On Sun, Nov 25, 2012 at 04:32:08PM +0000, Martin Matuska wrote: > Author: mm > Date: Sun Nov 25 16:32:07 2012 > New Revision: 243524 > URL: http://svnweb.freebsd.org/changeset/base/243524 > > Log: > MFV r243013 and r243267: > > Import the zio nop-write improvement from Illumos. To reduce I/O, > nop-write omits overwriting data if the checksum (cryptographically > secure) of new data matches the checksum of existing data. > It also saves space if snapshots are in use. > > It currently works only on datasets with enabled compression, disabled > deduplication and sha256 checksums. > > IllumOS 13887:196932ec9e6a and 13888:7204b3392a58 > 3236 zio nop-write
This is a nice change, although I don't understand why it depends on compression being turned on. It won't save any space. -- Pawel Jakub Dawidek http://www.wheelsystems.com FreeBSD committer http://www.FreeBSD.org Am I Evil? Yes, I Am! http://tupytaj.pl
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