Should I ever run a Defrag operation if I only every insert/append to NAS (with no Snapshots enabled

---

StephenB wrote:

---

rn_enthusiast wrote:

For me, it is the same as with balance. I run it only if I need to but then again, I would know if/when I need to.

---

Part of the puzzle here is that with BTRFS there is a big difference between free space and unallocated space.  BTRFS needs enough unallocated space in order to work correctly.  If it runs totally out of unallocated space, a balance might not be able to fix it.  

 

Unfortunately, the admin UI doesn't report the amount of unallocated space - so you either need to monitor it with SSH commands, or you need to use free space as a rough proxy for unallocated space.  And that is rough - what started this discussion was a volume that had ~700 GiB of free space, but no unallocated space.

 

I think for almost all users here, the best approach is to be generous on the amount of free space you have, and run periodic balances to make sure the system maintains enough unallocated space. Most posters don't have the linux skills and BTRFS knowledge needed to assess the health of the file system with ssh (and resolve any issues), and many of the rest simply aren't going to monitor the file system that closely (until something goes wrong). 

 

 

 

 

---

I totally agree with everything you said. It is a good thing that the NAS allows you to "maintain" the filesystem without having to acquire deeper knowledge around it. I have a little self-made script that will pull filesystem stats every couple of weeks and dump that into a file. Admittedly, I look at the file probably every 3 months cause mostly I just forget about it :) But then again, if an issue does arise I am likely able to fix it anyway. For others it seems more reasonable with a "proactive" approach, indeed.