Avoiding common pitfallsEdit online Common problems and how to avoid them. Ensuring a 25 GB RoCE connection to a CISCO switch worksUsing a RoCE adapter with a 25-Gigabit Ethernet connection to a Cisco switch requires a special setting.Ensuring correct channel path statusEnsure that you varied the path offline before you perform a planned task on it.Determining channel path usage on LPARTo determine the usage of a specific channel path on LPAR, for example, to check whether traffic is distributed evenly over all channel paths, use the channel path measurement facility.Ignore unnecessary I/O devicesAn instance of Linux® on IBM® Z should ignore all I/O devices that it does not currently use.Using cio_ignoreWith cio_ignore, essential devices might be hidden. Excessive z/VM guest swappingAvoid excessive guest swapping by using the timed page pool size and the static page pool size attributes.Booting stops with disabled wait stateAn automatic processor type check might stop the boot process with a disabled wait PSW.LPAR auto-configuration overrides persistent configurationAfter upgrading Linux®, persistent device configurations that were specified with chzdev are overridden with the auto-configuration.Preparing for dump-on-panicSet up your system to automatically create a memory dump after a kernel panic.Function unavailable or degraded in Linux on z/VMFor some functions, Linux® on z/VM® issues diagnose instructions to the z/VM® hypervisor.Parent topic: Diagnostics and troubleshooting