and found a very noticeable increase. Browsing library, and poster art was nearly instantaneous. I would also recommend you setting the trans-code folder to the ssd (if your okay with the massive amounts of writes), otherwise a ram-disk. Very noticable increase, especially on directplay/steam devices like xbone, pc, roku, ect. 

@tbonedude420 Thank you for the feedback. I just setup Plex on my M.2 and it is looking promising. Once I correct the error I am getting, I will start testing the responsiveness of the interface. I am debating on the trans-coding folder next. I only have 32GB of RAM and may upgrade to 64GB, as it sounds like utilizing this method is better for the overall hardware of the server.