On Saturday 30 January 2010, Goffredo Baroncelli wrote: > On Saturday 30 January 2010, 0bo0 wrote: > > > Is the goal NOT to accurately represent the actual available space? > > Seems rather odd that users are simply to know/accept that "available > > space" in btrfs RAID-10 != "available space" in md RIAD-10 ... > > As reported more time in this ML, btrfs is able to store the data in > striping/raid1 mode per-file-basis. > > The space on the disk is grouped in chunk. The raid mode is set per-chunk- > basis [1]. So a file stored in a chunk may be written two times (in one or two > different disk), and another file stored in another chunk may be written with > a different policy.
Sorry, I forgot the reference: [1] http://btrfs.wiki.kernel.org/index.php/Multiple_Device_Support > > In fact the btrfs store the data in "raid0" mode, and the metadata in raid1 > mode, even with only one disk. Even tough the words "raid1/0" are incorrect > with only one disk. > > So key points are: > - it is incorrect to say that the btrfs filesystem is configured in raidX mode > - it is correct that the file xyz is stored in raidX mode > - is quite simple to evaluate the space available. It is more complex to > evaluate before the file creation how many of the space available a file of a > certain size consumes. > - unfortunately, today are not available tools that permits to manage the raid > mode of a file > > BR > G.Baroncelli > > > > -- > gpg key@ keyserver.linux.it: Goffredo Baroncelli (ghigo) <kreijack inwind it> > Key fingerprint = 4769 7E51 5293 D36C 814E C054 BF04 F161 3DC5 0512 > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- gpg key@ keyserver.linux.it: Goffredo Baroncelli (ghigo) <kreij...@inwind.it> Key fingerprint = 4769 7E51 5293 D36C 814E C054 BF04 F161 3DC5 0512 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
