5:12 a.m.
Sorry for double post but I don't know if this mail has been received.
Hello everyone,
I know this issue was already treated on this mailing list. However none
of the proposed solutions is satisfying me.
Here is my situation : I've got 3 hyperconverged gluster ovirt nodes,
with 6 network interfaces, bounded in bunches of 2 (management, VMs and
gluster). The gluster network is on a dedicated bound where the 2
interfaces are directly connected to the 2 other ovirt nodes. Gluster is
apparently using it :
# gluster volume status vmstore
Status of volume: vmstore
Gluster process TCP Port RDMA Port
Online Pid
------------------------------------------------------------------------------
Brick gluster-ov1:/gluster_bricks
/vmstore/vmstore 49152 0 Y 3019
Brick gluster-ov2:/gluster_bricks
/vmstore/vmstore 49152 0 Y 3009
Brick gluster-ov3:/gluster_bricks
/vmstore/vmstore
where 'gluster-ov{1,2,3}' are domain names referencing nodes in the
gluster network. This networks has 10Gbps capabilities :
# iperf3 -c gluster-ov3
Connecting to host gluster-ov3, port 5201
[ 5] local 10.20.0.50 port 46220 connected to 10.20.0.51 port 5201
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 1.16 GBytes 9.92 Gbits/sec 17 900 KBytes
[ 5] 1.00-2.00 sec 1.15 GBytes 9.90 Gbits/sec 0 900 KBytes
[ 5] 2.00-3.00 sec 1.15 GBytes 9.90 Gbits/sec 4 996 KBytes
[ 5] 3.00-4.00 sec 1.15 GBytes 9.90 Gbits/sec 1 996 KBytes
[ 5] 4.00-5.00 sec 1.15 GBytes 9.89 Gbits/sec 0 996 KBytes
[ 5] 5.00-6.00 sec 1.15 GBytes 9.90 Gbits/sec 0 996 KBytes
[ 5] 6.00-7.00 sec 1.15 GBytes 9.90 Gbits/sec 0 996 KBytes
[ 5] 7.00-8.00 sec 1.15 GBytes 9.91 Gbits/sec 0 996 KBytes
[ 5] 8.00-9.00 sec 1.15 GBytes 9.90 Gbits/sec 0 996 KBytes
[ 5] 9.00-10.00 sec 1.15 GBytes 9.90 Gbits/sec 0 996 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 11.5 GBytes 9.90 Gbits/sec 22
sender
[ 5] 0.00-10.04 sec 11.5 GBytes 9.86
Gbits/sec receiver
iperf Done.
However, VMs stored on the vmstore gluster volume has poor write
performances, oscillating between 100KBps and 30MBps. I almost always
observe a write spike (180Mbps) at the beginning until around 500MB
written, then it drastically falls at 10MBps, sometimes even less
(100KBps). Hypervisors have 32 threads (2 sockets, 8 cores per socket, 2
threads per core).
Here is the volume settings :
Volume Name: vmstore
Type: Replicate
Volume ID: XXX
Status: Started
Snapshot Count: 0
Number of Bricks: 1 x 3 = 3
Transport-type: tcp
Bricks:
Brick1: gluster-ov1:/gluster_bricks/vmstore/vmstore
Brick2: gluster-ov2:/gluster_bricks/vmstore/vmstore
Brick3: gluster-ov3:/gluster_bricks/vmstore/vmstore
Options Reconfigured:
performance.io-thread-count: 32 # was 16 by default.
cluster.granular-entry-heal: enable
storage.owner-gid: 36
storage.owner-uid: 36
cluster.lookup-optimize: off
server.keepalive-count: 5
server.keepalive-interval: 2
server.keepalive-time: 10
server.tcp-user-timeout: 20
network.ping-timeout: 30
server.event-threads: 4
client.event-threads: 8 # was 4 by default
cluster.choose-local: off
features.shard: on
cluster.shd-wait-qlength: 10000
cluster.shd-max-threads: 8
cluster.locking-scheme: granular
cluster.data-self-heal-algorithm: full
cluster.server-quorum-type: server
cluster.quorum-type: auto
cluster.eager-lock: enable
performance.strict-o-direct: on
network.remote-dio: off
performance.low-prio-threads: 32
performance.io-cache: off
performance.read-ahead: off
performance.quick-read: off
auth.allow: *
user.cifs: off
storage.fips-mode-rchecksum: on
transport.address-family: inet
nfs.disable: on
performance.client-io-threads: on
When I naively write directly on the logical volume, which is mounted on
a material RAID5 3-disks array, I have interesting performances:
# dd if=/dev/zero of=a bs=4M count=2048
2048+0 records in
2048+0 records out
8589934592 bytes (8.6 GB, 8.0 GiB) copied, 17.2485 s, 498 MB/s
#urandom gives around 200MBps
Moreover, hypervisors have SSD which have been configured as lvcache,
but I'm unsure how to test it efficiently.
I can't find where is the problem, as every piece of the chain is
apparently doing well ...
Thanks anyone for helping me :)
--
téïcée <https://www.teicee.com/?pk_campaign=Email> *Mathieu Valois*
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