[LSF/MM/BPF TOPIC] Enhancing Linux Copy Performance and Function and improving backup scenarios

[Steve French]

As discussed last year:

Current Linux copy tools have various problems compared to other
platforms - small I/O sizes (and most don't allow it to be
configured), lack of parallel I/O for multi-file copies, inability to
reduce metadata updates by setting file size first, lack of cross
mount (to the same file system) copy optimizations, limited ability to
handle the wide variety of server side copy (and copy offload)
mechanisms and error handling problems.   And copy tools rely less on
the kernel file system (vs. code in the user space tool) in Linux than
would be expected, in order to determine which optimizations to use.

But some progress has been made since last year's summit, with new
copy tools being released and improvements to some of the kernel file
systems, and also some additional feedback on lwn and on the mailing
lists.  In addition these discussions have prompted additional
feedback on how to improve file backup/restore scenarios (e.g. to
mounts to the cloud from local Linux systems) which require preserving
more timestamps, ACLs and metadata, and preserving them efficiently.

Let's continue our discussions from last year, and see how we can move
forward on improving the performance and function of Linux fs
(including the VFS and user space tools) for various backup, restore
and copy scenarios operations.