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authorColin Percival <cperciva@FreeBSD.org>2015-07-30 04:01:00 +0000
committerColin Percival <cperciva@FreeBSD.org>2015-07-30 04:01:00 +0000
commita5c1653b5c48a9d59acc372d500d6a79abec019d (patch)
tree17b26e0f733e7b23c95ef2bfeca77e509071909e /release/tools/ec2.conf
parentaaebf690629431093f467ed6c2ddd181a4336749 (diff)
downloadsrc-a5c1653b5c48a9d59acc372d500d6a79abec019d.tar.gz
src-a5c1653b5c48a9d59acc372d500d6a79abec019d.zip
Disable blkif indirect segment I/Os in EC2 by default due to performance
issues on some EC2 instance types. Users may want to experiment with removing this from loader.conf and measuring the performance impact on the EC2 instances they are using.
Notes
Notes: svn path=/head/; revision=286063
Diffstat (limited to 'release/tools/ec2.conf')
-rw-r--r--release/tools/ec2.conf5
1 files changed, 5 insertions, 0 deletions
diff --git a/release/tools/ec2.conf b/release/tools/ec2.conf
index 9472ec59d89f..557e60260dbf 100644
--- a/release/tools/ec2.conf
+++ b/release/tools/ec2.conf
@@ -70,6 +70,11 @@ vm_extra_pre_umount() {
# nodes, but apply the workaround just in case.
echo 'hw.broken_txfifo="1"' >> ${DESTDIR}/boot/loader.conf
+ # Some EC2 instances suffer a significant (~40%) reduction in
+ # throughput when using blkif indirect segment I/Os. Disable this
+ # by default for now.
+ echo 'hw.xbd.xbd_enable_indirect="0"' >> ${DESTDIR}/boot/loader.conf
+
# The first time the AMI boots, the installed "first boot" scripts
# should be allowed to run:
# * ec2_configinit (download and process EC2 user-data)