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Posted to common-user@hadoop.apache.org by Erik Forsberg <fo...@opera.com> on 2010/01/14 09:43:08 UTC

"Lost" HDFS space

Hi!

I'm having trouble figuring out the numbers reported by 'hadoop dfs
-dus' versus the numbers reported by the namenode web interface.

I have a 4 node clusters, 4TB of disk on each node.

hadoop dfs -dus /
hdfs://hdp01-01:9000/	1691626356288

Numbers on datanode web interface:

Capacity	:	14.13 TB
DFS Remaining	:	1.41 TB
DFS Used	:	11.88 TB

My default replication level is 3, but the bulk of my files have their
replication level set to two. So looking at the 'dfs -dus' number, in
the worst case, I think I should be using 1691626356288*3=5074879068864
bytes, i.e. approx 5TB, not 11.88 as the web interface reports.

fsck seems happy:

Status: HEALTHY
 Total size:	1691626405661 B
 Total dirs:	11780
 Total files:	82137 (Files currently being written: 1)
 Total blocks (validated):	84054 (avg. block size 20125471 B)
 Minimally replicated blocks:	84054 (100.0 %)
 Over-replicated blocks:	6 (0.007138268 %)
 Under-replicated blocks:	1 (0.0011897114 %)
 Mis-replicated blocks:		0 (0.0 %)
 Default replication factor:	3
 Average block replication:	2.731268
 Corrupt blocks:		0
 Missing replicas:		6 (0.0026135363 %)
 Number of data-nodes:		4
 Number of racks:		1

This is on 0.18.3/Cloudera. 

I've also verified that the bulk on the data on my disks are under the
hadoop/dfs/data/current directory on each disk.

Clearly I'm misunderstanding something, or there's something weird
going on. Hints?

Thanks,
\EF
-- 
Erik Forsberg <fo...@opera.com>
Developer, Opera Software - http://www.opera.com/

Re: "Lost" HDFS space (SOLVED)

Posted by Erik Forsberg <fo...@opera.com>.
On Thu, 14 Jan 2010 01:11:29 -0800
Eli Collins <el...@cloudera.com> wrote:

> Are there a lot of files in the tmp directories in dfs.data.dir on
> each data node? What does du (on the host) for these directories
> report? This might be HDFS-821.  dfsadmin -report output would be
> useful as well.

Hmm.. seems I was a bit quick in drawing conclusions - I deleted a lot
of files before running the 'dfs -dus' commands, and it seems it takes
a while for the raw disk space to be reclaimed. My cluster is now at
6.72TB remaining (compared to 1.41 TB 10 minutes ago), and that figure
seems to be increasing as I write my mail. 

No, there are not much in the tmp directories. 

Thanks for replying anyway, I did learn something from the
experience :-).

Thanks,
\EF
-- 
Erik Forsberg <fo...@opera.com>
Developer, Opera Software - http://www.opera.com/

Re: "Lost" HDFS space

Posted by Eli Collins <el...@cloudera.com>.
On Thu, Jan 14, 2010 at 12:43 AM, Erik Forsberg <fo...@opera.com> wrote:
> Hi!
>
> I'm having trouble figuring out the numbers reported by 'hadoop dfs
> -dus' versus the numbers reported by the namenode web interface.
>
> I have a 4 node clusters, 4TB of disk on each node.
>
> hadoop dfs -dus /
> hdfs://hdp01-01:9000/   1691626356288
>
> Numbers on datanode web interface:
>
> Capacity        :       14.13 TB
> DFS Remaining   :       1.41 TB
> DFS Used        :       11.88 TB
>
> My default replication level is 3, but the bulk of my files have their
> replication level set to two. So looking at the 'dfs -dus' number, in
> the worst case, I think I should be using 1691626356288*3=5074879068864
> bytes, i.e. approx 5TB, not 11.88 as the web interface reports.
>
> fsck seems happy:
>
> Status: HEALTHY
>  Total size:    1691626405661 B
>  Total dirs:    11780
>  Total files:   82137 (Files currently being written: 1)
>  Total blocks (validated):      84054 (avg. block size 20125471 B)
>  Minimally replicated blocks:   84054 (100.0 %)
>  Over-replicated blocks:        6 (0.007138268 %)
>  Under-replicated blocks:       1 (0.0011897114 %)
>  Mis-replicated blocks:         0 (0.0 %)
>  Default replication factor:    3
>  Average block replication:     2.731268
>  Corrupt blocks:                0
>  Missing replicas:              6 (0.0026135363 %)
>  Number of data-nodes:          4
>  Number of racks:               1
>
> This is on 0.18.3/Cloudera.
>
> I've also verified that the bulk on the data on my disks are under the
> hadoop/dfs/data/current directory on each disk.
>
> Clearly I'm misunderstanding something, or there's something weird
> going on. Hints?

Hey Erik,

Are there a lot of files in the tmp directories in dfs.data.dir on
each data node? What does du (on the host) for these directories
report? This might be HDFS-821.  dfsadmin -report output would be
useful as well.

Thanks,
Eli