Best practices for application account management is to have all application dependent accounts and groups local to the server. These accounts should be locked, so no interactive logins can happen. Ssh keys could still be used for automation from trusted…
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Sar Grapher Updated
Sar Grapher has been updated. It now graphs Linux NFS Server performance data.
Sun/Oracle Java Default Values
/opt/java/jdk1.6.0_21/bin/java -XX:+PrintFlagsFinal -version [Global flags] uintx AdaptivePermSizeWeight = 20 {product} uintx AdaptiveSizeDecrementScaleFactor = 4 {product} uintx AdaptiveSizeMajorGCDecayTimeScale = 10 {product} uintx AdaptiveSizePausePolicy = 0 {product} uintx AdaptiveSizePolicyCollectionCostMargin = 50 {product} uintx AdaptiveSizePolicyInitializingSteps = 20 {product} uintx AdaptiveSizePolicyOutputInterval = 0 {product}…
Getting JVM config
Use jmap to get a running JVM configuration For example: <path2java>/bin/jmap -heap <pid> JVM version is 17.0-b16 using parallel threads in the new generation. using thread-local object allocation. Concurrent Mark-Sweep GC Heap Configuration: MinHeapFreeRatio = 40 MaxHeapFreeRatio =…
Sargrapher Now Graphs Total CPU time
Sar grapher now displays graphs of total CPU time used. This makes it more obvious of combination of user, system, I/O wait.
Quering Oracle DB version
select * from sys.v_$version;
JVM Heap and Thread Dumps
Thread dump from a running JVM to a file, the -J-64 is 64bit JVMs: jmap -J-d64 -dump:format=b,file=<file> <pid> Thread dump from a running JVM to stderr of the process: kill -3 <pid> Heap dump from a running JVM, the -J-64…
Lunix Core Files
To enable core file generation.. Configure core files to use the PID as a extension. Set “kernel.core_uses_pid = 1” in /etc/sysctl.conf and run “/sbin/sysctl -p /etc/sysctl.conf: or to add it temporarily run “/sbin/sysctl -w kernel.core_uses_pid=1” to change the running kernel. …
Changing HTML Hyperlinks wih CSS
To change a hyperlink with CSS change the a:link Like: a:link { color: ff9900; font-family: arial; font-weight: bolder; font-size: 12; text-align: center; {
How to Reduce/Shrink a ext[234] File System
In order to shrink a file system, the file system must be unmounted. For example with a LVM Logical volume called testfilesystem in volume group testVG mount on /opt/testfilesystem ( /dev/testVG-testfilesystem or /dev/mapper/testVG-testfilesystem) that we want to make 162 GB in sise. First…