[
https://issues.apache.org/jira/browse/HDFS-12725?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16225679#comment-16225679
]
Wei-Chiu Chuang edited comment on HDFS-12725 at 10/30/17 9:23 PM:
------------------------------------------------------------------
Hi [~xiaochen] thanks for filing the jira and posting a patch.
It might make the code more readable if you can refactor the catch block into a
separate method, since that catch block is pretty long.
A little nit in the debug message:
{code}
LOG.debug("Best effort placement failed.");
{code}
It might also be useful to log numResultsOflastChoose and totalReplicaExpected.
One question regarding the test code:
{code}
for (int i = 0; i <= numSingleDnRacks; i++) {
racks[i] = "/rack" + i;
}
for (int i = numSingleDnRacks + 1; i < numDatanodes; i++) {
racks[i] = "/rack" + (numSingleDnRacks + (i % (
numRacks - numSingleDnRacks)));
}
{code}
Can you explain why the first loop is between 0 <= i <= numSingleDnRacks? Why
isn't it between 0 <= i <numSingleDnRacks?
was (Author: jojochuang):
Hi [~xiaochen] thanks for filing the jira and posting a patch.
A little nit in the debug message:
{code}
LOG.debug("Best effort placement failed.");
{code}
It might also be useful to log numResultsOflastChoose and totalReplicaExpected.
One question regarding the test code:
{code}
for (int i = 0; i <= numSingleDnRacks; i++) {
racks[i] = "/rack" + i;
}
for (int i = numSingleDnRacks + 1; i < numDatanodes; i++) {
racks[i] = "/rack" + (numSingleDnRacks + (i % (
numRacks - numSingleDnRacks)));
}
{code}
Can you explain why the first loop is between 0 <= i <= numSingleDnRacks? Why
isn't it between 0 <= i <numSingleDnRacks?
> BlockPlacementPolicyRackFaultTolerant still fails with racks with very few
> nodes
> --------------------------------------------------------------------------------
>
> Key: HDFS-12725
> URL: https://issues.apache.org/jira/browse/HDFS-12725
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: erasure-coding
> Affects Versions: 3.0.0
> Reporter: Xiao Chen
> Assignee: Xiao Chen
> Labels: hdfs-ec-3.0-must-do
> Attachments: HDFS-12725.01.patch, HDFS-12725.02.patch
>
>
> HDFS-12567 tries to fix the scenario where EC blocks may not be allocated in
> extremely rack-imbalanced cluster.
> The added fall-back step of the fix could be improved to do a best-effort
> placement. This is more likely to happen in testing than in real clusters.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
