Hi Krist,
In my setup, if I mount the Gluster storage using NFS, I have an improvement of 3x in writes speed.I believe the answer for your questions is here:
In my case, as I run VMs and have shard enabled, changing the shard block size made a significant difference.
Does changing the number of Gluster threads make any difference in you setup as you have multiple clients accessing it simultaneously?
Best regards,
Everton Brogliatto
On Thu, Aug 24, 2017 at 9:01 PM, Krist van Besien <krist@xxxxxxxxxx> wrote:
We see this on the fuse client, but not when we use nfs. So the question I am interested in seeing an answer too is in what way is nfs different from fuse that could cause this.The problem we see is that after a certain time the fuse clients completely stop accepting writes. Something is preventing the application to write after a while.HiThis is gluster 3.8.4. Volume options are out of the box. Sharding is off (and I don't think enabling it would matter)I haven't done much performance tuning. For one thing, using a simple script that just creates files I can easily flood the network, so I don't expect a performance issue.My suspicion is it is locking related.KristOn 24 August 2017 at 14:36, Everton Brogliatto <brogliatto@xxxxxxxxx> wrote:Hi Krist,What are your volume options on that setup? Have you tried tuning it for the kind of workload and files size you have?I would definitely do some tests with feature.shard=on/off first. If shard is on, try playing with features.shard-block-size.Do you have jumbo frames (MTU=9000) enabled across the switch and nodes? if you have concurrent clients writing/reading, it could be beneficial to increase the number of client and server threads as well, try setting higher values for client.event-threads and server.event-threads.Best regards,Everton BrogliattoOn Thu, Aug 24, 2017 at 7:48 PM, Krist van Besien <krist@xxxxxxxxxx> wrote:______________________________KristAny suggestions?This video stream software is a bespoke solution, developped in house and it is thus possible to change the way it handles files so it works with the native client, but the programmers are looking at me for guidance.In what way do locking differ between the two different file systems, between NFS and Fuse, and how can the programmers work around any issues the fuse client might be causing?So if the problem is file locking, and the problem exists with the native client, and not using NFS, what could be the cause?We decided to test using the NFS client as well, and there the problem does not exist. But again, I (and the customer) would prefer not to use NFS, but use the native client in stead.However if we try the actualy workload we run in to trouble. Running the recorder software we can gradually ramp up the number of streams it records (and thus the number of files it creates), and at arou d 50 streams the recorder eventually stops writing files. According to the programmers that wrote it, it appears that it can no longer get the needed locks¸ and as a result just stops writing.I simulated that with a small script, that wrote 5M files and renamed them as fast as it could, and could easily create around 100 files/s (which abouts saturates the network). So I think the cluster is up to the task.- A gluster cluster of 3 nodes, with ample storage. They export several volumes.In this case the gluster system is used to store video streams. Basicaly the setup is the following:Hi all,I usualy advise clients to use the native client if at all possible, as it is very robust. But I am running in to problems here.- The network is 10GB, switched.- A "recording server" which subscribes to multi cast video streams, and records them to disk. The recorder writes the streams in 10s blocks, so when it is for example recording 50 streams it is creating 5 files a second, each about 5M. it uses a write-then-rename process.
--Vriendelijke Groet | Best Regards | Freundliche Grüße | CordialementKrist van Besien
senior architect, RHCE, RHCSA Open Stack
Red Hat Red Hat Switzerland S.A.
krist@xxxxxxxxxx M: +41-79-5936260
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--Vriendelijke Groet | Best Regards | Freundliche Grüße | CordialementKrist van Besien
senior architect, RHCE, RHCSA Open Stack
Red Hat Red Hat Switzerland S.A.
krist@xxxxxxxxxx M: +41-79-5936260
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