how full to fill a drive?

[pyrater]

90% 95? 98? 

 

10 GB = 20GB 300 GB??

[SSD]

At a minimum, leave room for one file as large as the largest file on the disk.

[John_M]

9 hours ago, SSD said:

At a minimum, leave room for one file as large as the largest file on the disk.

 

That's how I have Minimum Free Space configured in Share Settings.

 

However, I use the Fill-up allocation method and like to fill disks that seldom if ever have files changed as full as possible by copying files manually. It's safe to do so if full disks are essentially considered to be read-only and if you take care to ensure that you only copy from disk to disk and avoid falling foul of the user share copy bug. I used to fill them almost to the brim (< 100 MB remaining) but as time has passed and newer versions of XFS have come along I've had this cause error messages in the syslog. It seems that newer versions of XFS occupy more space with an empty file system and the error messages were XFS complaining that it was unable to expand/convert/modify the file system due to lack of space. An empty XFS file system on a 5 TB disk currently occupies 5.50 GB and on a 6 TB disk it occupies 6.60 GB (I see a pattern there! 0.11%) and that's considerably more than the few hundred MB it used to occupy in the early days of unRAID 6.0. So rather than fill my disks right to the brim I leave a little space (I aim for around 10 GB) to allow for future changes to XFS.

[trurl]

And even if you do fill disks manually, it is still a good idea to set Minimum Free for any user share to be larger than the largest file you will ever write. If you are copying, moving, etc directly to a disk that you want to fill, Minimum Free won't matter anyway, but it will at least keep user shares from deciding to write to a disk that is already mostly full.

[John_M]

Agreed. My Minimum Free is set to 50 GB, which is more than enough to cover the largest files I regularly deal with. I do handle larger files on occasion but they are special cases (system images, rather than media files) and are always written to a different user share that consists of just one disk with plenty of space left on it.

[Frank1940]

The only caveat is with disks that use the resierfs file system.  It has real write performance issues as the disks fill up and I suspect it has even bigger issues with disk capacities larger than about 3TB.  That is one of the reasons that it strongly recommended that users actually change the formatting on existing reiserfs data disks to XFS even though this is real pain in the you-know-what to do.