afr: add new value for read-hash-mode volume option

Updates: #363

This new value (3) will try to wind read requests to the child of AFR
having the least amount of pending requests in its queue.

Change-Id: If6bda2aac9bf7aec3fc39622f78659313c4b6508
Signed-off-by: Ravishankar N <ravishankar@redhat.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/tests/basic/afr/afr-read-hash-mode.t b/tests/basic/afr/afr-read-hash-mode.t
new file mode 100644
index 00000000000..eeff10d8ebd
--- /dev/null
+++ b/tests/basic/afr/afr-read-hash-mode.t
@@ -0,0 +1,56 @@
+#!/bin/bash
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+
+cleanup
+
+function reads_brick_count {
+        $CLI volume profile $V0 info incremental | grep -w READ | wc -l
+}
+
+TEST glusterd
+TEST pidof glusterd
+TEST $CLI volume create $V0 replica 3 arbiter 1 $H0:$B0/${V0}{0..2}
+
+TEST $CLI volume set $V0 cluster.choose-local off
+TEST $CLI volume set $V0 performance.quick-read off
+TEST $CLI volume set $V0 performance.io-cache off
+TEST $CLI volume set $V0 performance.write-behind off
+TEST $CLI volume set $V0 performance.stat-prefetch off
+TEST $CLI volume set $V0 performance.read-ahead off
+TEST $CLI volume start $V0
+
+# Disable all caching
+TEST glusterfs --entry-timeout=0 --attribute-timeout=0 -s $H0 --volfile-id $V0 $M0
+TEST dd if=/dev/urandom of=$M0/FILE bs=1M count=8
+EXPECT_WITHIN $UMOUNT_TIMEOUT "Y" force_umount $M0
+
+# TEST if the option gives the intended behavior. The way we perform this test
+# is by performing reads from the mount and write to /dev/null. If the
+# read-hash-mode is 3, then for a given file, more than 1 brick should serve the
+# read-fops where as with the default read-hash-mode (i.e. 1), only 1 brick will.
+
+# read-hash-mode=1
+TEST glusterfs --entry-timeout=0 --attribute-timeout=0 -s $H0 --volfile-id $V0 $M0
+EXPECT "1" mount_get_option_value $M0 $V0-replicate-0 read-hash-mode
+TEST $CLI volume profile $V0 start
+TEST dd if=$M0/FILE of=/dev/null bs=1M
+count=`reads_brick_count`
+TEST [ $count -eq 1 ]
+EXPECT_WITHIN $UMOUNT_TIMEOUT "Y" force_umount $M0
+
+# read-hash-mode=3
+TEST glusterfs --entry-timeout=0 --attribute-timeout=0 -s $H0 --volfile-id $V0 $M0
+TEST $CLI volume set $V0 cluster.read-hash-mode 3
+EXPECT_WITHIN $CONFIG_UPDATE_TIMEOUT "3" mount_get_option_value $M0 $V0-replicate-0 read-hash-mode
+TEST $CLI volume profile $V0 info clear
+TEST dd if=$M0/FILE of=/dev/null bs=1M
+count=`reads_brick_count`
+TEST [ $count -eq 2 ]
+
+# Check that the arbiter did not serve any reads
+arbiter_reads=$($CLI volume top $V0 read brick $H0:$B0/${V0}2|grep FILE|awk '{print $1}')
+TEST [ -z $arbiter_reads ]
+
+cleanup;