Am 18.02.2015 um 23:26 schrieb Ben Turner:
----- Original Message -----
From: "Lars Hanke" <deb...@lhanke.de>
To: "Ben Turner" <btur...@redhat.com>
Cc: gluster-users@gluster.org
Sent: Wednesday, February 18, 2015 5:09:19 PM
Subject: Re: [Gluster-users] Poor Gluster performance
Am 18.02.2015 um 22:05 schrieb Ben Turner:
----- Original Message -----
From: "Lars Hanke" <deb...@lhanke.de>
To: gluster-users@gluster.org
Sent: Wednesday, February 18, 2015 3:01:54 PM
Subject: [Gluster-users] Poor Gluster performance
I set up a distributed, replicated volume consisting of just 2 bricks on
two physical nodes. The nodes are peered using a dedicated GB ethernet
and can be accessed from the clients using a separate GB ethernet NIC.
Doing a simple dd performance test I see about 11 MB/s for read and
write. Running a local setup, i.e. both bricks on the same machine and
local mount, I saw even 500 MB/s. So network sould be the limiting
factor. But using NFS or CIFS on the same network I see 110 MB/s.
Is gluster 10 times slower than NFS?
Something is going on there. On my gigabit setups I see 100-120 MB / sec
writes for pure distribute and about 45-55 MB / sec with replica 2. What
block size are you using? I could see that if you were writing something
like 4k or under but 64k and up you should be getting about what I said.
Can you tell me more about your test?
Block size is 50M:
root@gladsheim:/# mount -t glusterfs node2:/test ~/mnt
root@gladsheim:/# dd if=/dev/zero of=~/mnt/testfile.null bs=50M count=10
10+0 records in
10+0 records out
524288000 bytes (524 MB) copied, 46.6079 s, 11.2 MB/s
root@gladsheim:/# dd if=~/mnt/testfile.null of=/dev/null bs=50M count=10
10+0 records in
10+0 records out
524288000 bytes (524 MB) copied, 45.7487 s, 11.5 MB/s
It doesn't depend on whether I use node1 or node2 for the mount.
Here is how I usually run:
[root@gqac022 gluster-mount]# time `dd if=/dev/zero of=/gluster-mount/test.txt
bs=1024k count=1000; sync`
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 9.12639 s, 115 MB/s
real 0m9.205s
user 0m0.000s
sys 0m0.670s
[root@gqac022 gluster-mount]# sync; echo 3 > /proc/sys/vm/drop_caches
[root@gqac022 gluster-mount]# dd if=./test.txt of=/dev/null bs=1024k count=1000
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 9.04464 s, 116 MB/s
And with your commands:
[root@gqac022 gluster-mount]# dd if=/dev/zero of=/gluster-mount/testfile.null
bs=50M count=10
10+0 records in
10+0 records out
524288000 bytes (524 MB) copied, 5.00876 s, 105 MB/s
[root@gqac022 gluster-mount]# sync; echo 3 > /proc/sys/vm/drop_caches
[root@gqac022 gluster-mount]# dd if=./testfile.null of=/dev/null bs=1024k
count=1000
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 4.51992 s, 116 MB/s
Normally to troubleshoot these issues I break the storage stack into it's
individual pieces and test each one. Try running on the bricks outside gluster
and see what you are getting. What all tuning are you using? Is anything
nonstandard? What are the disks?
No tuning so far. Just peered and tried my luck.
node1 is LXC using LVM2 on RAID5 as brick. Here I see a raw performance:
root@muspelheim:~# time `dd if=/dev/zero
of=/srv/bricks/test1/data/test.txt bs=1024k count=1000; sync`
1000+0 Datensätze ein
1000+0 Datensätze aus
1048576000 Bytes (1,0 GB) kopiert, 0,313791 s, 3,3 GB/s
real 0m8.444s
user 0m0.004s
sys 0m0.452s
self-mount on the node yields:
root@muspelheim:~# time `dd if=/dev/zero of=~/mnt/test.txt bs=1024k
count=1000; sync`
1000+0 Datensätze ein
1000+0 Datensätze aus
1048576000 Bytes (1,0 GB) kopiert, 10,2122 s, 103 MB/s
real 0m15.492s
user 0m0.012s
sys 0m0.556s
which is the data rate to node2. node2 is a chroot on a SynologyNAS:
root@urdaborn:~# time `dd if=/dev/zero
of=/srv/bricks/test1/data/test2.txt bs=1024k count=1000; sync`
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 5.31103 s, 197 MB/s
real 0m5.693s
user 0m0.012s
sys 0m4.680s
root@urdaborn:~# time `dd if=/dev/zero of=./mnt/test2.txt bs=1024k
count=1000; sync`
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 15.172 s, 69.1 MB/s
real 0m15.765s
user 0m0.010s
sys 0m3.353s
so this already is only slightly more than half the network
bandwidth.The connection between the nodes is a dedicated GB ethernet,
so no disturbance by other services on the net.
Back on the test client (LXC on yet another physical machine):
root@gladsheim:/# time `dd if=/dev/zero of=~/mnt/testfile.null bs=1024k
count=1000; sync`
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 91.6532 s, 11.4 MB/s
real 1m34.534s
user 0m0.004s
sys 0m2.280s
All physical machines are attached to the same switch.
Regards,
- lars.
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