I have a Linux file server. I feel it is slow and want to improve the performance. Before I upgrade the hardware, i want to know what is exact bottleneck, CPU, Memory, Disk, or network?
I know there are vmstat, iostat, etc. But I feel it is not so helpful. For example, iostat shows how many block read/write per seconds, but I don't know how big the number is too big! For vmstat, it shows how many percent is idle. But 50% idle is buy or not busy? My version of vmstat cannot show the percentage CPU spending on waiting for IO.
Anyone can give some information about some good open source software to analysis CPU, memory, disk and network?