http://www.cyberciti.biz/tips This is a Linux sys admin journal by Vivek about sys admin work, Linux tips & tricks, hacks, news and more. Fri, 03 Feb 2012 22:45:35 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 http://www.cyberciti.biz/tips/linux-core-dumps.html http://www.cyberciti.biz/tips/linux-core-dumps.html#comments Thu, 03 Jun 2010 09:34:03 +0000 Vivek Gite /dev/null 2>&1]]> http://www.cyberciti.biz/tips/?p=7006 Core dumps are often used to diagnose or debug errors in Linux or UNIX programs. Core dumps can serve as useful debugging aids for sys admins to find out why Application like Lighttpd, Apache, PHP-CGI or any other program crashed. Many vendors and open source project author requests a core file to troubleshoot a program. A core file is generated when an application program abnormally terminates due to bug, operating system security protection schema, or program simply try to write beyond the area of memory it has allocated, and so on. This article explains how to turn on core file support and track down bugs in programs.]]> http://www.cyberciti.biz/tips/linux-core-dumps.html/feed 18 http://www.cyberciti.biz/tips/linux-hugetlbfs-and-mysql-performance.html http://www.cyberciti.biz/tips/linux-hugetlbfs-and-mysql-performance.html#comments Wed, 20 May 2009 07:59:39 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=4773 Applications that perform a lot of memory accesses (several GBs) may obtain performance improvements by using large pages due to reduced Translation Lookaside Buffer (TLB) misses. HugeTLBfs is memory management feature offered in Linux kernel, which is valuable for applications that use a large virtual address space. It is especially useful for database applications such as MySQL, Oracle and others. Other server software(s) that uses the prefork or similar (e.g. Apache web server) model will also benefit.

The CPU's Translation Lookaside Buffer (TLB) is a small cache used for storing virtual-to-physical mapping information. By using the TLB, a translation can be performed without referencing the in-memory page table entry that maps the virtual address. However, to keep translations as fast as possible, the TLB is usually small. It is not uncommon for large memory applications to exceed the mapping capacity of the TLB. Users can use the huge page support in Linux kernel by either using the mmap system call or standard SYSv shared memory system calls (shmget, shmat). ]]> http://www.cyberciti.biz/tips/linux-hugetlbfs-and-mysql-performance.html/feed 10 http://www.cyberciti.biz/tips/sshd-server-optimization.html http://www.cyberciti.biz/tips/sshd-server-optimization.html#comments Wed, 14 May 2008 19:02:32 +0000 Vivek Gite http://www.cyberciti.biz/tips/?p=2295 http://www.cyberciti.biz/tips/sshd-server-optimization.html/feed 1 http://www.cyberciti.biz/tips/reboot-or-halt-linux-system-in-emergency.html http://www.cyberciti.biz/tips/reboot-or-halt-linux-system-in-emergency.html#comments Thu, 25 Aug 2005 23:53:00 +0000 LinuxTitli http://www.cyberciti.biz/tips/reboot-or-halt-linux-system-in-emergency.html http://www.cyberciti.biz/tips/reboot-or-halt-linux-system-in-emergency.html/feed 5 http://www.cyberciti.biz/tips/linux-as-router-for-dsl-t1-line-etc.html http://www.cyberciti.biz/tips/linux-as-router-for-dsl-t1-line-etc.html#comments Tue, 23 Nov 2004 21:22:00 +0000 nixcraft http://www.cyberciti.biz/tips/linux-as-router-for-dsl-t1-line-etc.html [...]]]> http://www.cyberciti.biz/tips/linux-as-router-for-dsl-t1-line-etc.html/feed 25