This “read-only file system” error was not evidence that the new RAID5 array itself had become read-only. IceWhale identified the actual problem: the Plex host path was wrong. The user used /Cube-Storage/Media instead of the mounted storage path /media/Cube-Storage/Media.
That distinction matters because ZimaOS keeps its system root protected. A bad absolute path can make an app try to create a directory under the OS root and produce a misleading read-only error.
The App Was Pointing at the Wrong Host Path
/Cube-Storage/Media as a host path instead of the mounted storage path expected by ZimaOS. Source: IceWhale Community Forum.The path looked logical because it came from the Files UI, but it was missing the host mount prefix required by the app definition at that time.
Why ZimaOS Returned a Read-Only Error
/Cube-Storage under the read-only system root and failed. Source: IceWhale Community Forum.When Docker tried to create /Cube-Storage at the host root, it hit the read-only system filesystem. That is different from a real storage-pool fault where an already-mounted filesystem has remounted itself read-only after I/O or filesystem errors.
Use Current App Storage Paths Instead of Guessing
The current ZimaOS app data paths explains that app data and media are mapped from real storage folders into container paths.
If the copied path in Files differs from the path shown in the app’s volume picker, use the supported storage picker or verify the real host mount before editing the app.
How to Tell a Path Error From a Real Read-Only Volume
If Files can still create folders on the storage pool but only one Docker app gets a read-only error, suspect the mapping first. If Files itself cannot write and the mount is reported read-only at the OS level, use filesystem/storage diagnostics instead.
The read-only volume checklist covers the second case.
Bottom Line
The thread has a clear official diagnosis: the path was wrong. Before repairing RAID or changing permissions, verify whether the app is pointing to the real mounted storage path. A wrong absolute path can make healthy storage look like a read-only filesystem problem.
