features/shard: Make lru limit of inode list configurable

Currently this lru limit is hard-coded to 16384. This patch makes it
configurable to make it easier to hit the lru limit and enable testing
of different cases that arise when the limit is reached.

The option is features.shard-lru-limit. It is by design allowed to
be configured only in init() but not in reconfigure(). This is to avoid
all the complexity associated with eviction of least recently used shards
when the list is shrunk.

Change-Id: Ifdcc2099f634314fafe8444e2d676e192e89e295
updates: bz#1605056
Signed-off-by: Krutika Dhananjay <kdhananj@redhat.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/tests/bugs/shard/configure-lru-limit.t b/tests/bugs/shard/configure-lru-limit.t
new file mode 100644
index 00000000000..a8ba8ed8509
--- /dev/null
+++ b/tests/bugs/shard/configure-lru-limit.t
@@ -0,0 +1,48 @@
+#!/bin/bash
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+cleanup
+
+TEST glusterd
+TEST pidof glusterd
+TEST $CLI volume create $V0 replica 3 $H0:$B0/${V0}{0,1,2}
+TEST $CLI volume set $V0 features.shard on
+TEST $CLI volume set $V0 features.shard-block-size 4MB
+TEST $CLI volume set $V0 features.shard-lru-limit 25
+TEST $CLI volume start $V0
+
+TEST $GFS --volfile-id=$V0 --volfile-server=$H0 $M0
+
+# Perform a write that would cause 25 shards to be created, 24 of them under .shard
+TEST dd if=/dev/zero of=$M0/foo bs=1M count=100
+
+statedump=$(generate_mount_statedump $V0)
+sleep 1
+EXPECT "25" echo $(grep "lru-max-limit" $statedump | cut -f2 -d'=' | tail -1)
+
+# Base shard is never added to this list. So all other shards should make up for 24 inodes in lru list
+EXPECT "24" echo $(grep "inode-count" $statedump | cut -f2 -d'=' | tail -1)
+
+rm -f $statedump
+
+# Test to ensure there's no "reconfiguration" of the value once set.
+TEST $CLI volume set $V0 features.shard-lru-limit 30
+statedump=$(generate_mount_statedump $V0)
+sleep 1
+EXPECT "25" echo $(grep "lru-max-limit" $statedump | cut -f2 -d'=' | tail -1)
+rm -f $statedump
+
+EXPECT_WITHIN $UMOUNT_TIMEOUT "Y" force_umount $M0
+
+TEST $GFS --volfile-id=$V0 --volfile-server=$H0 $M0
+statedump=$(generate_mount_statedump $V0)
+sleep 1
+EXPECT "30" echo $(grep "lru-max-limit" $statedump | cut -f2 -d'=' | tail -1)
+rm -f $statedump
+
+EXPECT_WITHIN $UMOUNT_TIMEOUT "Y" force_umount $M0
+TEST $CLI volume stop $V0
+TEST $CLI volume delete $V0
+
+cleanup