[mythtv-users] Unionfs [was: Multiple Directories for Recordings]

Lincoln Dale ltd at interlink.com.au
Fri Sep 22 10:02:02 UTC 2006

> I've been playing with unionfs as a way of merging multiple directories
> into
> one. It's available in Debian testing in the unionfs-modules-2.6.17-2-686
> package now that 2.6.17 is the kernel.

unionfs has been around for a while.  while i haven't tracked linux-kernel
recently, it was previously in a state where linux-vfs folks wouldn't accept

> The advantages would be:
> *) Works with unpatched MythTV.

well - not as if patching mythtv is hard. :)
i run all sorts of custom patches anyhow.

> *) Losing a disk will just lose the recordings on that disk.

the patch in trac ticket #1744 also means this.

> *) Migration from the original single disk doesn't require reformatting
> the > original disk.

neither does the patch in trac ticket #1744

> But these things stop me using it:
> *) All new files get put in the first writeable branch.

the trac patch in ticket #1744 will write across all directories.

> *) I don't know what happens when the first branch fills up (autoexpire
> won't help if other branches have space).

the trac patch in ticket #1744 won't break auto-expire.

> *) Can't move files from one branch to another without unmounting the
> union.
> That requires shutting down all of Myth.

no shutdown of myth is necessary.  the only clueful thing is to avoid moving
a file as it is being written to or read from.. not exactly too hard..

> *) Deletion only supports "whiteout" mode so you end up with a .wh file
> for every file ever created. Not sustainable.

sounds like you _should_ be running my patch. :)

> root at hal:/tmp# df -h
> Filesystem            Size  Used Avail Use% Mounted on
> unionfs               324G  257G   65G  80% /dev/shm/tmp/store

well - here i just have RecordFilePrefix set to

# df -k
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/hdc1            307663800 256848532  50815268  84% /media1
/dev/hda5            159963408  18832852 141130556  12% /media2
/dev/hdb1            192292124 182551740   9740384  95% /media3
/dev/sda1            292994784 243960524  49034260  84% /media4
/dev/sdb1            292994784 243565088  49429696  84% /media5



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