Bug 1426606

Summary: dht/rebalance: Increase maximum read block size from 128 KB to 1 MB
Product: [Community] GlusterFS Reporter: Vijay Bellur <vbellur>
Component: coreAssignee: bugs <bugs>
Status: CLOSED CURRENTRELEASE QA Contact:
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Priority: medium    
Version: mainlineCC: atumball, bugs
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Fixed In Version: glusterfs-6.x Doc Type: If docs needed, set a value
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Last Closed: 2019-05-11 10:17:17 UTC Type: ---
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Description Vijay Bellur 2017-02-24 12:43:35 UTC
commit 17cce29c4da1d086aaaba852971b76fe4488b360
Author: Shreyas Siravara <sshreyas>
Date:   Thu Aug 4 11:44:53 2016 -0700

    dht/rebalance: Increase maximum read block size from 128 KB to 1 MB
    
    Summary:
    - The maximum block size, `DHT_REBALANCE_BLKSIZE`, is set to 128 KB.
    - As a result, migrating files in the megabytes to gigabytes can take much longer than necessary.
    - Some preliminary results by bumping the blocksize:
    
    With 128 KB:
      [2016-08-04 11:40:19.251167] I [MSGID: 109028] [dht-rebalance.c:2196:gf_defrag_status_get] 0-glusterfs: Rebalance is completed. Time taken is 15.00 secs
      [2016-08-04 11:40:19.251189] I [MSGID: 109028] [dht-rebalance.c:2200:gf_defrag_status_get] 0-glusterfs: Files migrated: 49, size: 2569011200, lookups: 149, failures: 0, skipped: 0
    
    With 1 MB:
      [2016-08-04 11:41:21.093662] I [MSGID: 109028] [dht-rebalance.c:2196:gf_defrag_status_get] 0-glusterfs: Rebalance is completed. Time taken is 7.00 secs
      [2016-08-04 11:41:21.093687] I [MSGID: 109028] [dht-rebalance.c:2200:gf_defrag_status_get] 0-glusterfs: Files migrated: 49, size: 2569011200, lookups: 149, failures: 0, skipped: 0
    
    - This is a cherry-pick of D3670927 to 3.8.
    
    Test Plan: Tested rebalance on devserver.
    
    Reviewed By: dph, rwareing
    
    Change-Id: Ide2edbf87ef9ae2b32a03f189c57b63e2f233fc8
    Signed-off-by: Shreyas Siravara <sshreyas>
    Reviewed-on: http://review.gluster.org/16078
    CentOS-regression: Gluster Build System <jenkins.org>
    NetBSD-regression: NetBSD Build System <jenkins.org>
    Smoke: Gluster Build System <jenkins.org>
    Reviewed-by: Kevin Vigor <kvigor>