Awhile ago, when I first set up my unRAID server, the recommendation was to keep 5% of each disk as free space, with some users experiencing severe performance degradation if disk free space dropped too low.

 

For the old 250gb disks, and the like, this made some sense.  With new hard drive capacities as high as they are, is this still a valid rule?  For a 4TB hard drive, that would be leaving 200gb on the disk sitting there doing nothing - surely you don't need this much to prevent file fragmentation?

 

How much space you you leave on a disk before its time to get a new disk?  5GB? 20?

 

I just realized I filled up my drives to have about 2.5gb free per drive...i haven't noticed any slowdowns, but this is probably too little.  Now that I have a couple upgraded disks added to the array, I'm thinking of increasing it to 5gb per disk free, or maybe 10.  5% seems like overkill though...

 

Thoughts?

I fill my drives until there's not enough room for another DVD on them.  With modern high capacity drives that's about 99.9% full.    UnRAID doesn't fill them, as I have it set for high-water ... but when a drive gets close to full I manually write to the disk to fill it up.

 

Note that when a drive gets very full, WRITES get slow (actually the writes themselves aren't slow; but it takes a good while for the write to start -- I presume while the ReiserFS drivers are deciding exactly where to position the data (or perhaps re-arranging other data ... I'm not sure which).    But there is NO impact on READS ... these are just as fast regardless of how full the disk is.

 

Good to know!  I think I'll stick with 5gb free per drive, rather than 5%, and try not to copy over any large single files for the last bit.

I leave 150 - 250 GB free on each.

 

But I have directories that I don't want to break up on them so I occasionally have to move them around when I go to add more to said directory.  That is why I started leaving 150-250GB free on each drive.  it gives me room to add files before I might remove others.

I thought it was a good idea to have 2 times the free space availble as the largest file on the drive.

That was for repairs of files by checking program.

 

I thought it was a good idea to have 2 times the free space availble as the largest file on the drive.

That was for repairs of files by checking program.

 

I don't know if Reiserfsck requires that or not.  I've never needed to do that.  All of my files have checksums, and I can easily check them with a single click ("Verify checksum") ... and if anything was corrupt, I'd simply delete it and copy a good copy from my backups.    But if you use a utility that requires a specified amount of free space, obviously you should consider that when you're filling the drives.