Non-traditional disks


I have a machine with the following:

[email protected]:~$ df -h
Filesystem            Size  Used Avail Use% Mounted on
                       60G   37G   20G  65% /
none                  5.7G  392K  5.7G   1% /dev
none                  5.7G  7.3M  5.7G   1% /dev/shm
none                  2.0G   38M  2.0G   2% /tmp
none                  5.7G  292K  5.7G   1% /var/run
none                  5.7G  4.0K  5.7G   1% /var/lock
none                  5.7G     0  5.7G   0% /lib/init/rw
none                   60G   37G   20G  65% /var/lib/ureadahead/debugfs
                      168G  125G   34G  79% /home
                      237G   45G  181G  20% /opt
                      168G  125G   34G  79% /home/rtucker
/dev/sdh1              15G  2.3G   13G  16% /media/RST7983

[email protected]:~$ mount
/dev/mapper/witte-root on / type ext4 (rw,relatime,errors=remount-ro,discard)
proc on /proc type proc (rw,noexec,nosuid,nodev)
none on /sys type sysfs (rw,noexec,nosuid,nodev)
none on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)
none on /sys/kernel/security type securityfs (rw)
none on /dev type devtmpfs (rw,mode=0755)
none on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)
none on /dev/shm type tmpfs (rw,nosuid,nodev)
none on /tmp type tmpfs (rw,nosuid,nodev,size=2G,nr_inodes=200k,mode=01777)
none on /var/run type tmpfs (rw,nosuid,mode=0755)
none on /var/lock type tmpfs (rw,noexec,nosuid,nodev)
none on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
none on /var/lib/ureadahead/debugfs type debugfs (rw,relatime)
/dev/mapper/witte-home on /home type ext4 (rw,relatime,errors=remount-ro,discard)
/dev/mapper/witte-opt on /opt type ext4 (rw,relatime,errors=remount-ro,discard)
nfsd on /proc/fs/nfsd type nfsd (rw)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev)
/home/rtucker/.Private on /home/rtucker type ecryptfs (ecryptfs_check_dev_ruid,ecryptfs_sig=65709baf18e8fc35,ecryptfs_fnek_sig=e570c30060c25877,ecryptfs_cipher=aes,ecryptfs_key_bytes=16,ecryptfs_unlink_sigs)
gvfs-fuse-daemon on /home/rtucker/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=rtucker)
/dev/sdh1 on /media/RST7983 type vfat (rw,nosuid,nodev,uhelper=udisks,uid=10001,gid=10001,shortname=mixed,dmask=0077,utf8=1,flush)

[email protected]:~$ sudo lvs
  LV                    VG    Attr   LSize   Origin Snap%  Move Log Copy%  Convert
  home                  witte -wi-ao 170.00g                                      
  opt                   witte -wi-ao 240.00g                                      
  root                  witte -wi-ao  60.00g                                      
  swap                  witte -wi-ao  12.00g                                      
  vmdk-demo-linuxmint13 witte -wi-a-  30.00g                                      
  vmdk-demo-windows8    witte -wi-a-  55.00g                                      
  vmdk-gandalf          witte -wi-a- 200.00g                                      
  vmdk-windows7         witte -wi-ao  55.00g                                      
  vmdk-winxp            witte -wi-a-  15.00g                                      

This here machine is a walking edge case :-)

Longview finds /dev/mapper/witte-root, witte-opt, and witte-home and notes them as "Device mapper". Alas, it does not attempt to display disk capacity / inode usage data, despite them being locally-mounted ext* filesystems.

It also falsely detects /dev/mapper as being mounted on "/opt", and textually indicates current space/inode utilization (correct for /opt), but none of the graphs work.

This machine, BTW, has two physical mirrored spinny-disks appearing as /dev/md0, along with a SSD, all of which are managed via LVM. Staff may be able to find the machine at:

It does the right thing with my flash drive, though, and displays I/O (I didn't want to know how bad it was…) and space utilization. Nice. I wonder what'll happen when I unmount it…….

4 Replies

This is great. We spent some time working with edge cases like yours and I could have sworn I got them all. I'll definitely be asking some more questions soon!

Sorry about your flash drive :P

I intentionally set up my weirdest systems first. :-) Let me know if there's any info I can provide. I can also hook you up with ssh access if you want to taste the rainbow first-hand. It's a very special machine…

I can't wait – I should be able to come back to this pretty soon. I'll shoot you a PM when we're ready, and maybe we can keep this thread going with any fun public details as we go. Thanks a ton for the rainbow offer! I can't tell you how many times I've asked for the contents of a disk-related file.

Btw, tmpfs are missing too. I suppose that's on purpose given their transient nature? But what if they're listed in fstab, perhaps the client could include them then?


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