I am on MacOs 10.12.5. I am trying to do high volume I/O but some task managed by launchd hits every modified disk block every 30 seconds. When this happens my high volume I/O has to compete causing a severe slow down. How do I identify the problem task?
I believe it is something to do with launchd because
fs_usage -w -f diskio tells me it is. Every 30 seconds it outputs a list like this for every changed disk block in the system (apologies you have to scroll to see launchd):
14:34:33.887889 WrData[AT3] D=0x0068c05a B=0x1000 /dev/disk2 /Users/simon/Library/Application Support/Google/Chrome/Default/Session Storage/000430.log 0.000145 W launchd.9793620 14:34:33.887893 WrData[AT3] D=0x00549a2b B=0x1000 /dev/disk2 /Users/simon/Library/Application Support/Google/Chrome/Default/Session Storage/LOG 0.000107 W launchd.9793620 14:34:33.887895 WrData[AT3] D=0x00570119 B=0x1000 /dev/disk2 /Users/simon/Library/Saved Application State/com.apple.Terminal.savedState/window_2.data 0.000070 W launchd.9793620 14:34:33.887897 WrData[AT3] D=0x0056fab5 B=0x1000 /dev/disk2 /Users/simon/Library/Saved Application State/com.apple.Terminal.savedState/window_3.data 0.000064 W launchd.9793620 14:34:33.887912 WrData[ANT3] D=0x0056ffd0 B=0x1000 /dev/disk2 /Users/simon/Library/Saved Application State/com.apple.Terminal.savedState/windows.plist 0.000072 W launchd.9793620
I thought it might be my McAfee anti-virus software, so I excluded the files I was writing from real-time scanning, and then tried turning it off.
I then thought it might be Spotlight search, but again excluding the volume my data files are on did not prevent this launchd task from re-accessing the files.
launchctl list shows a list of 327 tasks. I would love to be able to narrow this down to just one.
Whilst I am sure the task runs every 30 seconds having watched it many times, I cannot find any mention of an appropriate "30" in the configuration files. I have:
- No mention of "30" in /System/Library/LaunchAgents
- One mention of "30" in /System/Library/LaunchDaemons
- com.apple.powerd.swd.plist sets ThrottleInterval to 30
- No mention of "30" in /Library/LaunchAgents
- One mention of "30" in /Library/LaunchDaemons
- com.mcafee.virusscan.fmpd.plist sets ExitTimeout to 30
- No mention of "30" in ~/Library/LaunchAgents
Although McAfee does mention "30", disabling it and excluding the files made no difference.
Any help in identifying the task which is accessing changed disk blocks would be appreciated.