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https://issues.apache.org/jira/browse/HDFS-16678?focusedWorklogId=796166&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-796166
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ASF GitHub Bot logged work on HDFS-16678:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 28/Jul/22 18:52
Start Date: 28/Jul/22 18:52
Worklog Time Spent: 10m
Work Description: goiri commented on code in PR #4606:
URL: https://github.com/apache/hadoop/pull/4606#discussion_r932570164
##########
hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/metrics/RBFMetrics.java:
##########
@@ -537,35 +547,34 @@ public int getNumEnteringMaintenanceDataNodes() {
@Override // NameNodeMXBean
public String getNodeUsage() {
- float median = 0;
- float max = 0;
- float min = 0;
- float dev = 0;
+ double median = 0;
+ double max = 0;
+ double min = 0;
+ double dev = 0;
final Map<String, Map<String, Object>> info = new HashMap<>();
try {
- RouterRpcServer rpcServer = this.router.getRpcServer();
- DatanodeInfo[] live = rpcServer.getDatanodeReport(
- DatanodeReportType.LIVE, false, timeOut);
+ DatanodeInfo[] live = null;
+ if (this.enableGetDNUsage) {
+ RouterRpcServer rpcServer = this.router.getRpcServer();
+ live = rpcServer.getDatanodeReport(DatanodeReportType.LIVE, false,
timeOut);
+ } else {
+ LOG.debug("Getting node usage is disabled.");
+ }
- if (live.length > 0) {
- float totalDfsUsed = 0;
- float[] usages = new float[live.length];
+ if (live != null && live.length > 0) {
+ double[] usages = new double[live.length];
int i = 0;
for (DatanodeInfo dn : live) {
usages[i++] = dn.getDfsUsedPercent();
- totalDfsUsed += dn.getDfsUsedPercent();
}
- totalDfsUsed /= live.length;
Arrays.sort(usages);
median = usages[usages.length / 2];
max = usages[usages.length - 1];
min = usages[0];
- for (i = 0; i < usages.length; i++) {
- dev += (usages[i] - totalDfsUsed) * (usages[i] - totalDfsUsed);
- }
- dev = (float) Math.sqrt(dev / usages.length);
+ StandardDeviation deviation = new StandardDeviation();
+ dev = deviation.evaluate(usages);
}
} catch (IOException e) {
LOG.error("Cannot get the live nodes: {}", e.getMessage());
Review Comment:
> I feel it would be better this way.
>
> ```
> LOG.error("Cannot get the live nodes.", e).
> ```
Do we want to have the full stack trace? I think it is pretty clear what the
error is here without it.
Issue Time Tracking
-------------------
Worklog Id: (was: 796166)
Time Spent: 1h 50m (was: 1h 40m)
> RBF supports disable getNodeUsage() in RBFMetrics
> -------------------------------------------------
>
> Key: HDFS-16678
> URL: https://issues.apache.org/jira/browse/HDFS-16678
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: ZanderXu
> Assignee: ZanderXu
> Priority: Major
> Labels: pull-request-available
> Time Spent: 1h 50m
> Remaining Estimate: 0h
>
> In our prod environment, we try to collect RBF metrics every 15s through
> jmx_exporter. And we found that collection task often failed.
> After tracing and found that the collection task is blocked at getNodeUsage()
> in RBFMetrics, because it will collection all datanode's usage from
> downstream nameservices. This is a very expensive and almost useless
> operation. Because in most scenarios, each NameSerivce contains almost the
> same DNs. We can get the data usage's from any one nameservices, not from RBF.
> So I feel that RBF should supports disable getNodeUsage() in RBFMetrics.
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