Besides the RAM there is a so called Swap, which is a virtual memory, where RAM content (pages) could be swapped-in in case there is not enough RAM available anymore. This swap is located on the disc and since disc reads and writes are slower than reading from RAM, accessing memory pages there will result […]
Archives for October 2015
Solaris : How to create processor set (pset) and associate it with a pool
Resource pools provide a mechanism for partitioning a system into persistent processor sets with optional scheduling class assignments. Pools even work with Dynamic Reconfiguration (DR). The post describes how to create a processor set and associate it with a pool. Before a processor pool can be created, the svc:/system/pools:default service must be enabled. It can […]
Solaris : How to set limit on the maximum number of open files per process
The maximum limit of open files per process can be limited by setting a hard limit and/or a soft limit. The hard limit can be set by the system administrator and be decreased by any user, whereas the soft limit can be set by any user, up to the hard limit. This document describes the […]
Solaris : How to find number of open files by a process
Sometimes, the error message “too many open files” is displayed in /var/adm/messages. In these cases, it is often useful to know how many files are currently open by a process. The number of files currently opened by a certain process can be examined by: 1. The pfiles command 2. Using the /proc file system Using […]
CentOS / RHEL : How to collect sosreport
The “sosreport” is a tool to collect troubleshooting data on RHEL/CentOS systems. It generates a compressed tarball of debugging information that gives an overview of the most important logs and configuration of a Linux system, to be sent to Redhat Support. Among other things, the sosreport includes information about the installed rpm versions, syslog, network […]
CentOS / RHEL 7 : How to Reset root password
Resetting root password in CentOS/RHEL 7 is slightly different than the older versions. The post describes the procedure to reset the lost root password. Reboot and edit grub2 Reboot the system and press any key to stop the auto-boot from the default kernel. Press “e” after selecting the kernel line. Append rd.break to kernel When […]
How to troubleshoot Solaris 10 SMF (Service Management Facility) related issues
Service management facility was first introduced in Solaris 10 for managing system and application services. This replaces the legacy init scripts and other startup scripts. The post discusses few basic troubleshooting techniques to resolve the SMF (Service Management Facility) related issues. Logfiles, Manifests and Methods 1. SMF logfiles can be found in the following locations: […]
Troubleshooting solaris 10 boot issues related to SMF and milestones
The post describes few troubleshooting tips for resolving the boot issues related to SMF(Service Management Facility). We can boot to early milestones and can go from one level to the next. this way we can identify the milestone causing the issues and eventually the service causing it. General troubleshooting Before going into more detailed troubleshooting, […]
How to install a ZFS boot block in solaris
The post discusses about how to install ZFS boot block on a system running a ZFS root filesystem. This is normally required when a system fails to boot from a disk containing a root filesystem. A typical error may include: The file just loaded does not appear to be executable Bootblk: can’t find the boot […]
lsof : Most commonly used examples
The lsof command lists open files, sockets, and pipes. You can use lsof command to see what files are held open (such as libraries or log files) and what ports daemons listen to. You can search for open files using lsof command. lsof should be run as the superuser (root) to see all open files. […]