On Mon, Jun 05, 2006 at 09:49:10AM +0300, Jan Wagner wrote:
> I saw with the logdev parameter it is possible to specify an external log
> device on a separate disk and partition.
> What would be even more interesting for my special purposes is whether
> even the file system structure (inodes etc) could be placed on a
> different disk?
The realtime subvolume will indeed give you this split. See xfs(5)
and mkfs/xfs(8) where most doco resides on this.
> Rationale being, when one wants to build a data recorder like a
> Linux personal video recorder that is using A/V harddisks (ATA Streaming
> Feature Set, or SmoothStream), one could use the A/V disk with A/V
> streaming enabled to unreliably(!) write or read all the user data, and a
> second disk to reliably store the actual log and file system structure on.
> Yes, there is alreayd the realtime subvolume in XFS, but can it tolerate
> unreliable A/V read/write? (i.e., where drive has been told to disable
> and skip all read error correction and write verification?)
Not 100% sure what unreliable means here from a software POV... would
we be seeing errors at the filesystem layer on IOs to/from the driver?
If not, I think it would work just fine.