question about drive for "docker / plugins"

[niven]

Hello.

 

I'm thinking about upgrading to unraid v6 from 5 soon. I took a look and the new features look really cool. I would like to use docker and install apps like couchpotato, sickbeard etc. I red on the docker guide that you should either use your cache drive or a data drive. I would like to create a designated "docker/app" drive on my server. Can this simply be done by selecting a data drive and follow the docker guide instructions? Also how much space do you recommend for this kind of use?

Does anybody recommend some specific drives to do this job SSD or HDD?

 

any tips appreciated

[trurl]

Hello.

 

I'm thinking about upgrading to unraid v6 from 5 soon. I took a look and the new features look really cool. I would like to use docker and install apps like couchpotato, sickbeard etc. I red on the docker guide that you should either use your cache drive or a data drive. I would like to create a designated "docker/app" drive on my server. Can this simply be done by selecting a data drive and follow the docker guide instructions? Also how much space do you recommend for this kind of use?

Does anybody recommend some specific drives to do this job SSD or HDD?

 

any tips appreciated

If you use a data drive, that is, a drive that is part of the parity-protected array, docker is likely to keep both that drive and the parity drive active because the dockers will need to write to it, and any writes to a parity-protected drive must also write parity. This is the main reason most people put both the docker img and any appdata used by individual containers on the cache drive.

 

Do you already have a cache drive? That is probably the simplest way to go.

 

Another approach is to use the Unassigned Devices plugin to manage a drive that is not part of the array, and use that for dockers.

[niven]

hi trurl, thanks for the reply.

 

If you use a data drive, that is, a drive that is part of the parity-protected array, docker is likely to keep both that drive and the parity drive active because the dockers will need to write to it, and any writes to a parity-protected drive must also write parity. This is the main reason most people put both the docker img and any appdata used by individual containers on the cache drive.

 

Aha, ok I see the advantage of using a cache drive for this now. I currently don't have a cache drive on my server, but i have been thinking about getting one for a while--

I will probably get a cache drive and use it with docker. is there a size thats reccomended for a cache drive? I understand you need to have enough space to handle the daily transfer amount you do to the server, but would a SSD be the way to go? (i'm thinking something cheap max 120gb)

[itimpi]

I will probably get a cache drive and use it with docker. is there a size thats reccomended for a cache drive? I understand you need to have enough space to handle the daily transfer amount you do to the server, but would a SSD be the way to go? (i'm thinking something cheap max 120gb)

This is one of those questions that has no hard-and-fast answer because it can vary so much from user to user.

 

Things you need to allow for are:

• largest amount of files you ever want cached.  Note that if you exceed this then writes start bypassing the cache so it is not fatal if you allow too little.    You should add to this the size of the largest file you are likely to transfer as this is then set as the 'Min Free Space' setting
  
• An allowance for Docker if you are going to use it.  About 10-20G for this is plenty.    However if any apps you want to run under Docker need space on the cache for files they download then you have to allow for this
  
• Are you going to run VM's?  If so then you need to allow for their virtual disk files.  The amount would depend on the type and size of the VM's
  

I would think that 120GB is probably more than enough for the first requirement.  It might also cover the second one depending on the apps you want to run under Docker.  If you get into VM's (particularly Windows ones) then you are likely to need more space (however this could be added later).

[trurl]

hi trurl, thanks for the reply.

 

If you use a data drive, that is, a drive that is part of the parity-protected array, docker is likely to keep both that drive and the parity drive active because the dockers will need to write to it, and any writes to a parity-protected drive must also write parity. This is the main reason most people put both the docker img and any appdata used by individual containers on the cache drive.

 

Aha, ok I see the advantage of using a cache drive for this now. I currently don't have a cache drive on my server, but i have been thinking about getting one for a while--

I will probably get a cache drive and use it with docker. is there a size thats reccomended for a cache drive? I understand you need to have enough space to handle the daily transfer amount you do to the server, but would a SSD be the way to go? (i'm thinking something cheap max 120gb)

After you add a cache drive, on each user share page there is a setting for how it uses cache. The choices are Yes, No, and Only. Many people create an appdata share for their dockers and other apps, and set it to cache-only. If you don't make it Only, mover will move it to the other disks and it will break your apps.

 

Many of the docker templates are preconfigured to use /mnt/cache/appdata, which is where unRAID sees a share named appdata on the cache drive.

 

It is not necessary to cache writes to any shares, I don't. I have an appdata and a VM share set to cache-only. All my other shares are set to not use cache. I only have 120GB SSD for cache. Actually, I have 2x120GB SSD as btrfs raid1 cache pool so I get redundancy there also.

 

I don't care how fast writes to other shares are because most of that writing is automated backups and downloads, mostly in the middle of the night, so I just write them directly to parity-protected drives.

[niven]

Ok thanks for the information guys!

 

re you going to run VM's?  If so then you need to allow for their virtual disk files.  The amount would depend on the type and size of the VM's

 

Not at the moment, but i might look into it later. (need to get more experience before i start doing the advanced stuff hehe.) I will start of with docker, and use the plugins like; nzbget, sonarr and couchpotato. I have been using a raspberry Pi to download and distribute media to my unraid server for a while, but it is slow compared to what the unraid server can do.

 

After you add a cache drive, on each user share page there is a setting for how it uses cache. The choices are Yes, No, and Only. Many people create an appdata share for their dockers and other apps, and set it to cache-only. If you don't make it Only, mover will move it to the other disks and it will break your apps.

 

Many of the docker templates are preconfigured to use /mnt/cache/appdata, which is where unRAID sees a share named appdata on the cache drive.

 

It is not necessary to cache writes to any shares, I don't. I have an appdata and a VM share set to cache-only. All my other shares are set to not use cache. I only have 120GB SSD for cache. Actually, I have 2x120GB SSD as btrfs raid1 cache pool so I get redundancy there also.

 

I don't care how fast writes to other shares are because most of that writing is automated backups and downloads, mostly in the middle of the night, so I just write them directly to parity-protected drives.

 

Great info and tips thanks! Will use this when i decide to install a cache drive to my server.