Newbie filesystem and ECC questions

[paokkerkir]

Hi guys, I'm in the planning phase of my first NAS, and oh my God, what a rabbit hole this is.

 

First of all, the hardware I'm going to use:

i7 4790k - z97 - 32gb ddr3 - quadro p400 - 2.5g ethernet

512gb nvme - 240gb ssd

2x16tb hdd's with plan to add on later

 

I decided on using Unraid for my OS for ease of use and having the option to add on disks later in my array.

 

First of all, I understand that ECC ram is vastly preffered - especially for ZFS. Should I not use the harware I plan at all and opt for an ECC based solution, even if I'm using XFS?

 

Planning on using XFS for the array - this is still what is recommended from what I understand.

 

Especially for the cache I have some questions. I'm planning on using the 512gb nvme as cache for appdata/docker etc (with backups daily) and the 240gb ssd for plex cache only. This is still possible with XFS? Is it not the recommended way?

 

Or would it be better to splash on 2x1tb nvme's and use them as ZFS cache with XFS array?

 

I get that with Btrfs there are some issues for cache, not sure if this is still the case.

 

Filesystems left me a bit confused.

 

Thanks in advance for any suggestions!

 

 

Edited February 26 by paokkerkir

[TimTheSettler]

3 hours ago, paokkerkir said:

First of all, I understand that ECC ram is vastly preffered - especially for ZFS. Should I not use the harware I plan at all and opt for an ECC based solution, even if I'm using XFS?

 

ECC is quite expensive and you already have the hardware.  It's also one of those one-in-a-million situations that isn't worth worrying about.  Will you be using a parity HDD?

 

3 hours ago, paokkerkir said:

Planning on using XFS for the array - this is still what is recommended from what I understand.

 

Use XFS.  Wait for ZFS to mature and then maybe use it later (you can switch over at a later time).  There are a whole list of benefits and disadvantages that it's better to keep it simple for now and use XFS.

 

3 hours ago, paokkerkir said:

Especially for the cache I have some questions. I'm planning on using the 512gb nvme as cache for appdata/docker etc (with backups daily) and the 240gb ssd for plex cache only. This is still possible with XFS? Is it not the recommended way?

 

It's a good idea to double up the NVMe and SSD so that they are mirrored.  Use two NVMe as Cache1 and two SSD as Cache2 or use the NVMe and SSD you have today as Cache1.  Use btrfs as the file system (keep it simple and avoid ZFS for now).  All cache devices in the same pool are mirrored with btrfs (see below).

 

 

3 hours ago, paokkerkir said:

I'm planning on using the 512gb nvme as cache for appdata/docker etc (with backups daily) and the 240gb ssd for plex cache only.

 

Use one cache for the appdata (docker).  Be sure to use the appdataBackup plugin to back that up.  You don't need daily backups unless the apps you're using change each day.  Use the other cache for file mover.  You don't need to do anything special for plex.  It should be fast enough reading from the HDD (I've never had problems streaming plex from my server).  Use the NVMe cache for file mover and the SSD for the apps that way file transfer is nice and fast.  SSD will be fast enough for the apps.

 

3 hours ago, paokkerkir said:

I get that with Btrfs there are some issues for cache, not sure if this is still the case.

 

Not sure what issues you are talking about.  Been using this for a few years now.

[paokkerkir]

14 hours ago, TimTheSettler said:

Use one cache for the appdata (docker).  Be sure to use the appdataBackup plugin to back that up.  You don't need daily backups unless the apps you're using change each day.  Use the other cache for file mover.  You don't need to do anything special for plex.  It should be fast enough reading from the HDD (I've never had problems streaming plex from my server).  Use the NVMe cache for file mover and the SSD for the apps that way file transfer is nice and fast.  SSD will be fast enough for the apps.

 

I was thinking of using an ssd just for plex metadata, since it is fairly large (over 100gb) and I don't want to allocate that size on my cache nvme.

 

Anyway I'm leaning towards using 2x1tb nvme's for cache and ditching the whole extra ssd for appdata idea.

 

14 hours ago, TimTheSettler said:

Not sure what issues you are talking about.  Been using this for a few years now.

 

I have seen multiple reports of corruption with btrfs for cache; granted these were from 2-3 years back.

[JonathanM]

5 hours ago, paokkerkir said:

I have seen multiple reports of corruption with btrfs for cache

It's still a thing if you

a. have imperfect hardware, BTRFS seems to be less resilient to crashes and such

b. fill the filesystem all the way up. BTRFS gets very upset when it doesn't have room to do its filesystem stuff.

 

b is by far the most common thing we see, improper settings can fill a volume very quickly. Educate yourself on how to adjust where Unraid decides to put data. Be sure you never put yourself in a position to totally fill any single volume or drive.

[TimTheSettler]

5 hours ago, paokkerkir said:

I have seen multiple reports of corruption with btrfs for cache; granted these were from 2-3 years back.

 

3 minutes ago, JonathanM said:

b is by far the most common thing we see, improper settings can fill a volume very quickly.

 

Good to know.  I guess I've been lucky or prudent with my settings.

 

Many people like to use the Mover but I actually turned it off.  My array is used for all my data and my cache is used for appdata.

 

The beauty of unRAID is that you can play around with stuff.  Get started with some simple, basic settings and then tweak things as you go.