adrian cockcroft writes:
 > Why can't you adapt ZFS for swap? It does the transactional clustering of
 > random writes into sequential related blocks, aggressive prefetch on read,
 > and would also guard against corrupt blocks in swap. Anon-ZFS?
 > Adrian

Good point. And It works already, swap to a zvol 

        http://blogs.sun.com/scottdickson/entry/fun_with_zvols_-_swap
        ZFS admin guide (currently down): 
http://docs.sun.com/app/docs/doc/819-5461/6n7ht6qsl?a=view

For output ZFS will get streaming perf  out of the disks and
as you  say will order pages from a  given object (an anon segment?)

For swapin, I don't think we'll trigger read ahead (zfetch
code) but the low level vdev prefetch could be activated. The
heuristic was recently adjusted so that it won't trigger on
data blocks. We might need to revisit this for zvol/swap case.

-r

PS. I would set up the zvol to use volblocksize == pagesize.




 > Why can't you adapt ZFS for swap? It does the transactional clustering 
 > of random writes into sequential related blocks, aggressive prefetch on 
 > read, and would also guard against corrupt blocks in swap. Anon-ZFS?<div><br 
 > class="webkit-block-placeholder">
 > </div><div>Adrian</div>

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