Linux configuration considerations
This topic describes about the Linux configuration that you need to consider while installing or configuring IBM Spectrum Scale™ on your cluster.
- Why can only one host successfully attach to the Fibre
Channel loop and see the Fibre Channel disks?
Your host bus adapter may be configured with an enabled Hard Loop ID that conflicts with other host bus adapters on the same Fibre Channel loop.
To see if that is the case, reboot your machine and enter the adapter bios with <Alt-Q> when the Fibre Channel adapter bios prompt appears. Under the Configuration Settings menu, select Host Adapter Settings and either ensure that the Adapter Hard Loop ID option is disabled or assign a unique Hard Loop ID per machine on the Fibre Channel loop.
- Could the GPFS daemon be terminated due to a memory
shortage?
The Linux virtual memory manager (VMM) exhibits undesirable behavior for low memory situations on nodes, where the processes with the largest memory usage are killed by the kernel (using OOM killer), yet no mechanism is available for prioritizing important processes that should not be initial candidates for the OOM killer. The GPFS™ mmfsd daemon uses a large amount of pinned memory in the pagepool for caching data and metadata, and so the mmfsd process is a likely candidate for termination if memory must be freed up.
- What are the performance tuning suggestions?
For an up-to-date list of tuning suggestions, see the IBM Spectrum Scale FAQ in IBM® Knowledge Center.
For Linux on z Systems™, see also the Device Drivers, Features, and Commands topic in the Linux on z Systems library overview.