Good morning, we use gluster v5.3 (replicate with 3 servers, 2 volumes, raid10 as brick) with at the moment 10 clients; 3 of them do heavy I/O operations (apache tomcats, read+write of (small) images). These 3 clients have a quite high I/O wait (stats from yesterday) as can be seen here: client: https://abload.de/img/client1-cpu-dayulkza.png server: https://abload.de/img/server1-cpu-dayayjdq.png The iowait in the graphics differ a lot. I checked netstat for the different clients; the other clients have 8 open connections: https://pastebin.com/bSN5fXwc 4 for each server and each volume. The 3 clients with the heavy I/O have (at the moment) according to netstat 170, 139 and 153 connections. An example for one client can be found here: https://pastebin.com/2zfWXASZ gluster volume info: https://pastebin.com/13LXPhmd gluster volume status: https://pastebin.com/cYFnWjUJ I just was wondering if the iowait is based on the clients and their workflow: requesting a lot of files (up to hundreds per second), opening a lot of connections and the servers aren't able to answer properly. Maybe something can be tuned here? Especially the server|client.event-threads (both set to 4) and performance.(high|normal|low|least)-prio-threads (all at default value 16) and performance.io-thread-count (32) options, maybe these aren't properly configured for up to 170 client connections. Both servers and clients have a Xeon CPU (6 cores, 12 threads), a 10 GBit connection and 128G (servers) respectively 256G (clients) RAM. Enough power :-) Thx for reading && best regards, Hubert _______________________________________________ Gluster-users mailing list Gluster-users@xxxxxxxxxxx https://lists.gluster.org/mailman/listinfo/gluster-users
