For some time now I’ve experience my mac to be very slow. Opening Vim would take minutes. Creating a new Tab in iTerm would take more than 20 seconds. What the hell is going on - this is a brand new MacBook Pro! ~ After investigating, using Activity Monitor I discovered the following:
- CPU’s idling at 3-5% usage
- +500M free RAM
- +200G free disk space
- Negligible amount of network traffic
- Very high amount of disk I/O writes (> 450w/s)
What’s causing disk I/O?#
So, something is using my disk. But what? The solution is to use the iotop utility:
sudo iotop -C 5 12
A common entry here is the mds procoess, which has an insane amount of BYTES. So, this mds process is causing a lot of I/O, causing things to get slow.
What’s the mds process do?#
A quick Google search reveals that the mds process is actually the Spotlight indexer service.
Disable Spotlight#
I don’t use Spotlight at all, so let’s disable it - preventing the disk I/O.
sudo mdutil -a -i off
That’s all. Spotlight indexing disabled. After a few seconds the disk I/O dropped from ± 450w/s to 0w/s. Vim starts ups again within a seconds. I’m happy.
Enabling Spotlight#
If, for some obscure reason, you want to re-enable Spotlight, use the following command:
sudo mdutil -a -i on