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Posted to issues@ozone.apache.org by "Mukul Kumar Singh (Jira)" <ji...@apache.org> on 2020/07/04 17:47:00 UTC
[jira] [Resolved] (HDDS-3900) Update default value of
'ozone.om.ratis.segment.size' and 'preallocated.size' to improve OM write
perf
[ https://issues.apache.org/jira/browse/HDDS-3900?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Mukul Kumar Singh resolved HDDS-3900.
-------------------------------------
Fix Version/s: 0.6.0
Resolution: Fixed
> Update default value of 'ozone.om.ratis.segment.size' and 'preallocated.size' to improve OM write perf
> ------------------------------------------------------------------------------------------------------
>
> Key: HDDS-3900
> URL: https://issues.apache.org/jira/browse/HDDS-3900
> Project: Hadoop Distributed Data Store
> Issue Type: Bug
> Reporter: Rakesh Radhakrishnan
> Assignee: Rakesh Radhakrishnan
> Priority: Major
> Labels: om-perf, performance, pull-request-available
> Fix For: 0.6.0
>
>
> Based on the *OM* performance tests on HDDs - write heavy workload {{Synthetic NNLoadGenerator}} in single node HA, the default 16KB ratis segment size becomes the bottleneck which affects the OM performance.
> Below is the IOSTAT with 16KB segment.size and 16KB segment.preallocated.size, which causes high w_await time and very minimal batching <5 occurred in OM (most of the time during the run).
> {code:java}
> sdd: RATIS DISK
> Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
> sdd 0.00 0.00 0.00 138.00 0.00 1.27 18.88 21.99 65.25 0.00 65.25 6.88 94.90
> sdd 0.00 0.00 0.00 103.00 0.00 1.07 21.23 40.36 918.25 0.00 918.25 9.72 100.10
> sdd 0.00 0.00 0.00 104.00 0.00 1.04 20.55 30.08 1388.23 0.00 1388.23 9.62 100.10
> sdd 0.00 0.00 0.00 396.00 0.00 1.55 8.00 136.50 285.30 0.00 285.30 2.40 94.90
> {code}
>
> Below is the IOSTAT with 16MB segment.size and 16MB segment.preallocated.size. which minimizes the {{w_await}} time. This gives good performance improvement in traditional HDDs by doing more sync batching.
> {code:java}
> sdd: RATIS DISK
> Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
> sdd 0.00 0.00 0.00 125.74 0.00 19.85 323.34 3.05 24.28 0.00 24.28 7.17 90.10
> sdd 0.00 0.00 0.00 128.00 0.00 19.76 316.12 3.31 25.91 0.00 25.91 7.14 91.40
> sdd 0.00 0.00 0.00 115.00 0.00 4.59 81.81 0.93 8.10 0.00 8.10 8.04 92.50
> sdd 0.00 0.00 0.00 111.00 0.00 4.53 83.57 0.90 8.12 0.00 8.12 8.14 90.30
> sdd 0.00 0.00 0.00 115.00 0.00 4.64 82.64 0.93 8.08 0.00 8.08 8.10 93.20
> {code}
>
> Below is the IOSTAT with 4MB segment.size and 4MB segment.preallocated.size. which also minimizes the {{w_await}} time.
> {code:java}
> Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
> sdd 0.00 0.00 0.00 115.00 0.00 6.08 108.34 0.99 8.57 0.00 8.57 8.10 93.20
> sdd 0.00 0.00 0.00 122.00 0.00 7.81 131.13 1.48 12.15 0.00 12.15 7.80 95.10
> sdd 0.00 0.00 0.00 115.00 0.00 7.81 139.04 1.05 9.09 0.00 9.09 8.10 93.20
> sdd 0.00 0.00 0.00 115.00 0.00 7.85 139.78 1.04 8.95 0.00 8.95 8.03 92.30
> sdd 0.00 0.00 0.00 114.00 0.00 5.83 104.70 0.97 8.57 0.00 8.57 7.97 90.90
> sdd 0.00 0.00 0.00 115.00 0.00 7.80 138.92 1.05 9.10 0.00 9.10 8.11 93.30
> sdd 0.00 0.00 0.00 119.00 0.00 7.93 136.47 1.72 14.41 0.00 14.41 7.81 92.90
> {code}
>
> Recommended config could be a value in MBs, probably a value *higher than > 2MB or >4MB*
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