Does every mount on FreeBSD need the 10% "root space"?

Question

So, our servers are being managed by a hosting provider. These servers are running FreeBSD. Each disk we let them mount loses 10% of it's disk space.

I know (if I understand correctly) that this is normal and the reason is that the file-system allocates 10% diskspace for the root user. I read for example this: https://forums.freebsd.org/threads/29336/

Now I do understand that the operating systems needs space here and there to do stuff. However: when we mount a disk under - let's say - /data/web/my-user/some-sub-directory-somewhere-for-a-specific-goal/

Does that mount need to lose that 10% diskspace? Or can/should the hosting provider the tunefs -m option in order to save us some money.

Any FreeBSD guru's who can recommend something on this matter?

Answer 1

Basically that reserved space of 5% (default on Linux) or 10% (on BSD) is used to prevent file system fragmentantion which translates into poor performance when the disk partition or disk drive is used over 95%. I am usually using tune2fs -m 1 /dev/partition in order to change the default reserved % to 1% reservation.

If you do know that you are going to use no more than 95% from that disk/partition then you can change the default reserved space to a lower value without an actual impact on the filesysytem's performance

I think this provides a pretty good answer to your question: https://unix.stackexchange.com/questions/7950/reserved-space-for-root-on-a-filesystem-why

It's not related to BSD but to unix/linux but the things are pretty much the same.