Category: Unix/Linux Performance

How to get CORRECT memory usage for Linux

One of the most common mistakes made by Linux users, is to run free (Mem: line) or sar to get memory utilization.   The memory used fields include the space used by the OS to cache files and directory info cace,…

Increasing Linux Ring Buffer Size

This doesn’t work on all drivers, but on the bnx2x and other it does.   In particular, if you are seeing packet drops this can help.   Use ethtool –g <interface> to see the buffer settings. # ethtool -g eth0 Ring…

Identifing Linux disks

Identify scsi disk paths – Mapping Devices for disk in ‘/dev/sd*[a-z]’; do printf “%s %s\n” “$(basename $disk)” “$(scsi_id -p 0x83 -gs /block/$(basename $disk))” done