Support Questions
Find answers, ask questions, and share your expertise
Announcements
Alert: Welcome to the Unified Cloudera Community. Former HCC members be sure to read and learn how to activate your account here.

Cloudera manager reporting incorrect metrics

Highlighted

Cloudera manager reporting incorrect metrics

Expert Contributor

Hi , 

 

Can someonet ell me what could be the issue where the cloudera manger reporting incorrect host metrics for example disk usage. 

 

This is what i get from the command line

 

desind@*******:~#> df -h /kafka/data/sd*
Filesystem Size Used Avail Use% Mounted on
/dev/xvdb 985G 4.0G 931G 1% /kafka/data/sda
/dev/xvdc 985G 72M 935G 1% /kafka/data/sdb
/dev/xvdd 985G 16G 920G 2% /kafka/data/sdc
/dev/xvde 985G 3.8G 931G 1% /kafka/data/sdd

 

 

Now from the GUI i see these metrics. Please find the attachment.Metrics for host from cloudera managerMetrics for host from cloudera manager

2 REPLIES 2

Re: Cloudera manager reporting incorrect metrics

Super Collaborator

The metrics looks right based on the screenshot 

 

desind@*******:~#> df -h /kafka/data/sd*
Filesystem Size Used Avail Use% Mounted on
/dev/xvdb 985G 4.0G 931G 1% /kafka/data/sda 
/dev/xvdc 985G 72M 935G 1% /kafka/data/sdb
/dev/xvdd 985G 16G 920G 2% /kafka/data/sdc
/dev/xvde 985G 3.8G 931G 1% /kafka/data/sdd

Taking /dev/xvdb as an example
sum(Size-Avail) = 54G [Used] - where df -h shows 4.0G [Used].
And CM correctly shows (± rounding) 53.8G/984.2G

 

Note, there's also 5% reserve for few Linux file system see [0].

With regards to  df -h the article in [1] elaborates "Why The Linux df Command Shows Lesser Free Disk Space?"

 

[0] "Reserving some number of filesystem blocks for use by privileged processes is done to avoid filesystem fragmentation, and to allow system daemons, such as syslogd(8), to continue to function correctly after non-privileged processes are prevented from writing to the filesystem. Normally, the default percentage of reserved blocks is 5%." from man tune2fs

[1] http://www.walkernews.net/2011/01/22/why-the-linux-df-command-shows-lesser-free-disk-space/

Highlighted

Re: Cloudera manager reporting incorrect metrics

Expert Contributor

The used for /dev/xvdb 4.0G is not the same shown from the CM UI. 

If i calucalte it is correct. 985G  -  931G = 54G

 

but the linux command line shows used 4G. i am wondering if linux file system is showing incorrectly. 

Don't have an account?
Coming from Hortonworks? Activate your account here