Oracle Database Startup and Shutdown Procedure

Posted on December 27, 2010 by jlim0930

thanks the geek stuff

How To Startup Oracle Database

1. Login to the system with oracle username

Typical oracle installation will have oracle as username and dba as group. On Linux, do su to oracle as shown below.

$ su - oracle

2. Connect to oracle sysdba

Make sure ORACLE_SID and ORACLE_HOME are set properly as shown below.

$ env | grep ORA
ORACLE_SID=DEVDB
ORACLE_HOME=/u01/app/oracle/product/10.2.0



You can connect using either “/ as sysdba” or an oracle account that has DBA privilege.

$ sqlplus '/ as sysdba'
SQL*Plus: Release 10.2.0.3.0 - Production on Sun Jan 18 11:11:28 2009
Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.

Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.3.0 - Production
With the Partitioning and Data Mining options
SQL>

3. Start Oracle Database

The default SPFILE (server parameter file) is located under $ORACLE_HOME/dbs. Oracle will use this SPFILE during startup, if you don’t specify PFILE.



Oracle will look for the parameter file in the following order under $ORACLE_HOME/dbs. If any one of them exist, it will use that particular parameter file.

  1. spfile$ORACLE_SID.ora
  2. spfile.ora
  3. init$ORACLE_SID.ora



Type “startup” at the SQL command prompt to startup the database as shown below.

SQL> startup
ORACLE instance started.

Total System Global Area  812529152 bytes
Fixed Size                  2264280 bytes
Variable Size             960781800 bytes
Database Buffers           54654432 bytes
Redo Buffers                3498640 bytes
Database mounted.
Database opened.
SQL>



If you want to startup Oracle with PFILE, pass it as a parameter as shown below.

SQL> STARTUP PFILE=/u01/app/oracle/product/10.2.0/dbs/init.ora

How To Shutdown Oracle Database

Following three methods are available to shutdown the oracle database:

  1. Normal Shutdown
  2. Shutdown Immediate
  3. Shutdown Abort

1. Normal Shutdown

During normal shutdown, before the oracle database is shut down, oracle will wait for all active users to disconnect their sessions. As the parameter name (normal) suggest, use this option to shutdown the database under normal conditions.

SQL> shutdown
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL>

2. Shutdown Immediate

During immediate shutdown, before the oracle database is shut down, oracle will rollback active transaction and disconnect all active users. Use this option when there is a problem with your database and you don’t have enough time to request users to log-off.

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL>

3. Shutdown Abort

During shutdown abort, before the oracle database is shutdown, all user sessions will be terminated immediately. Uncomitted transactions will not be rolled back. Use this option only during emergency situations when the “shutdown” and “shutdown immediate” doesn’t work.

$ sqlplus '/ as sysdba'
SQL*Plus: Release 10.2.0.3.0 - Production on Sun Jan 18 11:11:33 2009
Copyright (c) 1982, 2006, Oracle.  All Rights Reserved.
Connected to an idle instance.

SQL> shutdown abort
ORACLE instance shut down.
SQL>
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9 Linux ethtool Examples to Manipulate Ethernet Card (NIC Card)

Posted on December 27, 2010 by jlim0930

Thanks to the geek stuff

1. List Ethernet Device Properties

When you execute ethtool command with a device name, it displays the following information about the ethernet device.

# ethtool eth0
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Advertised auto-negotiation: Yes
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: on
        Supports Wake-on: d
        Wake-on: d
        Link detected: yes

This above ethtool output displays ethernet card properties such as speed, wake on, duplex and the link detection status. Following are the three types of duplexes available.

  • Full duplex : Enables sending and receiving of packets at the same time. This mode is used when the ethernet device is connected to a switch.
  • Half duplex : Enables either sending or receiving of packets at a single point of time. This mode is used when the ethernet device is connected to a hub.
  • Auto-negotiation : If enabled, the ethernet device itself decides whether to use either full duplex or half duplex based on the network the ethernet device attached to.

2. Change NIC Parameter Using ethtool Option -s autoneg

The above ethtool eth0 output displays that the “Auto-negotiation” parameter is in enabled state. You can disable this using autoneg option in the ethtool as shown below.

# ifdown eth0
    eth0      device: Broadcom Corporation NetXtreme II BCM5709 Gigabit Ethernet (rev 20)
    eth0      configuration: eth-bus-pci-0000:0b:00.0

# ethtool  -s eth0 autoneg off

# ethtool eth0
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  Not reported
        Advertised auto-negotiation: No
        Speed: Unknown! (65535)
        Duplex: Unknown! (255)
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: off
        Supports Wake-on: g
        Wake-on: g
        Link detected: no
# ifup eth0

After the above change, you could see that the “link detection” value changed to down and auto-negotiation is in off state.

3. Change the Speed of Ethernet Device

Using ethtool you can change the speed of the ethernet device to work with the certain network devices, and the newly assign speed value should be within the limited capacity.

# ethtool -s eth0 speed 100 autoneg off

# ethtool eth0
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  Not reported
        Advertised auto-negotiation: No
        Speed: Unknown! (65535)
        Duplex: Unknown! (255)
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: off
        Supports Wake-on: g
        Wake-on: g
        Link detected: no

Once you change the speed when the adapter is online, it automatically goes offline, and you need to bring it back online using ifup command.

# ifup eth0
    eth0      device: Broadcom Corporation NetXtreme II BCM5709 Gigabit Ethernet (rev 20)
    eth0      configuration: eth-bus-pci-0000:0b:00.0
Checking for network time protocol daemon (NTPD):                     running

# ethtool eth0
Settings for eth0:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
        Supports auto-negotiation: Yes
        Advertised link modes:  Not reported
        Advertised auto-negotiation: No
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: off
        Supports Wake-on: g
        Wake-on: g
        Link detected: yes

As shown in the above output, the speed changed from 1000Mb/s to 100Mb/s and auto-negotiation parameter is unset.

To change the Maximum Transmission Unit (MTU), refer to our ifconfig examples article.

4. Display Ethernet Driver Settings

ethtool -i option displays driver version, firmware version and bus details as shown below.

# ethtool -i eth0
driver: bnx2
version: 2.0.1-suse
firmware-version: 1.9.3
bus-info: 0000:04:00.0

5. Display Auto-negotiation, RX and TX of eth0

View the autonegotiation details about the specific ethernet device as shown below.

# ethtool -a eth0
Pause parameters for eth0:
Autonegotiate:  on
RX:             on
TX:             on

6. Display Network Statistics of Specific Ethernet Device

Use ethtool -S option to display the bytes transfered, received, errors, etc, as shown below.

# ethtool -S eth0
NIC statistics:
     rx_bytes: 74356477841
     rx_error_bytes: 0
     tx_bytes: 110725861146
     tx_error_bytes: 0
     rx_ucast_packets: 104169941
     rx_mcast_packets: 138831
     rx_bcast_packets: 59543904
     tx_ucast_packets: 118118510
     tx_mcast_packets: 10137453
     tx_bcast_packets: 2221841
     tx_mac_errors: 0
     tx_carrier_errors: 0
     rx_crc_errors: 0
     rx_align_errors: 0
     tx_single_collisions: 0
     tx_multi_collisions: 0
     tx_deferred: 0
     tx_excess_collisions: 0
     tx_late_collisions: 0
     tx_total_collisions: 0
     rx_fragments: 0
     rx_jabbers: 0
     rx_undersize_packets: 0
     rx_oversize_packets: 0
     rx_64_byte_packets: 61154057
     rx_65_to_127_byte_packets: 55038726
     rx_128_to_255_byte_packets: 426962
     rx_256_to_511_byte_packets: 3573763
     rx_512_to_1023_byte_packets: 893173
     rx_1024_to_1522_byte_packets: 42765995
     rx_1523_to_9022_byte_packets: 0
     tx_64_byte_packets: 3633165
     tx_65_to_127_byte_packets: 51169838
     tx_128_to_255_byte_packets: 3812067
     tx_256_to_511_byte_packets: 113766
     tx_512_to_1023_byte_packets: 104081
     tx_1024_to_1522_byte_packets: 71644887
     tx_1523_to_9022_byte_packets: 0
     rx_xon_frames: 0
     rx_xoff_frames: 0
     tx_xon_frames: 0
     tx_xoff_frames: 0
     rx_mac_ctrl_frames: 0
     rx_filtered_packets: 14596600
     rx_discards: 0
     rx_fw_discards: 0

7. Troubleshoot the Ethernet Connection Issues

When there is a problem with the network connection, you might want to check (or change) the ethernet device parameters explained in the above examples, when you see following issues in the output of ethtool command.

  • Speed and Duplex value is shown as Unknown
  • Link detection value is shown as No

Upon successful connection, the three parameters mentioned above gets appropriate values. i.e Speed is assigned with known value, Duplex become either Full/Half, and the Link detection becomes Yes.

After the above changes, if the Link Detection still says “No”, check whether there are any issues in the cables that runs from the switch and the system, you might want to dig into that aspect further.

To capture and analyze packets from a specific network interface, use tcpdump utility.

8. Identify Specific Device From Multiple Devices (Blink LED Port of NIC Card)

Let us assume that you have a machine with four ethernet adapters, and you want to identify the physical port of a particular ethernet card. (For example, eth0).

Use ethtool option -p, which will make the corresponding LED of physical port to blink.

# ethtool -p eth0

9. Make Changes Permanent After Reboot

If you’ve changed any ethernet device parameters using the ethtool, it will all disappear after the next reboot, unless you do the following.

On ubuntu, you have to modify /etc/network/interfaces file and add all your changes as shown below.

# vim /etc/network/interfaces
post-up ethtool -s eth2 speed 1000 duplex full autoneg off

The above line should be the last line of the file. This will change speed, duplex and autoneg of eth2 device permanently.

On SUSE, modify the /etc/sysconfig/network/ifcfg-eth-id file and include a new script using POST_UP_SCRIPT variable as shown below. Include the below line as the last line in the corresponding eth1 adpater config file.

# vim /etc/sysconfig/network/ifcfg-eth-id
POST_UP_SCRIPT='eth1'

Then, create a new file scripts/eth1 as shown below under /etc/sysconfig/network directory. Make sure that the script has execute permission and ensure that the ethtool utility is present under /sbin directory.

# cd /etc/sysconfig/network/

# vim scripts/eth1
#!/bin/bash
/sbin/ethtool -s duplex full speed 100 autoneg off
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Linux modprobe Command Examples to View, Install, Remove Modules

Posted on December 27, 2010 by jlim0930

Thanks to the geek stuff

modprobe utility is used to add loadable modules to the Linux kernel. You can also view and remove modules using modprobe command.

Linux maintains /lib/modules/$(uname-r) directory for modules and its configuration files (except /etc/modprobe.conf and /etc/modprobe.d).

In Linux kernel 2.6, the .ko modules are used instead of .o files since that has additional information that the kernel uses to load the modules. The example in this article are done with using modprobe on Ubuntu.

1. List Available Kernel Modules

modprobe -l will display all available modules as shown below.

$ modprobe -l | less
kernel/arch/x86/kernel/cpu/mcheck/mce-inject.ko
kernel/arch/x86/kernel/cpu/cpufreq/e_powersaver.ko
kernel/arch/x86/kernel/cpu/cpufreq/p4-clockmod.ko
kernel/arch/x86/kernel/msr.ko
kernel/arch/x86/kernel/cpuid.ko
kernel/arch/x86/kernel/apm.ko
kernel/arch/x86/kernel/scx200.ko
kernel/arch/x86/kernel/microcode.ko
kernel/arch/x86/crypto/aes-i586.ko
kernel/arch/x86/crypto/twofish-i586.ko

2. List Currently Loaded Modules

While the above modprobe command shows all available modules, lsmod command will display all modules that are currently loaded in the Linux kernel.

$ lsmod | less
soundcore          7264   1 snd
ppdev                6688   0
snd_page_alloc   9156    1 snd_pcm
psmouse            56180  0
lp                     8964    0

3. Install New modules into Linux Kernel

In order to insert a new module into the kernel, execute the modprobe command with the module name.

Following example loads vmhgfs module to Linux kernel on Ubuntu.

$ sudo modprobe vmhgfs

Once a module is loaded, verify it using lsmod command as shown below.

$ lsmod | grep vmhgfs
vmhgfs                 50772  0

The module files are with .ko extension. If you like to know the full file location of a specific Linux kernel module, use modprobe command and do a grep of the module name as shown below.

$ modprobe | grep vmhgfs
misc/vmhgfs.ko

$ cd /lib/modules/2.6.31-14-generic/misc

$ ls vmhgfs*
vmhgfs.ko

Note: You can also use insmod for installing new modules into the Linux kernel.

4. Load New Modules with the Different Name to Avoid Conflicts

Consider, in some cases you are supposed to load a new module but with the same module name another module got already loaded for different purposes.

If for some strange reasons, the module name you are trying to load into the kernel is getting used (with the same name) by a different module, then you can load the new module using a different name.

To load a module with a different name, use the modprobe option -o as shown below.

$ sudo modprobe vmhgfs -o vm_hgfs

$ lsmod  | grep vm_hgfs
vm_hgfs                   50772  0

5. Remove the Currently Loaded Module

If you’ve loaded a module to Linux kernel for some testing purpose, you might want to unload (remove) it from the kernel.

Use modprobe -r option to unload a module from the kernel as shown below.

modprobe -r vmhgfs
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