First step, do a full and adequate backup. Accidents happen, and for all you know your XFS system might be slightly corrupt and might crash completely when resized. Or I could be a royal a*hole and being giving you bad advice just to imagine your face when the file system throws the bucket. Or, quite possibly, I could be convinced in good faith that these instructions will work, while they actually don't. I will be devastated when you tell me you lost all your precious data, but I won't be able to undo the damage.
The second step, you need to grow the partition. To do this, just resize the partition (you can even delete it and recreate it with the same start sector, provided of course you do not save and reboot until you've finished!).
There are also tools that will grow automatically the partition, and lots of tutorials. Here's one. But just search for "grow root partition without rebooting" and you should be good (yes, this is not your root partition but
/var - but this way you will select the "safer" tutorials. What works for / will work better with
Once you have done this (no need to reboot, yes, but you do need to reread the partition -
fdisk does this automatically, otherwise use
partprobe), you will have a partition like this (the actual end sector may vary slightly, "GB" size is something of a matter of taste)
Number Start (sector) End (sector) Size Code Name
1 2048 125824202 60.0 GiB 8300
but on this 60 GB partition, you will only still have 25 GB in the file system. You can safely reboot and use the system normally, you just won't have any extra space.
But before continuing: you did a full backup, did you?
At this point I might mention that you could also have done this differently by adding a new partition and leaving
/dev/sdc1 alone. For example, you have lots of data in
/home (say, 15 GB out of the old 25)? Create a
/dev/sdc2 with the extra 35 GB, move
/home there and you have now 15 GB free on
/dev/sdc1, 20 GB left on
/sdc2, and your original partition is left untouched (you still should have done a backup)! No need to resize anything, if the extra space on
/dev/sdc2 is enough for you.
But if it is not, and you want it all in a single chunk, okay, grow
/dev/sdc1 you must.
# xfs_growfs -n /dev/sdc1
will give you info about the existing 25GB filesystem. Data block count is probably around six million and a half.
Do this without the
-n option and - after a little while, which I usually spend whispering "at least I made a backup..." - you will see something like,
data blocks changed from 6553600 to 15728640
Just to be sure,
# xfs_info /dev/sdc1
should say among other things something like
data = bsize=4096 blocks=15728640, imaxpct=25
If you now run
df, it should display the new FS size of 60GB. Welcome to your larger disk!