服务器每隔一段时间后就出现无法登陆的问题。重启数据库后，问题解决，但这并不是长久之计。查看日志文件：D:\app\administrator\diag\rdbms\hzdb\hzdb\alert的alert.log,出现大量的重复错误信息，如下所示：Client address: (ADDRESS=(PROTOCOL=tcp)(HOST=172.16.206.83)(PORT=2067))   TNS-00505: 操作超时 nt secondary err code: 60  nt OS err code: 0  ns secondary err code: 12560  nt main err code: 505  TNS-12535: TNS: 操作超时  Tracing not turned on.  Tns error struct:ns main err code: 12535  VERSION INFORMATION: TNS for 32-bit Windows: Version 11.1.0.7.0 - Production Oracle Bequeath NTProtocol Adapter for 32-bit Windows: Version 11.1.0.7.0 - Production Windows NT TCP/IP NT ProtocolAdapter for 32-bit Windows: Version 11.1.0.7.0 - Production  Fatal NI connect error 12170.为什么会出现这样的情况呢？网上搜索后得知，在Oracle11G中，有这样两个参数SQLNET.INBOUND_CONNECT_TIMEOUT 和INBOUND_CONNECT_TIMEOUT_list...

10.2. Changing Network Kernel SettingsOracle now uses User Datagram Protocol (UDP) as the default protocol on Linux for interprocess communication, such as cache fusion buffer transfers between the instances. However, starting with Oracle 10g network settings should be adjusted for standalone databases as well.Oracle recommends the default and maximum send buffer size (SO_SNDBUF socket option) and receive buffer size (SO_RCVBUF socket option) to be set to 256 KB. The receive buffers are used by TCP and UDP to hold received data until it is read by the application. The receive buffer cannot overflow because the peer is not allowed to send data beyond the buffer size window. This means that datagrams will be discarded if they do not fit in the socket receive buffer. This could cause the sender to overwhelm the receiver.The default and maximum window size can be changed in the proc file system without reboot:The default setting in bytes of the socket receive buffer:# sysctl -w net.c...

How To: Network / TCP / UDP TuningThis is a very basic step by step description of how to improve the performancenetworking (TCP & UDP) on Linux 2.4+ for high-bandwidth applications. These settings are especiallyimportant for GigE links. Jump to Quick Step or All The Steps.AssumptionsThis howto assumes that the machine being tuned is involved in supporting high-bandwidthapplications. Making these modifications on a machine that supports multiple users and/ormultiple connections is not recommended - it may cause the machine to deny connectionsbecause of a lack of memory allocation.The StepsMake sure that you have root privleges.Type: sysctl -p | grep memThis will display your current buffer settings. Save These! You may want toroll-back these changesType: sysctl -w net.core.rmem_max=8388608 This sets the max OS receive buffer size for all types of connections.Type: sysctl -w net.core.wmem_max=8388608 This sets the max OS send buffer size for all types of connections.Type...

之前安装好 zabbix3.2与oracle，具体详见：http://www.micoder.cc/blog/1953.html需要添加服务器的应用服务的日志监控与系统登陆信息监控，这里就作一个简单的例子。在zabbix上配置监控主机后，添加监控项目：监控日志key首先要了解key，log[ file  ,<regexp>,<encoding>,<maxlines>,<mode>,<output>]file：文件名，写绝对路径regexp：要匹配内容的正则表达式，或者直接写你要检索的内容也可以，例如我想检索带ERROR关键词的记录encoding：编码相关，留空即可maxlines：一次性最多提交多少行，这个参数覆盖配置文件zabbxi_agentd.conf中的’MaxLinesPerSecond’，我们也可以留空mode：默认是all，也可以是skip，skip会跳过老数据output：输出给zabbix server的数据。可以是\1、\2一直\9，\1表示第一个正则表达式匹配出得内容，\2表示第二个正则表达式匹配错的内容。项目：oracle_error_log类型 ： zabbix agent（active）键值   ：  log[/data/app/oracle/diag/rdbms/hextrack/hextrack/trace/alert_hextrack.log,"Warning|ORA\-",gbk,,,]这里是监控oracle告警文件中Warning或是ORA-开头的内容，采用GBK编码。信...

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Log file monitoringOverviewZabbix can be used for centralized monitoring and analysis of log files with/without log rotation support. Notifications can be used to warn users when a log file contains certain strings or string patterns.To monitor a log file you must have: Zabbix agent running on the host log monitoring item set upThe size limit of a monitored log file depends on large file support.ConfigurationVerify agent parametersMake sure that in the agent configuration file: 'Hostname' parameter matches the host name in the frontend Servers in the 'ServerActive' parameter are specified for the processing of active checksItem configurationConfigure a log monitoring item: Specifically for log monitoring items you enter:TypeSelect Zabbix agent (active) here.KeySet either:log[/path/to/file/file_name,<regexp>,<encoding>,<maxlines>,<mode>,<output>,<maxdelay>]orlogrt[/path/to/file/regexp_describing_filename_pattern,<regexp>,<encoding>,<ma...

zabbix agent/3.0Contents1 Zabbix agent protocol1.1 Active agents1.1.1 Items to be monitored exist1.1.2 No active items1.1.3 Host does not exist1.1.4 Host not monitored1.1.5 Meta information updateZabbix agent protocolActive agents Note: Also see the description in the zabbix manualWhen an active agent starts, it connects to the server to ask for any item it should be monitoring:{ "request":"active checks", "host":"Host name" } If host has metadata to send, it is included in this request:{ "host": "Host name", "host_metadata": "apache|mysql|postfix", "request": "active checks" } If host has non-default listen IP or port set, they are included in this request:{ "host": "Host name", "ip": "127.0.0.1", "port": 10055, "request": "active checks" } Items ...

tag@cwtdb2 ~]$ free -g-bash: fork: Cannot allocate memoryThere is also /proc/sys/kernel/pid_max file, which specifies the value at which PIDs wrap around (i.e., the value in this file is one greater than the maximum PID). The default value for this file, 32768, results in the same range of PIDs as on earlier kernels (<=2.4). The value in this file can be set to any value up to 2^22 (PID_MAX_LIMIT, approximately 4 million). Increasing the value will help on large Linux system or clusters to ease process identification and process management. You can easily prevent fork() failures error message with this hack. Display Current Process Identifiers Limit On a Linux Based SystemsType the following command at shell prompt: $ sysctl kernel.pid_max OR $ cat /proc/sys/kernel/pid_max OR $ sysctl kernel.pid_max Sample outputs:kernel.pid_max = 32768Allow for more PIDs on a Linux based systemsup to 222 = 4,194,304Type the following command: # sysctl -w kernel.pid_max=4194303 OR # echo 4194303 ...

Oracle在10g中引入了闪回区(flash recovery area)的概念，用以简化和完善备份，但是闪回区同样需要精心规划和设置，否则一样会遇到问题，从Oracle10gR2开始，Oracle还提供了一个新的视图V$FLASH_RECOVERY_AREA_USAGE，用以监控闪回区空间的耗用情况。本文简要介绍Oracle闪回区的警报和空间维护机制。每次RMAN在闪回区(flash recovery area)创建文件时，会同时更新可删除文件列表。当闪回区存在空间压力时，Oracle会自动从闪回区中删除废弃文件，当没有更多空间可以释放时，Oracle会给出空间压力警报。当空间使用达到100%，数据库将会因为无法归档等原因挂起。闪回区的大小由:db_recovery_file_dest_size 参数指定。路径由: db_recovery_file_dest 参赛指定。 SQL> show parameter db_recovery NAME                                 TYPE        VALUE ------------------------------------ ----------- ----------------------------...

应用部署到weblogic下（Tomcat下无问题），filter执行时报错： java.lang.IllegalStateException: Cannot resize buffer - 299 bytes have already been written (Servlet 2.3, sec. 5.1)at weblogic.servlet.internal.ServletResponseImpl.setBufferSize(ServletResponseImpl.java:346)at weblogic.servlet.jsp.PageContextImpl.initialize(PageContextImpl.java:74)at weblogic.servlet.jsp.PageContextImpl.<init>(PageContextImpl.java:110)at weblogic.servlet.jsp.JspFactoryImpl.getPageContext(JspFactoryImpl.java:40)at jsp_servlet.__index._jspService(__index.java:65)原因：调用了response.sendRedirect()之后，再调用了filterChain.doFilter(request, response)解决：修改代码，确保 sendRedirect 之后 return 或 doFilter 之前无 sendRedirect。Jetty下，post 1个表单数据时报错： java.lang.IllegalStateException: Form too large210799>200000原因： Jetty对form post data的大小有限制，默认为200000bytes解决： 修改Jetty的默认限制值。1. Jetty: 默认限制为200000bytes(约200KB).修改默认限制值的方法如下：参考：http:/...