Systems Administration Problem Solvers

Month: November 2012

  • Reset TopSpin Infiniband Switch Password

    To reset the password on a TopSpin Inifiband switch you’ll need to boot the system in the single user mode. To do this: Connect a console to the serial port and stop the booting at ppcboot.   Do the following: 1) at the “Hit any key to stop autoboot:” prompt, press a key quickly ( <5sec […]

  • CentOS / RHEL horrible disk performance with SSD

    noop, is essentially a first-in first-out (FIFO) queue with no extra logic. Each virtual machine can stop worrying about the disk, instead passing I/O requests along to the hypervisor to make a better decision about overall performance. Add “elevator=noop” to the kernel parameters in your boot loader’s configuration in /etc/grub.conf `echo noop > /sys/block/${DEVICE}/queue/scheduler`. Set […]