<div dir="ltr">what is the per thread CPU usage like on these clients? With highly concurrent workloads we've seen single thread that reads requests from /dev/fuse (fuse reader thread) becoming bottleneck. Would like to know what is the cpu usage of this thread looks like (you can use top -H).<br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Mar 4, 2019 at 3:39 PM Hu Bert <<a href="mailto:revirii@googlemail.com">revirii@googlemail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Good morning,<br>
<br>
we use gluster v5.3 (replicate with 3 servers, 2 volumes, raid10 as<br>
brick) with at the moment 10 clients; 3 of them do heavy I/O<br>
operations (apache tomcats, read+write of (small) images). These 3<br>
clients have a quite high I/O wait (stats from yesterday) as can be<br>
seen here:<br>
<br>
client: <a href="https://abload.de/img/client1-cpu-dayulkza.png" rel="noreferrer" target="_blank">https://abload.de/img/client1-cpu-dayulkza.png</a><br>
server: <a href="https://abload.de/img/server1-cpu-dayayjdq.png" rel="noreferrer" target="_blank">https://abload.de/img/server1-cpu-dayayjdq.png</a><br>
<br>
The iowait in the graphics differ a lot. I checked netstat for the<br>
different clients; the other clients have 8 open connections:<br>
<a href="https://pastebin.com/bSN5fXwc" rel="noreferrer" target="_blank">https://pastebin.com/bSN5fXwc</a><br>
<br>
4 for each server and each volume. The 3 clients with the heavy I/O<br>
have (at the moment) according to netstat 170, 139 and 153<br>
connections. An example for one client can be found here:<br>
<a href="https://pastebin.com/2zfWXASZ" rel="noreferrer" target="_blank">https://pastebin.com/2zfWXASZ</a><br>
<br>
gluster volume info: <a href="https://pastebin.com/13LXPhmd" rel="noreferrer" target="_blank">https://pastebin.com/13LXPhmd</a><br>
gluster volume status: <a href="https://pastebin.com/cYFnWjUJ" rel="noreferrer" target="_blank">https://pastebin.com/cYFnWjUJ</a><br>
<br>
I just was wondering if the iowait is based on the clients and their<br>
workflow: requesting a lot of files (up to hundreds per second),<br>
opening a lot of connections and the servers aren't able to answer<br>
properly. Maybe something can be tuned here?<br>
<br>
Especially the server|client.event-threads (both set to 4) and<br>
performance.(high|normal|low|least)-prio-threads (all at default value<br>
16) and performance.io-thread-count (32) options, maybe these aren't<br>
properly configured for up to 170 client connections.<br>
<br>
Both servers and clients have a Xeon CPU (6 cores, 12 threads), a 10<br>
GBit connection and 128G (servers) respectively 256G (clients) RAM.<br>
Enough power :-)<br>
<br>
<br>
Thx for reading && best regards,<br>
<br>
Hubert<br>
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</blockquote></div>