3 ms·

My computer (macOS Sierra, HFS (Journaled)) has 2x spinning drives of 3TB, and operations are noticeably quicker after an overnight defragmentation run, which I

My computer (macOS Sierra, HFS (Journaled)) has 2x spinning drives of 3TB, and operations are noticeably quicker after an overnight defragmentation run, which I do twice a year or so. Anecdata, granted - but it works for my situation.

pfranz 8y ago
If it works for you, then great, but here's an article from almost 10 years ago where Apple discourages defragging[1]. There's a bunch of other articles with more specifics showing that advanced defrag features from the 90s were built into the OS years ago[2]. [1] https://support.apple.com/en-us/HT1375 https://support.apple.com/en-us/HT1375 (last updated 2010) [2] http://osxbook.com/software/hfsdebug/fragmentation.html http://osxbook.com/software/hfsdebug/fragmentation.html (from 2004)
- petecooper 8y ago
  I just took a snapshot of one of my hard drives (2TB) from iDefrag: https://imgur.com/bdGcXXC https://imgur.com/bdGcXXC The red slivers towards the lower middle are where the reported fragmented files are located, and the lower right is the fragmented files listed by number of fragments descending. The anonymised .mkv files are training videos with multiple language and subtitle streams. They're exported to a scratch drive and then copied to the the drive they currently reside on. After a full, offline defrag (including a b-tree rebuild) the legend for defragmentation is a neatly arranged list of that blue/grey colour, no red to be seen.
sjwright 8y ago
Given that macOS automatically defragments sub-20MB files on the fly (which covers 99% of the files which affect perceived system performance) I'd wager money that your experience is 100% placebo. I know from personal experience how powerful this placebo effect can be.
- petecooper 8y ago
  >Given that macOS automatically defragments sub-20MB files on the fly (which covers 99% of the files which affect perceived system performance) I'd wager money that your experience is 100% placebo. Perhaps. I can certainly tell the difference performance when an overnight defrag run has finished, and I have no beef with you to prove or disprove a point. If you're ever in North Cornwall, UK: drop me a line and I'll show you a before and after over a mug of coffee/tea/etc.

pfranz 8y ago

If it works for you, then great, but here's an article from almost 10 years ago where Apple discourages defragging[1]. There's a bunch of other articles with more specifics showing that advanced defrag features from the 90s were built into the OS years ago[2]. [1] https://support.apple.com/en-us/HT1375 https://support.apple.com/en-us/HT1375 (last updated 2010) [2] http://osxbook.com/software/hfsdebug/fragmentation.html http://osxbook.com/software/hfsdebug/fragmentation.html (from 2004)

petecooper 8y ago
I just took a snapshot of one of my hard drives (2TB) from iDefrag: https://imgur.com/bdGcXXC https://imgur.com/bdGcXXC The red slivers towards the lower middle are where the reported fragmented files are located, and the lower right is the fragmented files listed by number of fragments descending. The anonymised .mkv files are training videos with multiple language and subtitle streams. They're exported to a scratch drive and then copied to the the drive they currently reside on. After a full, offline defrag (including a b-tree rebuild) the legend for defragmentation is a neatly arranged list of that blue/grey colour, no red to be seen.

sjwright 8y ago

Given that macOS automatically defragments sub-20MB files on the fly (which covers 99% of the files which affect perceived system performance) I'd wager money that your experience is 100% placebo. I know from personal experience how powerful this placebo effect can be.

petecooper 8y ago
>Given that macOS automatically defragments sub-20MB files on the fly (which covers 99% of the files which affect perceived system performance) I'd wager money that your experience is 100% placebo. Perhaps. I can certainly tell the difference performance when an overnight defrag run has finished, and I have no beef with you to prove or disprove a point. If you're ever in North Cornwall, UK: drop me a line and I'll show you a before and after over a mug of coffee/tea/etc.