I ran df -h several times in rapid succession, and I'm getting these results.  Can somebody help me understand why?I'm not sure how much back-story you need.  The disk in question is a Toshiba DT01ABA300 external USB hard drive which I am currently using for backups.  But I'm not adding and removing GB of files, I'm just running a backup which should primarily (if not only) be adding data to the disk.$ df -h /storageFilesystem            Size  Used Avail Use% Mounted on/dev/sdi1             2.7T  2.1T  517G  81% /storage  $ df -h /storageFilesystem            Size  Used Avail Use% Mounted on/dev/sdi1             2.7T  2.1T  466G  83% /storage  $ df -h /storageFilesystem            Size  Used Avail Use% Mounted on/dev/sdi1             2.7T  2.3T  261G  91% /storage  $ df -h /storageFilesystem            Size  Used Avail Use% Mounted on/dev/sdi1             2.7T  2.2T  363G  87% /storage  $ df -h /storageFilesystem            Size  Used Avail Use% Mounted on/dev/sdi1             2.7T  2.1T  517G  81% /storage  $ df -h /storageFilesystem            Size  Used Avail Use% Mounted on/dev/sdi1             2.7T  2.3T  312G  89% /storage  $ df -h /storageFilesystem            Size  Used Avail Use% Mounted on/dev/sdi1             2.7T  2.1T  466G  83% /storage
df fluctuates badly
disk usage;usb drive;external hdd