deadhorseconsulting posted on Tue, 19 Nov 2013 13:24:01 -0600 as excerpted: > Interesting, this confirms what I was observing. > Given the wording in man pages for "-m" and "-d" which states "Specify > how the metadata or data must be spanned across the devices specified." > I took "devices specified" to literally mean the devices specified after > the according switch. It's all in how you read the documentation. After years of doing so... While I can see how you might get that from reading the -m and -d option text descriptions, the synopsis indicates differently (excerpt quotes reformatted for posting): SYNOPSIS mkfs.btrfs [ -A alloc-start ] [ -b byte-count ] [ -d data-profile ] [ -f ] [ -n node‐size ] [ -l leafsize ] [ -L label ] [ -m metadata profile ] [ -M mixed data+metadata ] [ -s sectorsize ] [ -r rootdir ] [ -K ] [ -O feature1,feature2,... ] [ -h ] [ -V ] device [ device ... ] Here, you can see that the -d and -m options take only a single parameter, the profile, and that the device list goes at the end and is thus a general device list, not specifically linked to the -d and -m options. Similarly, the option lines themselves: -d, --data type -m, --metadata profile ... not... -d, --data type [ device [ device ... ]] -m, --metdata profile [ device [ device ...]] Those are from the manpage. Similarly, the usage line from the output of mkfs.btrfs --help (--help being an unrecognized option it says, but it does what it needs to do...): usage: mkfs.btrfs [options] dev [ dev ... ] options: -d --data data profile, raid0, raid1, raid5, raid6, raid10, dup or single -m --metadata metadata profile, values like data profile All options come first, no indication of per-option device list, then the general purpose devices list. So I'd argue that the documentation's reasonably clear as-is, no per- option device list, general purpose device list at the end, thus no ability to specify data-specific and metadata-specific device lists. (Of course it can happen that the code gets out of sync with the documentation, but that wasn't the argument here.) -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
