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https://issues.apache.org/jira/browse/HDFS-4990?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13770623#comment-13770623
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Junping Du commented on HDFS-4990:
----------------------------------
Thanks for excellent work, Nicholas! The patch looks good to me, but have some
minor comments.
{code}
- private boolean isGoodTarget(DatanodeDescriptor node,$
+ private boolean isGoodTarget(DatanodeStorageInfo storage,$
long blockSize, int maxTargetPerRack,$
boolean considerLoad,$
- List<DatanodeDescriptor> results,
$
- boolean avoidStaleNodes) {$
+ List<DatanodeStorageInfo> results,
$
+ boolean avoidStaleNodes,$
+ StorageType storageType) {$
+ if (storage.getStorageType() != storageType) {$
+ logNodeIsNotChosen(storage,$
+ "storage types do not match, where storageType=" + storageType);$
+ return false;$
+ }$
+ DatanodeDescriptor node = storage.getDatanodeDescriptor();$
// check if the node is (being) decommissed$
if (node.isDecommissionInProgress() || node.isDecommissioned()) {$
- logNodeIsNotChosen(node, "the node is (being) decommissioned ");$
+ logNodeIsNotChosen(storage, "the node is (being) decommissioned ");$
return false;$
}$
$
if (avoidStaleNodes) {$
if (node.isStale(this.staleInterval)) {$
- logNodeIsNotChosen(node, "the node is stale ");$
+ logNodeIsNotChosen(storage, "the node is stale ");$
return false;$
}$
}$
$
{code}
the log info "storage types do not match, where storageType=" + storageType" is
a little confusing, may be "where storageType should be " + storageType could
be better? Also, do we think to check storage.getState() == NORMAL or !=
READ_ONLY?
There is some code style issues within this code block (not caused by your
patch), i.e. unnecessary spaces after "results," and a typo of decommissed, see
if you want to fix there.
> Block placement for storage types
> ---------------------------------
>
> Key: HDFS-4990
> URL: https://issues.apache.org/jira/browse/HDFS-4990
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: namenode
> Reporter: Suresh Srinivas
> Assignee: Tsz Wo (Nicholas), SZE
> Attachments: h4990_20130909.patch, h4990_20130916.patch,
> h4990_20130917b.patch, h4990_20130917c.patch, h4990_20130917.patch,
> h4990_20130918.patch
>
>
> Currently block location for writes are made based on:
> # Datanode load (number of transceivers)
> # Space left on datanode
> # Topology
> With storage abstraction, namenode must choose a storage instead of a
> datanode for block placement. It also needs to consider storage type, load on
> the storage etc.
> As an additional benefit, currently HDFS support heterogeneous nodes (nodes
> with different number of spindles etc.) poorly. This work should help solve
> that issue as well.
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