I've the following entry in log:
24/08/2015 18:00:32.197 com.apple.mtmd[55]: attempting to thin because of low free space on Macintosh HD (/) by removing 2015-08-24 16:57:54 +0100, estimate 0 bytes to recover, 1 snapshot can be thinned
But I've over 25GB free:
$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/disk0s2 466G 442G 24G 95% /
In top
:
Load Avg: 2.39, 3.67, 3.70 CPU usage: 8.71% user, 6.5% sys, 85.22% idle SharedLibs: 9592K resident, 9392K data, 0B linkedit. MemRegions: 223410 total, 6136M resident, 53M private, 798M shared. PhysMem: 11G used (5491M wired), 272M unused.
VM: 1131G vsize, 1066M framework vsize, 18083888(372) swapins, 21344621(0) swapouts. Networks: packets: 10086831/7650M in, 8482767/3357M out. Disks: 11688769/221G read, 9345680/217G written.
$ top -l 1 | head -n 10 | grep PhysMem
PhysMem: 11G used (5536M wired), 74M unused.
And vm_stat
:
$ vm_stat 1
Mach Virtual Memory Statistics: (page size of 4096 bytes)
free active specul inactive throttle wired prgable faults copy 0fill reactive purged file-backed anonymous cmprssed cmprssor dcomprs comprs pageins pageout swapins swapouts
48498 739133 2327 684917 0 1405393 17258 1682134K 20168887 2191469K 339740K 14307441 170267 1256110 6862590 1312575 192808K 223457K 172163K 1539229 18095123 21344621
48373 738368 2327 684917 0 1406527 17258 2018 226 627 0 0 170267 1255345 6862359 1312573 231 0 0 0 0 0
47801 739664 2333 684909 0 1405395 17268 1576 0 922 0 0 170273 1256633 6862196 1312573 163 0 1 0 0 0
I believe this state of a low free space breaks few apps (like Chrome) which behaves weird.
Why OS X is saying it is out of free space (low free space) on /
when it has a lot of it? Is it some kind of bug?
Best Answer
25GB is not alot of space on a nearly 500GB drive. It seems that OSX has a built-in alert for 5%.
Recall that the operating system needs to rely on the drive being available to manage conditions where there may not be enough memory to complete processes. This is what we call 'virtual memory'. OSX will swap older memory items to the hard drive if needed.
In addition, OSX wants enough space to provide the ability to write all of current memory to the hard drive in case of a power issue, so that you do not lose data due to battery issues. In this case, it needs at least enough space to ensure it can write 4GB/8GB/16GB depending on your RAM size.
All of these items are managed by the OS, and if it detects a condition where it may not be left with enough space on the hard drive to perform its functions, it will alert you the user.