I have a CentOS server with 4 disks, each with 1TB that totals to 3.636 TB of usable space (according to http://www.jonathanlaliberte.com/2007/12/18/calculating-actual-hard-disk-space/).
But the server df command shows the following status:
Filesystem Size Used Avail Use% Mounted on
/dev/md1 5.5G 3.0G 2.3G 57% /
/dev/md3 2.7T 2.7T 55G 99% /media
/dev/md0 181M 12M 160M 7% /boot
The swap is:
Swap: 5721 12 5708
So on overall, I'm about 900 GB short.
Any idea where that space went, and how I can get it back?
Thanks!
Best Answer
How are the MD devices configured? If you use a RAID1 (mirroring) or Raid5 (striped with parity), you will loose capacity. A RAID1 will have half the capacity of all disks, and a RAID5 will have the capacity of n-1 disks.