LINUX
« Previous EntriesLinux : Adding a Directory to the Path
Wednesday, November 4th, 2009The best place to add a directory to the path of a single user is to modify that user’s .bash_profile file. To add it to all users except user root, add it to /etc/profile. To also add it to the path of user root, add it to root’s .bash_profile file.
vi editing mode quick reference
Friday, October 30th, 2009Shortcut Description Switching to COMMAND Mode: ESC Switch to command mode. Commands for Entering INPUT Mode: i Insert before cursor. a Insert after cursor. I Insert at [...]
Linux Oracle tuning parameter : Shutdown GUI
Friday, June 5th, 2009Modify the ‘inittab’ file to set boot level as 3:
Linux Oracle tuning parameter : Disable Unnecessary Daemons
Friday, June 5th, 2009/sbin/chkconfig –levels 2345 sendmail off /sbin/chkconfig sendmail off
Linux Oracle tuning parameter : Tune TCP
Friday, June 5th, 2009To view current TCP settings, run command: sysctl net.ipv4.tcp_keepalive_time net.ipv4.tcp_keepalive_time = 7200 // 2 hours where net.ipv4.tcp_keepalive_time is a TCP tuning parameter. To set a TCP parameter to a value, run command: sysctl -w net.ipv4.tcp_keepalive_time=1800
Linux vs. Oracle Tuning, Error : ORA-00845: MEMORY_TARGET not supported on this system
Friday, June 5th, 2009The ORA-00845:can arises for the following two reasons on linux system. 1)If the shared memory which is mapped to /dev/shm directory is less than the size of MEMORY_TARGET or MEMORY_MAX_TARGET. or, 2)If the shared memory is not mapped to /dev/shm directory. Make sure /dev/shm is properly mounted. You can see it by, df -h Filesystem [...]
Linux Oracle tuning parameter : Message queues
Friday, June 5th, 2009To view current settings, run command: more /proc/sys/kernel/msgmni more /proc/sys/kernel/msgmax To set it to a new value for this running session, which takes effect immediately, run command: echo 2048 > /proc/sys/kernel/msgmni echo 64000 > /proc/sys/kernel/msgmax
Linux Oracle tuning parameter : shmmax and shmall
Friday, June 5th, 2009maximum amount of memory = shmall * pagesize where pagesize = getconf PAGE_SIZE and shmall = cat /proc/sys/kernel/shmall
Linux Oracle tuning parameter : Semaphores
Friday, June 5th, 2009To view current settings, run command: more /proc/sys/kernel/sem 250 32000 32 1024 To set it to a new value for this running session, which takes effect immediately, run command: echo 500 512000 64 2048 > /proc/sys/kernel/sem Parameters meaning: SEMMSL – semaphores per ID SEMMNS – (SEMMNI*SEMMSL) max semaphores in system SEMOPM – max operations per [...]
Linux Oracle tuning parameter : Shared Memory
Friday, June 5th, 2009To view current settings, run command: more /proc/sys/kernel/shmmax To set it to a new value for this running session, which takes effect immediately, run command: echo 268435456 > /proc/sys/kernel/shmmax To set it to a new value permanently (so it survives reboots), modify the sysctl.conf file: … kernel.shmmax = 268435456
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