“tail -f” vs “tail -F”: Do you know the difference?

Hi all!
Do you know the difference between “tail -f” and “tail -F”?

duvida

Ok, don’t feel bad. It’s very difficult to find someone who knows… And with a reason, I can’t find any link explaining this by Googling.
It’s possible that I don’t know how to search it too. But I searched as I’d search if I didn’t know that… And couldn’t find anything about…

Let’s take a look on –help, so:

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Avoiding lost messages in JDBC Persistent Store, when processing Global Transactions with JMS.

   A few months ago, i had a problem in Persistence Store of JMS queues, soon after perform server restart, I get error from persistence store to recover message:

weblogic.store.PersistentStoreFatalException: [Store:280064]invalid handle 55981 (server="EVENTS01" store="JDBCStore_3022" table="JDBCStore_3022WLStore"),

   To resolve this problem, just add this parameter on server startup arguments:

 -Dweblogic.store.StoreBootOnError = true

   With this parameter, the server starts with OK status in WebLogic 11g and with FAILED status in Weblogic 12c, but in both the processing of the messages continues when active,
to remove FAILED status in Weblogic 12c, just need to truncate persistence table in database and restart server (This solution can be found in Oracle Docs).

   This solution did not solved my problem, because I can’t lost or delete messages.

Let’s go analyse the problem:

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Apache 2.4 with port redirect to Weblogic 12c

According Oracle guys, Apache 2.4 its is a vanila module to Weblogic 12c and same module runs with Weblogic 11g.

Modules are available to download:  https://blogs.oracle.com/WebLogicServer/entry/announcing_web_socket_proxy_and

# httpd -version
Server version: Apache/2.4.6 (Red Hat Enterprise Linux)
Server built:   Mar 21 2016 02:33:00

On httpd.conf is necessary to load Apache 2.4 module

LoadModule weblogic_module modules/lib/mod_wl_24.so

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Configuration Coherence Server Out-of-Process in OSB 12C

Hello guys,

Today I’m going to introduce the Coherence Server Out-of-Process configuration.
Once this configuration has changed a lot between versions 11G to 12C, the post will be a little bit more detailed (than usual).

The table below summarize these changes:

From To
 osb-coherence-cache-config.xml Coherence Cache Config resource
 osb-coherence-override.xml Coherence Cluster resoruce
Out-Of-Process Cache Server New WLS node/cluster

Follow the steps:

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Flashback – Part 5 (Flashback Table)

Hi everybody,

Today we are going to discuss about FLASHBACK TABLE. As usual, first, I am tagging here the previous posts about Flashback Technology, so feel free to check it out if you want:

Flashback – Part 1 (Flashback Drop)
Flashback – Part 2 (Flashback Query)
Flashback – Part 3 (Flashback Versions Query)
Flashback – Part 4 (Flashback Transaction Query)

So let’s do it people.

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RHEL7: rc.local service not starting

It’s very common to automate application startup in rc.local on Linux systems.

Was testing Red Hat 7.2 (Maipo), and found that apps was’t started.

Found this on some Red Hat blog: 

Systemd is a system and service manager for Linux operating systems. It is designed to be backwards compatible with SysV init scripts, and provides a number of features such as parallel startup of system services at boot time, on-demand activation of daemons, support for system state snapshots, or dependency-based service control logic. In Red Hat Enterprise Linux 7, systemd replaces Upstart as the default init system.”

On default /etc/rc.local comes useful info:

#!/bin/bash
# THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES
#
# It is highly advisable to create own systemd services or udev rules
# to run scripts during boot instead of using this file.
#
# In contrast to previous versions due to parallel execution during boot
# this script will NOT be run after all other services.
#
# Please note that you must run ‘chmod +x /etc/rc.d/rc.local’ to ensure
# that this script will be executed during boot.

touch /var/lock/subsys/local

Then, this ‘chmod’ turns rc.local enable during system startup.

 

To familiarize this new feature:

[root@somesystem~]# systemctl status rc-local
● rc-local.service - /etc/rc.d/rc.local Compatibility
Loaded: loaded (/usr/lib/systemd/system/rc-local.service; static; vendor preset: disabled)
Active: active (running) since Mon 2016-07-11 13:16:18 BRT; 28min ago
Process: 1046 ExecStart=/etc/rc.d/rc.local start (code=exited, status=0/SUCCESS)
CGroup: /system.slice/rc-local.service
├─2272 /bin/sh /oracle/domains/mywl_domain/startWebLogic.sh
├─2284 /bin/sh /oracle/domains/mywl_domain/bin/startWebLogic.sh
├─2374 /bin/sh /oracle/domains/mywl_domain/bin/startNodeManager.sh
├─2377 /bin/sh /oracle/binaries/wlserver/server/bin/startNodeManager.sh
├─2428 /oracle/jdk1.7.0_25/bin/java -Dwls.home=/oracle/binaries/wlserver/server -Dweblogic.home=/oracle/binaries/wlserver/server -server -Xms1g -Xmx1g -XX:MaxPermSize=512m -Dcoherence...
└─2442 /oracle/jdk1.7.0_25/bin/java -server -Xms1g -Xmx1g -XX:MaxPermSize=512m -Dweblogic.Name=AdminServer -Djava.security.policy=/oracle/binaries/wlserver/server/lib/weblogic.policy .

Maiquel.