Restrict Windows CBS.log verbosity, set log level, stop hectomegabyte info madness
On Windows 7 (Home Premium 64 Bit), hundreds of megabytes of logging that nobody will ever care to read are written to C:\Windows\Logs\CBS\CBS.log. Take a look, we're counting the lines here:
$ dir C:\Windows\Logs\CBS\CBS.log
03.10.2015 16:21 726.097.704 CBS.log
$ findstr /b 2015- C:\Windows\Logs\CBS\CBS.log | find /c ", Info"
2990118
$ findstr /b 2015- C:\Windows\Logs\CBS\CBS.log | find /c /v ", Info"
102
In straight words, the CBS logfile (CBS is short for Component Based Services, alias Trusted Installer, see Understanding Component-Based Servicing, Apr 2008, Microsoft Technet) at the moment takes up 700 MB, 200 of which written in the last 30 minutes, with the first entry stemming from 9 days ago.
Altogether that's close to 3 million entries, and almost the entirety of it at loglevel Info. Mind you, this is a human-readable log file format, apparently not for machine processing. Don't know about you, but the notion that I should bother to take account of 3 million lines of Info by default strikes me as bordering on the absurd.
I want this to stop because the disk and CPU activity serves no purpose other than needlessly slowing the system down.
So: How do I set the log level to Warning or Error? Where is this documented?
Plus: Imagine that instead of wading through hundreds of megs of Info (for little more than a week) you'd only keep the ~100 Error lines? Wouldn't that just make sense and actually provide clues in troubleshooting? You'd then still have the option to turn on Info in case a non-obvious installation problem arises.
Update:
Reading the comments, it seems I didn't word my question with sufficient clarity. I am not asking how to filter the humungous log file using command line utilities - because I already know how to do that. I am also not asking how to deal with the log files in the way of log rotation - because Windows will do that on its own when the file reaches some unknown threshold (although you'll find people asking why the file reaches 20 gigs). What I am asking is simply how to stop this crazy hectomegabyte logging from occurring in the first place, probably by setting the log level to something higher than Info. I just can't find the documentation on how to set the log level, possibly because it doesn't exist publicly. But there must be a way because any decent software provides a way to set the log level.
Update 2:
See the answer given. The registry setting seems to take effect and shut the log up, completely. Which is okay and a much better default than the current one. In order to make the registry edit, you need to fix permissions - see appendix.
Appendix: Permissions on Component Based Servicing registry key
When you try to set EnableLog to 0, you'll probably notice that you don't have write access to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing and stuff below it. You need to go "Edit » Permissions" in regedit and then take ownership before being allowed to make edits:
As a partial answer here's the setting to stop logging altogether: in the registry, navigate to
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Component Based Servicing]
and set EnableLog 0. Source: https://technet.microsoft.com/en-us/library/cc732334%28v=ws.10%29.aspx#CBS
CBS log is also filled by cleanmgr with roughly 150-200Mb of data even while cleaning almost 'nothing', thus filling op your disk in stead of cleaning.
I found CBS log can be cleared after stopping the TrustedInstaller service, restarting the Windows Module Installer afterwards will start the service again. Bear in mind the log is used by Microsoft in some debugging programs.