From e1c330759c4b6fda73b8454458d555f09db24090 Mon Sep 17 00:00:00 2001 From: Craig Rodrigues Date: Sun, 22 Dec 2013 10:58:40 +0000 Subject: [PATCH] Mention ZFS zio nop-write improvement. --- release/doc/en_US.ISO8859-1/relnotes/article.xml | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/release/doc/en_US.ISO8859-1/relnotes/article.xml b/release/doc/en_US.ISO8859-1/relnotes/article.xml index a309e516719c..05ca69e5f2e5 100644 --- a/release/doc/en_US.ISO8859-1/relnotes/article.xml +++ b/release/doc/en_US.ISO8859-1/relnotes/article.xml @@ -342,6 +342,14 @@ Support for L2ARC compression has been added to ZFS. + The zio nop-write improvement from Illumos + was imported into &os;. To reduce I/O, nop-write skips 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. This improvement only works only on + datasets with enabled compression, disabled deduplication and + sha256 checksums. + ZFS will now compare the checksums of incoming writes to the checksum of the existing on-disk data and avoid issuing any write I/O for data that has not changed. This will reduce I/O