Hi Ingard, On 24/04/17 14:43, Ingard Mevåg wrote:
I've done some more testing with tc and introduced latency on one of my testservers. With 9ms latency artificially introduced using tc ( sudo tc qdisc add dev bond0 root netem delay 9ms ) to a testserver in the same DC as the disperse volume servers I get more or less the same throughput as I do when testing DC1 <-> DC2 (which has ~9ms ping). I know distribute volumes were more sensitive to latency in the past. At least I can max out a 1gig link with 9-10ms latency when using distribute. Disperse seems to max at 12-14MB/s with 8-10ms latency.
A pure distributed volume is a simple configuration that simply forwards a request to one of the bricks. No additional overhead is needed.
However a dispersed 4+2 volume needs to talk simultaneously to 6 bricks, meaning 6 network round-trips for every request. Additionally it needs to keep integrity so one or more additional requests are needed.
If network latency is high, all these requests contribute to increase the overall request latency, limiting the throughput.
Have you tried a replica 2 or 3 ? it uses very similar integrity mechanisms so it'll also add some latency. Maybe not so much as a dispersed 4+2, but it should be perceptible.
Another test to confirm that the limitation is caused by latency is to do multiple writes in parallel. Each write will be limited by the latency, but the aggregated throughput should saturate the bandwidth, specially on a 1Gb ethernet.
Even better performance can be achieved if you distribute the writes to multiple clients or mount points (assuming they are not writing to the same file).
Xavi
ingard 2017-04-24 14:03 GMT+02:00 Ingard Mevåg <ingard@xxxxxxxx <mailto:ingard@xxxxxxxx>>: I can confirm mounting the disperse volume locally on one of the three servers i got 211 MB/s with dd if=/dev/zero of=./local.dd.test bs=1M count=10000. Its not very good concidering 10gig network, but at least 20x better than 10-12MB/s 2017-04-24 13:53 GMT+02:00 Pranith Kumar Karampuri <pkarampu@xxxxxxxxxx <mailto:pkarampu@xxxxxxxxxx>>: +Ashish Ashish, Could you help Ingard? Do let me know what you find. On Mon, Apr 24, 2017 at 4:50 PM, Ingard Mevåg <ingard@xxxxxxxx <mailto:ingard@xxxxxxxx>> wrote: Hi. I can't see a fuse thread at all. Please see attached screenshot of top process with threads. Keep in mind this is from inside the container. 2017-04-24 12:17 GMT+02:00 Pranith Kumar Karampuri <pkarampu@xxxxxxxxxx <mailto:pkarampu@xxxxxxxxxx>>: We were able to saturate hardware with EC as well. Could you check 'top' in threaded mode to see if fuse thread is saturated when you run dd? On Mon, Apr 24, 2017 at 3:27 PM, Ingard Mevåg <ingard@xxxxxxxx <mailto:ingard@xxxxxxxx>> wrote: Hi I've been playing with disperse volumes the past week, and so far i can not get more than 12MB/s when i do a write test. I've tried a distributed volume on the same bricks and gotten close to gigabit speeds. iperf confirms gigabit speeds to all three servers in the storage pool. The three storage servers have 10gig nics (connected to the same switch). The client is for a now a docker container in a 2nd DC (latency roughly 8-9 ms). dpkg -l|grep -i gluster ii glusterfs-client 3.10.1-ubuntu1~xenial1 amd64 clustered file-system (client package) ii glusterfs-common 3.10.1-ubuntu1~xenial1 amd64 GlusterFS common libraries and translator modules ii glusterfs-server 3.10.1-ubuntu1~xenial1 amd64 clustered file-system (server package) $ gluster volume info Volume Name: DFS-ARCHIVE-001 Type: Disperse Volume ID: 1497bc85-cb47-4123-8f91-a07f55c11dcc Status: Started Snapshot Count: 0 Number of Bricks: 1 x (4 + 2) = 6 Transport-type: tcp Bricks: Brick1: dna-001:/mnt/data01/brick Brick2: dna-001:/mnt/data02/brick Brick3: dna-002:/mnt/data01/brick Brick4: dna-002:/mnt/data02/brick Brick5: dna-003:/mnt/data01/brick Brick6: dna-003:/mnt/data02/brick Options Reconfigured: transport.address-family: inet nfs.disable: on Anyone know the reason for the slow speeds on disperse vs distribute? kind regards ingard _______________________________________________ Gluster-users mailing list Gluster-users@xxxxxxxxxxx <mailto:Gluster-users@xxxxxxxxxxx> http://lists.gluster.org/mailman/listinfo/gluster-users <http://lists.gluster.org/mailman/listinfo/gluster-users> -- Pranith -- Ingard Mevåg Driftssjef Jottacloud Mobil: +47 450 22 834 <tel:+47%20450%2022%20834> E-post: ingard@xxxxxxxxxxxxxx <mailto:ingard@xxxxxxxxxxxxxx> Webside: www.jottacloud.com <http://www.jottacloud.com> -- Pranith -- Ingard Mevåg Driftssjef Jottacloud Mobil: +47 450 22 834 <tel:+47%20450%2022%20834> E-post: ingard@xxxxxxxxxxxxxx <mailto:ingard@xxxxxxxxxxxxxx> Webside: www.jottacloud.com <http://www.jottacloud.com> -- Ingard Mevåg Driftssjef Jottacloud Mobil: +47 450 22 834 E-post: ingard@xxxxxxxxxxxxxx <mailto:ingard@xxxxxxxxxxxxxx> Webside: www.jottacloud.com <http://www.jottacloud.com> _______________________________________________ Gluster-users mailing list Gluster-users@xxxxxxxxxxx http://lists.gluster.org/mailman/listinfo/gluster-users
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