Storage limits per-app

[A Former User]

Is this something that is possible? The use case here is providing testing environments to clients for apps that allow user generated content. This can be useful to make sure a single app does not fill a drive.

[robi]

Sounds like tying it into a quota system.

[A Former User]

@robi Precisely. I could see it in the same resources section. Default could be dynamic (unrestricted) and a user could set it to a discrete value.

[murgero]

@atrilahiji Interesting request and interesting use case - I think it's a neat idea but only for certain apps (mail, lamp, surfer, nextcloud (especially!), and social networks like Mastodon and pixelfed)

Not sure how the implementation would be though

[jdaviescoates]

@murgero @atrilahiji one way I guess this could be done right now would be create an external volume (e.g. a Hetzner Cloud Volume) and use that as the data folder for the app you don't want filling up the primary disk. You can also check the usage of this disk volume in System info.

[A Former User]

@murgero Exactly, I was thinking for stuff like Nextcloud or Moodle specifically.

[girish]

If anyone knows how this can be done on linux, I am open to investigating this. As in how does mount a storage directory into a docker container that has a specific size? I can only think of some (sparse) file based loopback filesystem. I don't like that approach and would prefer some other alternative. I haven't looked into recent developments in linux quota system.

[msbt]

@girish what about https://docs.docker.com/engine/reference/commandline/run/#set-storage-driver-options-per-container (from https://stackoverflow.com/questions/38542426/docker-container-specific-disk-quota)

[robi]

If storage for Apps was integrated with container attached storage from MayaData.com, this would be an easier option.

This will also help Apps be more distributed and clustered, among other benefits.

[MooCloud_Matt]

@girish
it can be done with LVM, btrfs or ZFS.
And their relative Docker driver, can be an option with an installation on ubuntu + one of those FS.

[MooCloud_Matt]

@robi said in Storage limits per-app:

MayaData.com

I think they use OpenEBS, and as all the distributed storage solutions are complicated to set up, we use Ceph and need a dedicated port on the cluster server for the sync job, not as a requirement but as a need for reasonable performance to be able to use there features.

[girish]

@msbt Interesting link, thanks. I wonder if it works for volumes also. It says it depends on the "volume plugin". Have to investigate. On Cloudron, the data directory is just a normal volume and doesn't use any plugin and it's unclear if that standard thing supports storage-opt.

[robi]

@moocloud_matt said in Storage limits per-app:

OpenEBS

Yes, but there is a more advanced version at MayaData.

@staff and I have spoken with them before.

[Aizat]

Any news about this? This is very useful especially if we're giving access to our clients who may overuse the storage in some of the apps on Cloudron.

[girish]

@Aizat Still looking for suggestions to my comment https://forum.cloudron.io/topic/5103/storage-limits-per-app/7

[girish]

Maybe we have use usrquota - https://www.digitalocean.com/community/tutorials/how-to-set-filesystem-quotas-on-ubuntu-18-04 . I guess this involves creating a user per app.

XFS has pquota - https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_file_systems/assembly_limiting-storage-space-usage-on-xfs-with-quotas_managing-file-systems . EXT4 has prjquota - https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_file_systems/assembly_limiting-storage-space-usage-on-ext4-with-quotas_managing-file-systems

Also, found that there is a --storage-size when using XFS in Docker - https://docs.docker.com/engine/reference/commandline/run/#set-storage-driver-options-per-container

[robi]

This was also addressed in OpenEBS - https://github.com/openebs/dynamic-localpv-provisioner/issues/13

[girish]

@robi Nice find, looks like they implemented this as XFS only. Most VPS providers use EXT4 by default afaik.

[robi]

@girish It does not matter that VPS providers use as you control what happens inside containers.

If you choose to attach container volumes they can be XFS layers with all the nice tools XFS comes with, which EXT4 lacks.

Similarly for attaching external volumes of additional space apart from the default FS the OS is installed on.

[girish]

@robi the volumes can be XFS, but it requires a backing device. On a standard VPS, this means that we have to create a (big enough) file on EXT4 file system and then format it as XFS. This setup has the usual issues of loopback devices - what size this initial file should be, how to resize it live to increase/decrease storage etc. Not sure how well this performs either.