On Fri, Dec 07, 2012 at 03:04:57PM -0600, Stan Hoeppner wrote: > On 12/7/2012 4:16 AM, Dave Chinner wrote: > > On Thu, Dec 06, 2012 at 03:29:33AM -0600, Stan Hoeppner wrote: > >> On 12/5/2012 9:01 PM, Jeffrey Ellis wrote: > >> BTW, if your goal in all of this is simply copying all the directories > >> and files from one disk to another disk, you could have used "cp -a" and > >> been done already. It takes longer to execute than xfsdump/xfsrestore, > >> but given you've been at this for many days now, "cp -a" would have > >> already completed--long ago. > > > > Unfortunately, using cp or rsync is not possible because the > > filesystem has a real-time device attached to it. It's basically a > > ~10GB data device and a ~500GB real-time device. I'd say it's from a > > DVR or something like that, and that Jeffrey is trying to put > > a bigger disk in the DVR.... > > Ah, yes. I didn't catch the RT volume. > > Incidentally, since the real-time feature has never been fully supported > under Linux, why are DVR manufacturers even using it? Without GRIO and > the XBOW ASIC the real-time volume is pretty much useless isn't it? The realtime volume actually has nothing to do with "real-time" at all. What it has is a deterministic allocator (bitmap rather than tree based) which is what you need for real-time applications (i.e. bound worst case performance). It got called the "real-time device" because of the applications it was used for, not because there is anything "real-time" about it. IOWs, you don't need special hardware to take advantage of the properties of the allocator. DVR manufacturers have decided to use it for 3 reasons: 1. Folklore says you need a RT device for concurrent streaming workloads 2. It's supported upstream 3. It makes it hard for windows users to replace the harddisk in the DVR by themselves (true). #3 is the case we are seeing here. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
