Bharat Viswanadham created HDDS-5850:
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Summary: 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
Fix For: 1.0.0
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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