I am fighting this issue: Bug 1540376 – Tiered volume performance degrades badly after a volume stop/start or system restart. https://bugzilla.redhat.com/show_bug.cgi?id=1540376 Does anyone have any ideas on what might be causing this, and what a fix or work-around might be? Thanks! ~ Jeff Byers ~ Tiered volume performance degrades badly after a volume stop/start or system restart. The degradation is very significant, making the performance of an SSD hot tiered volume a fraction of what it was with the HDD before tiering. Stopping and starting the tiered volume causes the problem to exhibit. Stopping and starting the Gluster services also does. Nothing in the tier is being promoted or demoted, the volume starts empty, a file is written, then read, then deleted. The file(s) only ever exist on the hot tier. This affects GlusterFS FUSE mounts, and also NFSv3 NFS mounts. The problem has been reproduced in two test lab environments. The issue was first seen using GlusterFS 3.7.18, and retested with the same result using GlusterFS 3.12.3. I'm using the default tiering settings, no adjustments. Nothing of any significance appears to be being reported in the GlusterFS logs. Summary: Before SSD tiering, HDD performance on a FUSE mount was 130.87 MB/sec writes, 128.53 MB/sec reads. After SSD tiering, performance on a FUSE mount was 199.99 MB/sec writes, 257.28 MB/sec reads. After GlusterFS volume stop/start, SSD tiering performance on FUSE mount was 35.81 MB/sec writes, 37.33 MB/sec reads. A very significant reduction in performance. Detaching and reattaching the SSD tier restores the good tiered performance. ~ Jeff Byers ~ _______________________________________________ Gluster-users mailing list Gluster-users@xxxxxxxxxxx http://lists.gluster.org/mailman/listinfo/gluster-users
