I think it might help if I had a better understanding of what I’m looking at:
/dev/mapper/centos-home 2.7T 33M 2.7T 1% /home
So /dev/mapper/centos-home is the file system and /home is where it is mounted.
I’m not sure I even know what that means. Are you saying that /hdfs/data even
though it’s in root that it’s still somehow pointing to /home? So confused.
It’s the part amount mounting a drive to another folder..on the same disk. Is
it kind of like how on Windows you can have more than one “drive” on a disk?
Adaryl "Bob" Wakefield, MBA
Principal
Mass Street Analytics, LLC
913.938.6685
www.linkedin.com/in/bobwakefieldmba
Twitter: @BobLovesData
From: Naganarasimha G R (Naga)
Sent: Thursday, November 05, 2015 7:50 PM
To: [email protected]
Subject: RE: hadoop not using whole disk for HDFS
Hi Bob,
1. I wasn’t able to set the config to /home/hdfs/data. I got an error that told
me I’m not allowed to set that config to the /home directory. So I made it
/hdfs/data.
Naga : I am not sure about the HDP Distro but if you make it point to
/hdfs/data, still it will be pointing to the root mount itself i.e.
/dev/mapper/centos-root 50G 12G 39G 23% /
Other Alternative is to mount the drive to some other folder other than /home
and then try.
2. When I restarted, the space available increased by a whopping 100GB.
Naga : I am particularly not sure how this happened may be you can again
recheck if you enter the command "df -h <path of the NM data dir configured>"
you will find out how much disk space is available on the related mount for
which the path is configured.
Regards,
+ Naga
--------------------------------------------------------------------------------
From: Adaryl "Bob" Wakefield, MBA [[email protected]]
Sent: Friday, November 06, 2015 06:54
To: [email protected]
Subject: Re: hadoop not using whole disk for HDFS
Is there a maximum amount of disk space that HDFS will use? Is 100GB that max?
When we’re supposed to be dealing with “big data” why is the amount of data to
be held on any one box such a small number when you’ve got terabytes available?
Adaryl "Bob" Wakefield, MBA
Principal
Mass Street Analytics, LLC
913.938.6685
www.linkedin.com/in/bobwakefieldmba
Twitter: @BobLovesData
From: Adaryl "Bob" Wakefield, MBA
Sent: Wednesday, November 04, 2015 4:38 PM
To: [email protected]
Subject: Re: hadoop not using whole disk for HDFS
This is an experimental cluster and there isn’t anything I can’t lose. I ran
into some issues. I’m running the Hortonworks distro and am managing things
through Ambari.
1. I wasn’t able to set the config to /home/hdfs/data. I got an error that told
me I’m not allowed to set that config to the /home directory. So I made it
/hdfs/data.
2. When I restarted, the space available increased by a whopping 100GB.
Adaryl "Bob" Wakefield, MBA
Principal
Mass Street Analytics, LLC
913.938.6685
www.linkedin.com/in/bobwakefieldmba
Twitter: @BobLovesData
From: Naganarasimha G R (Naga)
Sent: Wednesday, November 04, 2015 4:26 PM
To: [email protected]
Subject: RE: hadoop not using whole disk for HDFS
Better would be to stop the daemons and copy the data from /hadoop/hdfs/data to
/home/hdfs/data , reconfigure dfs.datanode.data.dir to /home/hdfs/data and then
start the daemons. If the data is comparitively less !
Ensure you have the backup if have any critical data !
Regards,
+ Naga
--------------------------------------------------------------------------------
From: Adaryl "Bob" Wakefield, MBA [[email protected]]
Sent: Thursday, November 05, 2015 03:40
To: [email protected]
Subject: Re: hadoop not using whole disk for HDFS
So like I can just create a new folder in the home directory like:
home/hdfs/data
and then set dfs.datanode.data.dir to:
/hadoop/hdfs/data,home/hdfs/data
Restart the node and that should do it correct?
Adaryl "Bob" Wakefield, MBA
Principal
Mass Street Analytics, LLC
913.938.6685
www.linkedin.com/in/bobwakefieldmba
Twitter: @BobLovesData
From: Naganarasimha G R (Naga)
Sent: Wednesday, November 04, 2015 3:59 PM
To: [email protected]
Subject: RE: hadoop not using whole disk for HDFS
Hi Bob,
Seems like you have configured to disk dir to be other than an folder in /home,
if so try creating another folder and add to "dfs.datanode.data.dir" seperated
by comma instead of trying to reset the default.
And its also advised not to use the root partition "/" to be configured for
HDFS data dir, if the Dir usage hits the maximum then OS might fail to function
properly.
Regards,
+ Naga
--------------------------------------------------------------------------------
From: P lva [[email protected]]
Sent: Thursday, November 05, 2015 03:11
To: [email protected]
Subject: Re: hadoop not using whole disk for HDFS
What does your dfs.datanode.data.dir point to ?
On Wed, Nov 4, 2015 at 4:14 PM, Adaryl "Bob" Wakefield, MBA
<[email protected]> wrote:
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 50G 12G 39G 23% /
devtmpfs 16G 0 16G 0% /dev
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 16G 1.4G 15G 9% /run
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/sda2 494M 123M 372M 25% /boot
/dev/mapper/centos-home 2.7T 33M 2.7T 1% /home
That’s from one datanode. The second one is nearly identical. I discovered
that 50GB is actually a default. That seems really weird. Disk space is cheap.
Why would you not just use most of the disk and why is it so hard to reset the
default?
Adaryl "Bob" Wakefield, MBA
Principal
Mass Street Analytics, LLC
913.938.6685
www.linkedin.com/in/bobwakefieldmba
Twitter: @BobLovesData
From: Chris Nauroth
Sent: Wednesday, November 04, 2015 12:16 PM
To: [email protected]
Subject: Re: hadoop not using whole disk for HDFS
How are those drives partitioned? Is it possible that the directories
pointed to by the dfs.datanode.data.dir property in hdfs-site.xml reside on
partitions that are sized to only 100 GB? Running commands like df would be a
good way to check this at the OS level, independently of Hadoop.
--Chris Nauroth
From: MBA <[email protected]>
Reply-To: "[email protected]" <[email protected]>
Date: Tuesday, November 3, 2015 at 11:16 AM
To: "[email protected]" <[email protected]>
Subject: Re: hadoop not using whole disk for HDFS
Yeah. It has the current value of 1073741824 which is like 1.07 gig.
B.
From: Chris Nauroth
Sent: Tuesday, November 03, 2015 11:57 AM
To: [email protected]
Subject: Re: hadoop not using whole disk for HDFS
Hi Bob,
Does the hdfs-site.xml configuration file contain the property
dfs.datanode.du.reserved? If this is defined, then the DataNode intentionally
will not use this space for storage of replicas.
<property>
<name>dfs.datanode.du.reserved</name>
<value>0</value>
<description>Reserved space in bytes per volume. Always leave this much
space free for non dfs use.
</description>
</property>
--Chris Nauroth
From: MBA <[email protected]>
Reply-To: "[email protected]" <[email protected]>
Date: Tuesday, November 3, 2015 at 10:51 AM
To: "[email protected]" <[email protected]>
Subject: hadoop not using whole disk for HDFS
I’ve got the Hortonworks distro running on a three node cluster. For some
reason the disk available for HDFS is MUCH less than the total disk space. Both
of my data nodes have 3TB hard drives. Only 100GB of that is being used for
HDFS. Is it possible that I have a setting wrong somewhere?
B.
