I think I may have found a workaround. > One very interesting use of dm-zero is for creating "sparse" devices in conjunction with dm-snapshot. A sparse device reports a device-size larger than the amount of actual storage space available for that device. A user can write data anywhere within the sparse device and read it back like a normal device. Reads to previously unwritten areas will return a zero'd buffer. When enough data has been written to fill up the actual storage space, the sparse device is deactivated. This can be very useful for testing device and filesystem limitations. I don't know if that would be useful for your crypto signature analysis. On Fri, May 11, 2012 at 4:50 PM, Aaron Toponce <aaron.toponce@xxxxxxxxx> wrote: > On Fri, May 11, 2012 at 03:57:24PM -0400, Berke Durak wrote: >> There seems to be a 256 MiB lower limit on device size : mkfs.btrfs >> refuses to create a filesystem on a device that is smaller than that. > > I've noticed the same. I'm interested in researching the patterns the > filesystem puts down on an encrypted container, but would like to use 1MB > files as the block device for the filesystem. Looking for patterns in 256MB > files is too expensive. > > -- > . o . o . o . . o o . . . o . > . . o . o o o . o . o o . . o > o o o . o . . o o o o . o o o -- 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
