From 78e51ff1f262696563a6abe0b7e4b603ceb4f995 Mon Sep 17 00:00:00 2001 From: Arshad Hussain Date: Mon, 22 Feb 2021 09:48:40 +0530 Subject: [PATCH] LUDOC-488 fallocate: Add fallocate tuning information This patch adds section on how to tune/enable/disable fallocate for ldiskfs OSTs. Signed-off-by: Arshad Hussain Change-Id: Ic4c2f8cdff188973cfe1aeb9aac322aa3c3bdb69 Reviewed-on: https://review.whamcloud.com/41711 Tested-by: jenkins Reviewed-by: Andreas Dilger --- LustreMaintenance.xml | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/LustreMaintenance.xml b/LustreMaintenance.xml index bfde399..a9b2c5d 100644 --- a/LustreMaintenance.xml +++ b/LustreMaintenance.xml @@ -65,6 +65,9 @@ + + +
@@ -875,6 +878,25 @@ touch: cannot touch ‘test_file’: Read-only file system mds# lctl set_param mdt.fs-MDT0000.readonly=0 mdt.fs-MDT0000.readonly=0</screen> </section> + <section xml:id="lustremaint.tunefallocate" condition="l2E"> + <title><indexterm><primary>maintenance</primary> + <secondary>Tune fallocate</secondary></indexterm> + Tune Fallocate for ldiskfs + This section shows how to tune/enable/disable fallocate for + ldiskfs OSTs. + The default mode=0 is the standard + "allocate unwritten extents" behavior used by ext4. This is by far the + fastest for space allocation, but requires the unwritten extents to be + split and/or zeroed when they are overwritten. + The OST fallocate mode=1 can also be set to use + "zeroed extents", which may be handled by "WRITE SAME", "TRIM zeroes data", + or other low-level functionality in the underlying block device. + mode=-1 completely disables fallocate. + Example: To completely disable fallocate + lctl set_param osd-ldiskfs.*.fallocate_zero_blocks=-1 + Example: To enable fallocate to use 'zeroed extents' + lctl set_param osd-ldiskfs.*.fallocate_zero_blocks=1 +