RClone - Overview
Overview of Cloud Storage Systems
Each cloud storage system is slighly different. Rclone attempts to provide a unified interface to them, but some underlying differences show through.
Here is an overview of the major features of each cloud storage system:
|Name||Hash||ModTime||Case Insensitive||Duplicate Files|
|Google Cloud Storage||MD5||Yes||No||No|
|Amazon Cloud Drive||MD5||No||Yes||No|
|Microsoft One Drive||SHA1||Yes||Yes||No|
|The Local Filesystem||All||Yes||Depends||No|
The cloud storage system supports various hash types of the objects. The hashes are used when transferring data as an integrity check and can be specifically used with the --checksum flag in syncs and in the check command.
To use the checksum checks between filesystems they must support a common hash type.
The cloud storage system supports setting modification times on objects. If it does then this enables a using the modification times as part of the sync. If not then only the size will be checked by default, though the MD5SUM can be checked with the --checksum flag.
All cloud storage systems support some kind of date on the object and these will be set when transferring from the cloud storage system.
If a cloud storage systems is case sensitive then it is possible to have two files which differ only in case, eg file.txt and FILE.txt. If a cloud storage system is case insensitive then that isn’t possible.
This can cause problems when syncing between a case insensitive system and a case sensitive system. The symptom of this is that no matter how many times you run the sync it never completes fully.
The local filesystem may or may not be case sensitive depending on OS.
Windows - usually case insensitive, though case is preserved OSX - usually case insensitive, though it is possible to format case sensitive Linux - usually case sensitive, but there are case insensitive file systems (eg FAT formatted USB keys) Most of the time this doesn’t cause any problems as people tend to avoid files whose name differs only by case even on case sensitive systems.
If a cloud storage system allows duplicate files then it can have two objects with the same name.
This confuses rclone greatly when syncing - use the rclone dedupe command to rename or remove duplicates.