When do file ids/inodes change for files in a pool?

[Pafegori]

Hi, I am using a software which identifies files by it's unique file id/inode. I have been recording file id changes of files in my pool over the last year and noticed that the file id changes every few weeks or so (around 20 times duing the last year) for files which I didn't (manually) copy/move. I could imagine that a balancing move changes it, but that shouldn't happen that often in my setup.

Could you shed some light on how these files ids are created in the first place and what's the reason for changes. Thank you!

[Christopher (Drashna)]

Which software are you using? 

And in theory, it shouldn't. 

[Pafegori]

I am using some self-written Python scripts with `os.stat` which on Windows uses `GetFileInformationByHandle` to get `nFileIndexHigh` and `nFileIndexLow`.

How does drivepool create these values? If it passes through the original values, which ones takes priority if there are more than 1 copy?

[Pafegori]

Hi, is it possible to get more information on this?
I still get changing file indices and I would like to know how these are created by DrivePool and in which situtations they can change.

[Shane]

This thread by MitchC goes into the file indexing issues with DrivePool.

TLDR is DrivePool currently generates its own file index table for files opened from the pool, held in RAM, with each file being assigned an ID incrementing from zero as they are opened (edit: the first time after each boot), renamed or moved within the pool, which is not how NTFS does it (a file should retain its FileID regardless of being renamed or moved within a volume and do so regardless of reboots), which means until this is fixed any program that assumes normal FileID behaviour from a pool drive (because DrivePool presents the pool as a NTFS volume) may behave in an unplanned manner.

[Pafegori]

Thanks for your reply. This is indeed bad and will confuse (or at least drastically reduce performance) of my backup software.

[JC_RFC]

I am also seeing this behaviour and it affects performance greatly of Freefilesync. This software uses fileid to track moved files and keep folders in sync.

When I move some files on the drivepool (or rename them) the fileid changes on the Drivepool. This does not happen for any of my normal or networked drives which maintain the fileid for moves, renames etc.

The result is that if i move say 100GB of data on my drivepool from one folder to another (or rename a large group of files) when I run freefilesync for backup instead of mirroring the file moves or renames it needs to delete and recopy every moved or renamed file. Over the network this can take hours instead of less than a second so the impact is substantial.