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https://issues.apache.org/jira/browse/HDDS-5850?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Bharat Viswanadham updated HDDS-5850:
-------------------------------------
Description:
When I am working on scm ratislog parser I see log segments are created with
very small files.
Then I remember this config, and some changes done in OM to improve perf when
it is set to 4MB.
With small files it has some performance affect, so we need similar change for
SCM.
was:
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*
> Update default value of 'ozone.scm.ha.ratis.segment.sizee' and
> 'preallocated.size' to improve SCM write perf
> ------------------------------------------------------------------------------------------------------------
>
> Key: HDDS-5850
> URL: https://issues.apache.org/jira/browse/HDDS-5850
> Project: Apache Ozone
> Issue Type: Bug
> Reporter: Rakesh Radhakrishnan
> Assignee: Rakesh Radhakrishnan
> Priority: Major
> Labels: om-perf, performance, pull-request-available
> Fix For: 1.0.0
>
>
> When I am working on scm ratislog parser I see log segments are created with
> very small files.
> Then I remember this config, and some changes done in OM to improve perf when
> it is set to 4MB.
> With small files it has some performance affect, so we need similar change
> for SCM.
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