Ugo's Blog

Here's a list of commands that you should execute and then share the output to someone who can help you figure out what resource is the bottleneck in your system. Note, it requires the  sysstat  and  procps  packages (ubuntu and RHEL and its derivatives): uptime vmstat 1 10 iostat -xN 2 10 mpstat -P ALL 3 10 pidstat 1 10 free -mw (or free -m, if your OS doesn't support -w)  uptime is to see the load averages on the system. vmstat is mostly used to tell if the system is swapping or not. If you see significant numbers in the 'si' and 'so' columns, your system is most likely swapping (using the hard drive as RAM), which usually slows performance a lot. iostat is mostly used to determine if your disk subsystem is not able to cope with the load. If you see one or more lines that shows 100 or close almost constantly, it is probably the case.  If it is your swap volume, you probably saw numbers in the 'si' and 'so' columns in the  vmsta...

Here's a list of commands that you should execute and then share the output to someone who can help you figure out what resource is the bottleneck in your system. Note, it requires the sysstat and  procps packages (ubuntu and RHEL and its derivatives): vmstat 1 10 iostat -xN 2 10 mpstat -P ALL 3 10 The first one is mostly used to tell if the system is swapping or not. If you see numbers in the 'si' and 'so' columns, your system is most likely swapping (using the hard drive as RAM), which usually slows performance a lot. The second one is mostly used to determine if your disk subsystem is not able to cope with the load. If you see one or more lines that shows 100 or close almost constantly, it is probably the case.  If it is your swap volume, you probably saw numbers in the 'si' and 'so' columns in the  vmstat  output. The third one shows the % of the CPU time used by different functions of the server. I'll explain the most used one...