On Sunday, July 13, 2003, at 11:09 AM, Albert Strasheim wrote:
Secondly, Ganglia seems to think that there is 113.830 GB of disk
installed
in the machines, instead of ~80GB. df -a output is as follows.
[EMAIL PROTECTED] albert]$ df -a
Filesystem 1k-blocks Used Available Use% Mounted on
/dev/hda3 36298348 4655088 29799400 14% /
none 0 0 0 - /proc
/dev/hda1 101089 9067 86803 10% /boot
none 0 0 0 - /dev/pts
/dev/hdb1 38464340 70012 36440424 1% /home
none 514748 0 514748 0% /dev/shm
This is a known problem. I wrote the disk_total metric and I'm afraid
it is not accurate in all situations, as you have found.
The "disk_total" logic is as follows.
1. Read and parse /proc/mounts
2. Run statvfs() to find total blocks per filesystem. Sum them
together, multiply by block size.
Skip device names we have seen before (necessary so as not to count
automounted devices more than once - especially user's home
directories).
3. That's it. There is no other smarts about "special" filesystems such
as root and shmem.
I will work on making the disk metrics more accurate, however more
information from users would help very much. Does anyone else see
erroneous disk_total figures?
-fds
Jason Smith first found this problem. Here is his March 3, 2003 post:
--------
...
gmond's value is a lot
closer to what I add up with df, but still a little bit off and I am not
sure why. I noticed that the device_space function skips filesystems
that it has seen before, but it seems to go by the device name, not the
mount point. On my desktop (RedHat 2.4.18-24.7.x kernel), I seem to
have the root filesystem listed twice with different device names:
rootfs / rootfs rw 0 0
/dev/root / ext3 rw 0 0
Is this being counted twice?
~Jason
PS. Should devices with name equal to none also be skipped, like the
Linux kernel's shared memory fs? From /proc/mounts I have:
none /dev/shm tmpfs rw 0 0
And this filesystem does report some space that might be getting added
up with all the rest:
none 256816 0 256816 0% /dev/shm
----
Federico
Rocks Cluster Group, San Diego Supercomputing Center, CA
