SharePoint Logs

By default SharePoint maintains different Logs in SharePoint 14 hive
folder, where you can get lots of Information. The default location for
SharePoint Logs is C:\Program files\Common Files\Microsoft Shared\Web Server
Extensions\14\LOGS.

The LOGS folder contains log files (.log), data files (.txt), and usage
files (.usage). The file naming convention for a SharePoint trace log is the
server name followed by a date and time stamp.

Log files are text files. So we can open by using Text editor. We can get
more information by using correlation ID.

You can also use ULS Viewer Tool to read the Logs.

You can also use PowerShell to read logs by using below command:

Get-SPLogEvent

Change Logs Default Location:

If you want to change the default location to a different location then
follow below steps:

Open SharePoint Central Administration -> Monitoring, Then click on
Configure diagnostic logging.

Then click on Configure usage and health data collection and change the
default location. Also you can change Maximum Log File Size.