staggered stripes

[Russell Coker <russell@coker.com.au>]

http://www.cs.wisc.edu/adsl/Publications/corruption-fast08.html

Page 13 of the above paper says:

# Figure 12 presents for each block number, the number of disk drives of disk
# model ‘E-1’ that developed a checksum mismatch at that block number. We see
# in the figure that many disks develop corruption for a specific set of block
# numbers. We also verified that (i) other disk models did not develop
# multiple check-sum mismatches for the same set of block numbers (ii) the
# disks that developed mismatches at the same block numbers belong to
# different storage systems, and (iii) our software stack has no specific data
# structure that is placed at the block numbers of interest.
#
# These observations indicate that hardware or firmware bugs that affect
# specific sets of block numbers might exist. Therefore, RAID system designers
# may be well-advised to use staggered stripes such that the blocks that form
# a stripe (providing the required redundancy) are placed at different block
# numbers on different disks.

Does the BTRFS RAID functionality do such staggered stripes?  If not could it 
be added?

I guess there's nothing stopping a sysadmin from allocating an unused 
partition at the start of each disk and use a different size for each disk.  
But I think it would be best to do this inside the filesystem.

Also this is another reason for having DUP+RAID-1.

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