Red Hat Bugzilla – Bug 1283410
cache mode must be the default mode for tiered volumes
Last modified: 2016-09-17 11:40:09 EDT
+++ This bug was initially created as a clone of Bug #1282076 +++
Description of problem:
Make cache mode the default for tiering
Version-Release number of selected component (if applicable):
Steps to Reproduce:
test mode is default
cache mode is default
test mode is for internal QE testing and should not be used by customers. Test mode forces all unused data to be destaged from the hot tier when no IO is received, rendering the SSD unused / wasted. If the demote cycle time is made large as a workaround, data will stay on the hot tier but will not react to changing conditions, which means unused data may fill the hot tier resource. A long cycle times also means the system will stay static even when close to full, which will put the system into a degraded mode.
The cache mode is supposed to keep data on the hot tier but also demote data quickly when the hot tier is close to full. The cycle time can be set to a desired reaction time to swap out lesser used data and bring in more frequently accessed data without flushing the entire SSD.
--- Additional comment from Vijay Bellur on 2015-11-14 14:57:34 EST ---
REVIEW: http://review.gluster.org/12581 (cluster/tier make cache mode default for tiered volumes) posted (#1) for review on master by Dan Lambright (firstname.lastname@example.org)
--- Additional comment from Vijay Bellur on 2015-11-17 07:18:33 EST ---
COMMIT: http://review.gluster.org/12581 committed in master by Dan Lambright (email@example.com)
Author: Dan Lambright <firstname.lastname@example.org>
Date: Sat Nov 14 14:35:26 2015 -0500
cluster/tier make cache mode default for tiered volumes
The default mode for tiered volumes must be cache. The current
test mode was for engineering and should ordinarily not be used
Signed-off-by: Dan Lambright <email@example.com>
Tested-by: Gluster Build System <firstname.lastname@example.org>
Reviewed-by: mohammed rafi kc <email@example.com>
With 3.7.5-7 build. Cache mode is the default now.
vol info shows as below:
[root@zod ~]# gluster v info metadata
Volume Name: metadata
Volume ID: 23dcc876-5343-4ab9-b320-844e30e4a67c
Number of Bricks: 16
Hot Tier :
Hot Tier Type : Distributed-Replicate
Number of Bricks: 2 x 2 = 4
Cold Tier Type : Distributed-Disperse
Number of Bricks: 2 x (4 + 2) = 12
Also, file promotes and demotes are happening(sanity check)only when the watermark criteria is hit.
changed the mode to test and test mode works as previous default behavior
Hence moving to verified
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.