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https://issues.apache.org/jira/browse/HADOOP-3187?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12600664#action_12600664
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Konstantin Shvachko commented on HADOOP-3187:
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# DFSAdmin.printHelp()
-- summary should be consistent with the detailed usage messages
<code>
"\t[-refreshNodes] [-setQuota <dirname> <N>] [-clrQuota <dirname>]\n" +
</code>
-- the same in printUsage()
-- The documentation for setQuota defines parameters in the reverse order
-setQuota N name.
# I am not sure, but my first thought was that QuotaExceededException is a
partial case of AccessControlException.
One way to treat it is: if quota is exceeded for a directory then the write
access to the directory is forbidden.
# File QuotaExceededException.java is missing in the patch.
# FSNamesystem.clearQuota() should not be public.
# Please use **-comments for new methods (private or not) so that they appear
in JavaDoc.
# unprotectedRenameTo() catches IOException which is never thrown.
# INodeDirectory.replaceChildWithSameName(newNode, oldNode) probably does not
need 2 parameters.
You can just use newNode and search for the old inode using the new one's name.
You do a binary search anyway. And the method name (ChildWithSameName) reflects
the semantics.
# INodeDirectoryWithQuota.count is int. This in fact imposes a restriction on
the number of files in hdfs compared to current implementation.
The restriction is imposed by making rootDir a INodeDirectoryWithQuota. The
quota is not set for the root by default,
but the count is an integer.
Right now our name-node cannot support Integer.MAX_VALUE number of files, but
may be in the future it will.
I think it is ok to have int count for directories that have their quotas set,
and I think it is all right to restrict
the quota values (and therefore the count) by Integer.MAX_VALUE. But regular
directories and especially the root
should be able to have more entries.
# The same with ContentSummary. fileCount and directoryCount fields should
remain long imo, while quota can be int.
# This is not introduced by your patch but could you please remove redundant
imports of java.io.DataInput and DataOutput
# When creating files and directories you first increment counters for all
directories with quotas then actually create
a new directory entry at the specified path. You restore the counters for the
directories only if one of the quotas
on the path happens to exceed the high mark. If something happens before file
or directory is actually
added but after the counters are incremented the quotas will be wrong. I think
it would be safer to
-# verify that no quotas are exceeded
-# add new directory entry
-# increment counters for directories with quotas on the path.
This will require splitting the updateCount() into 2 methods: one will verify
quotas and and the other will increment the counters.
> Quotas for name space management
> --------------------------------
>
> Key: HADOOP-3187
> URL: https://issues.apache.org/jira/browse/HADOOP-3187
> Project: Hadoop Core
> Issue Type: New Feature
> Reporter: Robert Chansler
> Assignee: Hairong Kuang
> Attachments: quota.patch, QuotasDesign.pdf, QuotasDesign1.pdf
>
>
> Create a quota mechanism for name space management.
> Quota set at a directory by super user restricts that number of names in and
> below that directory.
> Quota tested by create() and rename().
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