Current mechanism for driving promotion/demotion is too rigorous. Fils are demoted automatically and the hot tier will be underutilized. Need a more flexible system that can be tuned according to customers needs according to various parameters. Need to gracefully handle situations where the hot tier becomes full.
REVIEW: http://review.gluster.org/12039 (cluster/tier: WIP add watermarks and policy driver) posted (#1) for review on master by Dan Lambright (dlambrig)
REVIEW: http://review.gluster.org/12039 (cluster/tier: WIP add watermarks and policy driver) posted (#2) for review on master by Dan Lambright (dlambrig)
REVIEW: http://review.gluster.org/12039 (cluster/tier: WIP add watermarks and policy driver) posted (#3) for review on master by Dan Lambright (dlambrig)
REVIEW: http://review.gluster.org/12039 (cluster/tier: WIP add watermarks and policy driver) posted (#4) for review on master by Dan Lambright (dlambrig)
REVIEW: http://review.gluster.org/12039 (cluster/tier: WIP add watermarks and policy driver) posted (#5) for review on master by Dan Lambright (dlambrig)
REVIEW: http://review.gluster.org/12039 (cluster/tier: add watermarks and policy driver) posted (#6) for review on master by Dan Lambright (dlambrig)
REVIEW: http://review.gluster.org/12039 (cluster/tier: add watermarks and policy driver) posted (#7) for review on master by Dan Lambright (dlambrig)
REVIEW: http://review.gluster.org/12039 (cluster/tier: add watermarks and policy driver) posted (#8) for review on master by Dan Lambright (dlambrig)
REVIEW: http://review.gluster.org/12039 (cluster/tier: add watermarks and policy driver) posted (#24) for review on master by Dan Lambright (dlambrig)
COMMIT: http://review.gluster.org/12039 committed in master by Dan Lambright (dlambrig) ------ commit 672baab88fb7f32e844cd4be22e0924e4e0e83fc Author: Dan Lambright <dlambrig> Date: Fri Sep 18 00:49:06 2015 -0400 cluster/tier: add watermarks and policy driver This fix introduces infrastructure to support different policies for promotion and demotion. Currently the tier feature automatically promotes and demotes files periodically based on access. This is good for testing but too stringent for most real workloads. It makes it difficult to fully utilize a hot tier- data will be demoted before it is touched- its unlikely a 100GB hot SSD will have all its data touched in a window of time. A new parameter "mode" allows the user to pick promotion/demotion polcies. The "test mode" will be used for *.t and other general testing. This is the current mechanism. The "cache mode" introduces watermarks. The watermarks represent levels of data residing on the hot tier. "cache mode" policy: The % the hot tier is full is called P. Do not promote or demote more than D MB or F files. A random number [0-100] is called R. Rules for migration: if (P < watermark_low) don't demote, always promote. if (P >= watermark_low) && (P < watermark_hi) demote if R < P; promote if R > P. if (P > watermark_hi) always demote, don't promote. gluster volume set {vol} cluster.watermark-hi % gluster volume set {vol} cluster.watermark-low % gluster volume set {vol} cluster.tier-max-mb {D} gluster volume set {vol} cluster.tier-max-files {F} gluster volume set {vol} cluster.tier-mode {test|cache} Change-Id: I157f19667ec95aa1d53406041c1e3b073be127c2 BUG: 1257911 Signed-off-by: Dan Lambright <dlambrig> Reviewed-on: http://review.gluster.org/12039 Tested-by: Gluster Build System <jenkins.com> Reviewed-by: Atin Mukherjee <amukherj>
This bug is getting closed because a release has been made available that should address the reported issue. In case the problem is still not fixed with glusterfs-3.8.0, please open a new bug report. glusterfs-3.8.0 has been announced on the Gluster mailinglists [1], packages for several distributions should become available in the near future. Keep an eye on the Gluster Users mailinglist [2] and the update infrastructure for your distribution. [1] http://blog.gluster.org/2016/06/glusterfs-3-8-released/ [2] http://thread.gmane.org/gmane.comp.file-systems.gluster.user