'Other' can be stuff associated with Windows or NTFS, not necessarily DrivePool itself. Would be nice to have a way to get a list of the files or some details.
I would try moving some files to a non-pooled drive, then move them back. See if the 'other' amount goes down.
I found this elsewhere on the forum...
And then there's "Other". "Other" always confuses people, but it literally is everything else.
So what else is there?
Non-pooled files that exist on that disk. Remember that just because a disk is part of the pool doesn't mean that you can't continue to use that disk to store non-pooled files.
NTFS Metadata. For every file on a NTFS volume, there is additional metadata associated with that data stream, like the file name, file attributes, modification times, etc. These typically take very little disk space, but can add up if you have lots of files.
Directory entries. On NTFS, directory entries are actually stored as regular files with a "directory" attribute. But instead of a data stream, they contain a little database of index entries for each file (and subdirectory) that exists under them.
Slack space. Just because you have a 100GB volume, doesn't mean that you can use all 100 Gigabytes of that volume to store data. NTFS divides your volume into equally sized chunks called clusters, which are typically 4096 bytes in size. If your file doesn't fit neatly into these clusters then there's going to be some space at the end of the file that's wasted. We call this "slack space".
For example, if you have a 2kb text file, it's going to use the full 4kb cluster, even if 2kb is empty space. Same goes with larger files that don't fill that last cluster, which is very common.