Difference between df command and Bigsister output
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#226 Difference between df command and Bigsister output
Hi,
Last days, I found a problem regarding disk agent.
The problem is follows, if I do 'df' from commandline,
I get this:
# df -x iso9660 -x ufs -x nfs -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/cciss/c0d0p1 15573852 13364016 1418728 91% /
tmpfs 1037280 16 1037264 1% /dev/shm
/dev/cciss/c0d0p5 15573852 8025368 6757376 55% /os-b
/dev/cciss/c0d0p6 15573852 6779396 8003348 46% /os-c
/dev/cciss/c0d0p7 15573852 8179500 6603244 56% /os-d
/dev/cciss/c0d0p3 2068172 290996 1672116 15% /opt/local
/dev/sdd1 8657308 3013188 5644120 35% /u01
/dev/sde1 8657308 785372 7871936 10% /u02
/dev/sdf1 8795136 6147072 2648064 70% /u51
/dev/sdc2 8795136 3250176 5544960 37% /u52
, but if I read the output from BS, I see this:
/dev/cciss/c0d0p1 14.9GB 12.7GB 2.1GB 86% /
tmpfs 1013MB 16kB 1013MB 0% /dev/shm
/dev/cciss/c0d0p5 14.9GB 7.7GB 7.2GB 52% /os-b
/dev/cciss/c0d0p6 14.9GB 6.5GB 8.4GB 44% /os-c
/dev/cciss/c0d0p7 14.9GB 7.8GB 7.1GB 53% /os-d
/dev/cciss/c0d0p3 2GB 284.2MB 1.7GB 14% /opt/local
/dev/sdd1 8.3GB 2.9GB 5.4GB 35% /u01
/dev/sde1 8.3GB 767MB 7.5GB 9.1% /u02
/dev/sdf1 8.4GB 5.9GB 2.5GB 70% /u51
/dev/sdc2 8.4GB 3.1GB 5.3GB 37% /u52
Do you see the difference in the percentage usage? BS
monitores 86% and the commandline shows 91% for '/'
directory. I also found out, the bigger partition, the
greater difference between commandline and BS.
I had a look into your code and I saw, that you
calculate the value from partition size and the actual
usage of this partition. But 'df' does not give a
proper value for the usage. That's the reason for this
difference!
I also made some more investigations:
This is a platform intepended problem. On all UNIX
platform, I found the same discrepance.
cheers Daniel
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That's because df figures take reserved space into account, while Big Sister does not. So, df reports in its percentage figures, how much space is left for normal users, while Big Sister reports how much space is free on disk. I know, that's a trap for the unaware since Big Sister reports space that is existent, however only usable by superusers. An interesting side-effect of this is that some versions of df actually can report a disk more than 100% full :-))