LS, We have a GlusterFS cluster which consists of 4 nodes with one brick each and a distributed-replicated volume of 72 TB. Today I extended the cluster to 8 machines and added new bricks to the volume, so it now contains 8 bricks. I didn’t start the rebalance yet to limit the impact during the day but to my surprise all glusterfsd process went sky high and performance was really really bad. So effectively I cause downtime to our storage service while I didn’t anticipated this, hence I didn’t do any rebalance yet. Can somebody explain to me why adding bricks to a volume causes this high CPU usage? I can imagine the meta data needed to be synced but if this is so heavy, why can’t I tune this? This is my current volume setup: Volume Name: gv0 Type: Distributed-Replicate Volume ID: 0322f20f-e507-492b-91db-cb4c953a24eb Status: Started Number of Bricks: 4 x 2 = 8 Transport-type: tcp Bricks: Brick1: s-s35-06:/glusterfs/bricks/brick1/brick Brick2: s-s35-07:/glusterfs/bricks/brick1/brick Brick3: s-s35-08:/glusterfs/bricks/brick1/brick Brick4: s-s35-09:/glusterfs/bricks/brick1/brick Brick5: v39-app-01:/glusterfs/bricks/brick1/gv0 Brick6: v39-app-02:/glusterfs/bricks/brick1/gv0 Brick7: v39-app-03:/glusterfs/bricks/brick1/gv0 Brick8: v39-app-04:/glusterfs/bricks/brick1/gv0 Options Reconfigured: performance.cache-size: 256MB nfs.disable: on geo-replication.indexing: off geo-replication.ignore-pid-check: on changelog.changelog: on performance.io-thread-count: 32 performance.write-behind-window-size: 5MB Met vriendelijke groet / kind regards, Sander Zijlstra | Linux Engineer | SURFsara | Science Park 140 | 1098XG Amsterdam | T +31 (0)6 43 99 12 47 | sander.zijlstra@xxxxxxxxxxx | www.surfsara.nl |
Regular day off on friday |
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