Friday, July 26, 2013

Oracle Database Preinstallation – Part 4

Dear Readers,

My name is Franz Devantier, creator of this blog.  I am an Oracle Certified Professional (OCP DBA 11g) Security DBA.  I will be sharing with you the basic duties of an Oracle DBA, and also some of the undocumented, and not so well known tasks. 

I will make a deal with you:  If you refer me to a company that needs database support, from a few hours per week to full time, and I am able to sign a contract with them.
Then I will give you 10% of the monthly contract or deal price every month.  When the contract ends, and we re-sign the contract, I will again give you 10% of the monthly contract price.  This will go on until the company no longer employs or contracts me or my agents to look after their databases.
I can do this, because that 10% is my marketing budget.  When we re-sign the contract, in the future, it may depend on you giving the thumbs up again, and that is worth 10% of the monthly contract price, to be given to you as commission.

Oracle Database Preinstallation – Part 4
Kernel Requirements
For Oracle Database Server 11.2, there are the following kernel requirements
Linux x86
Linux x86
Kernel
On Oracle Linux 4 and red Hat Enterprise Linux 4
2.6.9 or later
On Asianux Server 3, Oracle Linux 5, and Red Hat Enterprise Linux 5
2.6.18 or later
On SUSE Linux Enterprise Server 10
2.6.16.21
On SUSE Linux Enterprise Server 11
2.6.27.19

Linux x86-64
Linux x86-64
Kernel
On Oracle Linux 4 and Red Hat Enterprise Linux 4
2.6.9 or later
On Oracle Linux 5 Update 5
2.6.32-100.0.19 or later
On Oracle Linux 5 Update 2
2.6.18 or later (with Red Hat Compatible Kernel)
On Oracle Linux 6
2.6.32-100.28.5.el6.x86_64 or later
On Oracle Linux 6
2.6.32-71.el6.x86_64 or later (with Red Hat Compatible Kernel)
On Red Hat Enterprise Linux 5 Update 5 with the Oracle Unbreakable Enterprise Kernel for Linux
2.6.32 or later
On Red Hat Enterprise Linux 6 with the Oracle Unbreakable Enterprise Kernel for Linux
2.6.32-100.28.5.el6.x86_64 or later
On Red Hat Enterprise Linux 6
2.6.32-71.el6.x86_64 or later
On Asianux Server 3, Oracle Linux 5 Update 2, and Red Hat Enterprise Linux 5 Update 2
2.6.18 or later
On SUSE Linux Enterprise Server 10
2.6.16.21 or later
On SUSE Linux Enterprise Server 11
2.6.27.19 or later


IBM: Linux on System z
IBM: Linux on System z
Kernel
On Red Hat Enterprise Linux 4
2.6.9 or later
On Red Hat Enterprise Linux 5
2.6.18 or later
On SUSE Linux Enterprise Server 10
2.6.16.60 or later
On SUSE Linux Enterprise Server 11
2.6.32.12 or later

To determine if the required kernel is installed, enter the following command:
$ uname -r

You could expect output similar to the below, which was run from a shell on an Oracle Linux 5 system:

2.6.18-128.el5PAE

You see that the Kernel version is “2.6.18” and that the errata level is “-128.el5PAE”

If your kernel version is not up to specifications, then you will have to contact the operating system vendor, for further information about obtaining and installing the correct Kernel updates.


Package Requirements
The following are the list of packages required for Oracle Database 11g Release 2 (11.2):
We are just going to look at the package requirements for Oracle Linux x86_64.  If you are using a different Operating system, then you can look in the Oracle Installation Guides for the appropriate information.

Oracle recommends that you install your Linux operating system with the default software packages, which are also known as RPM’s.  It is best not to customize the RPM’s during a default Operating System installation.  If you use the default installation, then most of the RPM’s or packages that you will need to install Oracle will already be installed.  One of the big things with packages is the package dependencies.  Installing a package with multiple package dependencies, who may also have dependencies, is something that you want to minimize if possible.

Sometimes you get to an installation and the operating system is already installed, and not a default installation.  Also if you want to use LDAP, or you want to run certain scripts, for example: odisrvreg, oidca, or schemasync; then you can install the Korn shell RPM for the Linux distribution.

Below is a list of packages for Oracle Linux x86_64.  You must make sure that all these packages or RPM’s, and all of their prerequisites are properly installed.  If you can only find a later version of a package then that is generally ok, unless there are specific dependencies to other packeages.

I am looking at x86_64, because it just makes sense to migrate to a 64 bit environment.
Starting with Oracle 11.2.0.2, all the 32 bit packages with the exception of “gcc-32bit-4.3” are no longer required, but only the 64-bit RPM’s.  However if your database is a release prior to  11.2.0.2, then you will need to install both the 32 bit packages, and the 64 bit packages.

Oracle Database Package Requirements for Linux x86-64
Operating System
Package RPM – requirement
Oracle Linux 4, red Hat Enterprise Linux 4
The following packages (or later versions) must be installed:
binutils-2.15.92.0.2
compat-libstdc++-33-3.2.3
compat-libstdc++-33-3.2.3 (32 bit)
elfutils-libelf-0.97
elfutils-libelf-devel-0.97
expat-1.95.7
gcc-3.4.6
gcc-c++-3.4.6
glibc-2.3.4-2.41
glibc-2.3.4-2.41 (32 bit)
glibc-common-2.3.4
glibc-devel-2.3.4
glibc-headers-2.3.4
libaio-0.3.105
libaio-0.3.105 (32 bit)
libaio-devel-0.3.105
libaio-devel-0.3.105 (32 bit)
libgcc-3.4.6
libgcc-3.4.6 (32-bit)
libstdc++-3.4.6
libstdc++-3.4.6 (32 bit)
libstdc++-devel 3.4.6
make-3.80
numactl-0.6.4.x86_64
pdksh-5.2.14
sysstat-5.0.5
Operating System
Package RPM – requirement
Asianux Server 3, Oracle Linux 5, and Red Hat Enterprise Linux 5
The following packages (or later versions) must be installed:
binutils-2.17.50.0.6
compat-libstdc++-33-3.2.3
compat-libstdc++-33-3.2.3 (32 bit)
elfutils-libelf-0.125
elfutils-libelf-devel-0.125
gcc-4.1.2
gcc-c++-4.1.2
glibc-2.5-24
glibc-2.5-24 (32 bit)
glibc-common-2.5
glibc-devel-2.5
glibc-devel-2.5 (32 bit)
glibc-headers-2.5
ksh-20060214
libaio-0.3.106
libaio-0.3.106 (32 bit)
libaio-devel-0.3.106
libaio-devel-0.3.106 (32 bit)
libgcc-4.1.2
libgcc-4.1.2 (32 bit)
libstdc++-4.1.2
libstdc++-4.1.2 (32 bit)
libstdc++-devel 4.1.2
make-3.81
sysstat-7.0.2
Operating System
Package RPM – requirement
Oracle Linux 6 and Red Hat Enterprise Linux 6
The following packages (or later versions) must be installed:
binutils-2.20.51.0.2-5.11.el6 (x86_64)
compat-libcap1-1.10-1 (x86_64)
compat-libstdc++-33-3.2.3-69.el6 (x86_64)
compat-libstdc++-33-3.2.3-69.el6.i686
gcc-4.4.4-13.el6 (x86_64)
gcc-c++-4.4.4-13.el6 (x86_64)
glibc-2.12-1.7.el6 (i686)
glibc-2.12-1.7.el6 (x86_64)
glibc-devel-2.12-1.7.el6 (x86_64)
glibc-devel-2.12-1.7.el6.i686
ksh
libgcc-4.4.4-13.el6 (i686)
libgcc-4.4.4-13.el6 (x86_64)
libstdc++-4.4.4-13.el6 (x86_64)
libstdc++-4.4.4-13.el6.i686
libstdc++-devel-4.4.4-13.el6 (x86_64)
libstdc++-devel-4.4.4-13.el6.i686
libaio-0.3.107-10.el6 (x86_64)
libaio-0.3.107-10.el6.i686
libaio-devel-0.3.107-10.el6 (x86_64)
libaio-devel-0.3.107-10.el6.i686
make-3.81-19.el6
sysstat-9.0.4-11.el6 (x86_64)

Rpm, stands for RedHat Package Manager.  However rpm has been adopted by other Linux distributions as well.  RPM packages have the .rpm extension.  In Linux you need to be logged in as the root user, in order to install the rpm packages.

To install a software package you use the -i option, which tell the package manager to install the software.
$ rpm –i software-1.2.3.rpm

If the software is already installed on the operating system, and you just want to upgrade it, then you will use the -U switch.
$ rmp -U software-1.2.3.rpm

Executable programs that are installed with rpm, usually go into /bin,  /usr/bin,  /usr/X11/bin, or /usr/X11R6/bin

Usually you can run the program by simply typing it in your shell, so you don’t need to know where the program is installed, but only the program name.  The program may get added to your menu.

If you get a failed dependency error, then rpm also spools out a list of dependencies.  You will need to first download and install or upgrade these packages, before you can try the one which failed again.  It is also possible to install the package without the dependencies, although this is not recommended.
  $ rpm –i software-1.2.3.rpm  --nodeps

You can also install the package like this:
$ rpm -ivh software-1.2.3.rpm
. i = install
. v = verbose
. h = print hash marks as the package archive is unpacked

To remove or erase software that you previously installed with rpm you use the -e switch
$ rpm -e  software-1.2.3
Notice that you can leave the extension out, and even the version information if you like, or don’t know it.
$ rpm -e software
If you remove software with the rm command, then rpm will not remove the software from its database, which could lead to problems.

You can query the rpm database to see what software is there, for example:
$ rpm -q software
This will either confirm that the software is not installed, or return the version numbers.

You can generate a list of all the packages installed on your system with the -qa  switch, you will probably want to pipe this to “less”, so that you can examine the output.
$ rpm -qa | less

The -qa switch is also very useful for helping you to find packages with specific letters in them, for example:
$ rpm -qa |grep soft

Remember to look on the Linux distribution media first for the package, before downloading it from the Linux vendor’s web site.

Franz Devantier,
Need a database health check?
devantierf@gmail.com

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Wednesday, July 24, 2013

Oracle Database Preinstallation – Part 3

Dear Readers,

My name is Franz Devantier, creator of this blog.  I am an Oracle Certified Professional (OCP DBA 11g) Security DBA.  I will be sharing with you the basic duties of an Oracle DBA, and also some of the undocumented, and not so well known tasks. 


I will make a deal with you:  If you refer me to a company that needs database support, from a few hours per week to full time, and I am able to sign a contract with them.
Then I will give you 10% of the monthly contract or deal price every month.  When the contract ends, and we re-sign the contract, I will again give you 10% of the monthly contract price.  This will go on until the company no longer employs or contracts me or my agents to look after their databases.
I can do this, because that 10% is my marketing budget.  When we re-sign the contract, in the future, it may depend on you giving the thumbs up again, and that is worth 10% of the monthly contract price, to be given to you as commission.

Oracle Database Preinstallation – Part 3
Checking the Software Requirements
Depending on whether you are going to install, enterprise or standard edition, but really the other things that go with them.  Are you going to install grid control, ASM etc.  What add-ins are you going to install.  So this task is highly dependent on exactly what you will install, but the basic concepts are fairly generic as well.  We will need to look at the Operating system requirements, Kernel requirements, Package requirements, Compiler requirements, and additional Software requirements.

Oracle Universal Installer(OUI) will also perform a series of checks to make sure that you meet the minimal requirements.  It is better practice to first verify that your configuration has all the needed requirements, rather than allowing OUI to abend when it tries to install the Oracle software.

Operating System Requirements
We are installing the Oracle Linux OS by default, to run on x86-64.  This means that we can choose from Oracle Linux 4,5 or 6.  If your specific version of Linux is not on the list, then you will probably have great difficulty installing Oracle on the box, if you get it right at all.  You need to make sure that you have the correct update, and in addition you need to match your OS to your hardware.  Sometimes the issue may be because the specific version of Linux is not compatible on a specific hard platform.  Of course Linux versions like Ubuntu are unsupported at this point in time.  Although it may be possible with quite a bit of effort and research to get the Oracle database server to work on an unsupported version of Linux, it is strongly discouraged, especially in a production environment.

For Oracle database server 11.2 the following minimal operating systems are compatible.  Note that sometimes a more advanced Operating system is also not compatible.  This exercise where you verify or select you Operating System, is very important, if you want a successful Oracle database installation.

On Linux x86
Asianux Server 3 SP2
Oracle Linux 4 Update 7
Oracle Linux 5 Update 2
Red Hat Enterprise Linux 4 Update 7
Red Hat Enterprise Linux 5 Update 2
SUSE Linux Enterprise Server 10 SP2
SUSE Linux Enterprise Server 11
On Linux x86-64
Asianux Server 3 SP2
Oracle Linux 4 Update 7
Oracle Linux 5 Update 2 (with Red Hat Compatible Kernel)
Oracle Linux 5 Update 5
Oracle Linux 6
Oracle Linux 6 (with Red Hat Compatible Kernel)
Red Hat Enterprise Linux 4 Update 7
Red Hat Enterprise Linux 5 Update 2
Red Hat Enterprise Linux 5 Update 5 (with the Oracle Unbreakable Enterprise Kernel for Linux)
Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 6 (with the Oracle Unbreakable Enterprise Kernel for Linux)
SUSE Linux Enterprise Server 10 SP2
SUSE Linux Enterprise Server 11
On IBM: Linux on System z
Red Hat Enterprise Linux 4 Update 8
Red Hat Enterprise Linux 5 Update 4
SUSE Linux Enterprise Server 10 SP3
SUSE Linux Enterprise Server 11 SP1






From Oracle database Server 11.2 onwards, the Security Enhanced Linux feature (SELinux), is supported for Oracle Linux 4, Oracle Linux 5, Oracle Linux 6, Red Hat Enterprise Linux 4, red Hat Enterprise Linux 5, red Hat Enterprise Linux 6

When you are looking at the system requirements, by Kernel version, then the following notes will prove useful.
Oracle Linux 4 and red Hat Enterprise Linux 4, have the same requirements with regards to the kernel version.

Asianux Server 3, Oracle Linux 5, and Red Hat Enterprise Linux 5.  They all have the same Update 2 requirements.

Oracle Unbreakable Enterprise Kernel for x86-64 systems, for Linux 5 Update 5 (2.6.32) and above, contain several additional features and performance enhancements.  These features are not available with Oracle Linux or with other supported Linux distributions.  You can install this Oracle Unbreakable Enterprise kernel in certain situations.  Firstly you must be running on a x86-64 server.  Then it can be installed on the following Operating Systems: Oracle Linux 5 update 5, Oracle Linux 6, Red Hat Enterprise Linux 5 Update 5, or Red Hat Enterprise Linux 6.

If you are using Oracle Linux 6, then the Oracle Unbreakable Enterprise Kernel for Linux is installed by default.

You will need to determine the exact distribution and version of installed Linux, to make sure that you have a compatible operating system for the Oracle installation.
$ cat /proc/version

You may also be able to execute:
$ lsb_release -id

If your version of Linux is not listed in the above list, then you don’t have a certified version of Linux installed.  You will have to get a certified version installed on the server, before you install the Oracle database server.  Please don’t try to install on uncertified Linux versions, because it may or may not install, but you are likely to sit with problems, that you may not be able to resolve.  One of the first questions that Oracle support will ask you, when you develop serious problems is; what version of Linux you are running the Oracle software on.  To have to change your version of Linux down the line, will be quite an exercise, as compared to doing it before you install the Oracle database.  Don’t be fooled by articles that you will find on Google with claims that they have installed Oracle on Ubuntu etc, and are running production systems with no side effects.  Be very careful of these scenarios, because potentially the only remedy may be a rebuild.

Franz Devantier,
Need a database health check?

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Tuesday, July 23, 2013

Oracle Database Preinstallation – Part 2



Dear Readers,

My name is Franz Devantier, creator of this blog.  I am an Oracle Certified Professional (OCP DBA 11g) Security DBA.  I will be sharing with you the basic duties of an Oracle DBA, and also some of the undocumented, and not so well known tasks. 


I will make a deal with you:  If you refer me to a company that needs database support, from a few hours per week to full time, and I am able to sign a contract with them.
Then I will give you 10% of the monthly contract or deal price every month.  When the contract ends, and we re-sign the contract, I will again give you 10% of the monthly contract price.  This will go on until the company no longer employs or contracts me or my agents to look after their databases.
I can do this, because that 10% is my marketing budget.  When we re-sign the contract, in the future, it may depend on you giving the thumbs up again, and that is worth 10% of the monthly contract price, to be given to you as commission.
Contact: Franz

Oracle Database Preinstallation – Part 2
System Architecture
Here we are just going to verify that the system architecture can run the software.
$ uname –m
Now you need to crosscheck with the Oracle documentation, being especially careful with regards to versions.  If things do not match up exactly here, then you will not be able to have a successful install.  Typically you will need to give these findings back to business or management.

Disk Space Requirements
Below are the minimal requirements for installing the Oracle database 11.2.
=> 1GB of space in the /tmp directory
$ df –h /tmp
If there is not enough space, then you need to address this issue, before continuing.  You can address this issue by deleting unnecessary files form the /tmp directory.  You may consider resizing the /tmp directory.  When you configure Oracle, make sure that you set the TMP and TMPDIR environment variables to appropriate values.

Depending on the installation type, there would be different space requirements, for example:
Installation Type
Requirements for Software Files in GB
Enterprise edition
3.95
Standard Edition
3.88
Installation Type
Disk Space for Data Files in GB
Enterprise edition
1.7
Standard Edition
1.5
Installation Type
Requirements for Software Files in GB
Enterprise edition
4.35
Standard Edition
4.22
Installation Type
Disk Space for Data Files in GB
Enterprise edition
1.7
Standard Edition
1.5


The bottom half is the specific requirements for Linux x86-64.  Each OS will have slightly different requirements.

Before you start the installation you should determine the amount of free space on the system.
$ df –h

Don’t forget that additional free disk space is required on your file system or ASM disk group, if you are using the fast recovery area, and automated backups.  Make sure that you have enough space for this configuration, because otherwise the system can potentially hang when it runs out of space.  It is designed to hang, so that the integrity of the data is protected, rather than availability by default.  Think of it this way, not too much point in having things available if the data that you see has been corrupted or compromised.  Rather have too much space allocated for the fast recovery area to start with.

Display Requirements
The minimum resolution for Oracle Database 11.2 is quite high.  The tools will not work on a Display resolution of less than 1024 X 768.  Perhaps a good idea to make sure that you have a decent screen or monitor, before you even start your pre-installation checks.

Franz Devantier,
Need a database health check?
devantierf@gmail.com

Classifieds


Monday, July 22, 2013

Oracle Database Preinstallation – Part 1

Dear Readers,

My name is Franz Devantier, creator of this blog.  I am an Oracle Certified Professional (OCP DBA 11g) Security DBA.  I will be sharing with you the basic duties of an Oracle DBA, and also some of the undocumented, and not so well known tasks. 


I will make a deal with you:  If you refer me to a company that needs database support, from a few hours per week to full time, and I am able to sign a contract with them.
Then I will give you 10% of the monthly contract or deal price every month.  When the contract ends, and we re-sign the contract, I will again give you 10% of the monthly contract price.  This will go on until the company no longer employs or contracts me or my agents to look after their databases.
I can do this, because that 10% is my marketing budget.  When we re-sign the contract, in the future, it may depend on you giving the thumbs up again, and that is worth 10% of the monthly contract price, to be given to you as commission.
Contact: Franz

Oracle Database Preinstallation – Part 1
These are the tasks that you must complete, before you run Oracle Universal Installer (OUI).
Generally speaking there are two things that you should do before installing the Oracle software.  Firstly you should download the installation manual for your specific manual, and perform the pre-installation tasks.  Secondly if you are going to use Oracle Automatic Storage Management (ASM), or Oracle restart, then you should start off by installing Oracle Grid Infrastructure.

My notes are relevant to Linux and Unix, because with windows, most of these pre-installation tasks are transparent, and you can usually just get away with, putting the installation disk in and running it.  Actually I will be focussing on Linux, because Oracle has invested a lot into Linux, and secondly it is very convenient to load the Linux operating system onto your laptop or workstation, or virtual OS.  Oracle Linux has a free version, which you can download and install.  So we are looking at Oracle linux really, which is essentially Red Hat.   

Logging in to the System as root
Firstly you need to complete several tasks as the root user.  If the organization has a problem with giving the DBA the root password, then you will need to work very closely with the Sys Admin.  In windows you really just need an administrator login, and you are good to go.

You must install the software using a X Windows utility, or a X terminal, or any other system that can use or invoke X Server software.  If you are using silent mode installation, the you don’t need X Windows.

Installing from X Windows workstation or X Terminal:
=> Firstly you need to start your local terminal session, which could be something like “xterm”.

=> If you are not going to install the software on the local system, then you need to enable the remote host to display X applications on your local X Server or workstation.
You can achieve this something like:
$ xhost <fully qualified host name>

=> If you are going to install the software on the remote system, then use ssh, rlogin or telnet to connect to the system on which you want to install the software.  If you can use telnet on your site, then you have inherent issues, and I would suggest that you get an Oracle security expert to advice you.

=> If you are not logged in as root, then you must first do something like:
$sudo su root
Otherwise you must work closely with the companies sys admin.

=> To install the Oracle software on Linux, you may have to read through the specific X server documentation or request support from the specific vendors.  However the process should run something like this:
1.) Start your X server software
2.) Configure your X server to allow remote hosts to display X application on your workstation or local system.
3.) Connect to the remote server or where you want to install the Oracle software, and start your terminal or X windows session on that server.  For example an xterm session.  You may need to first logon to root, or do a “sudo” or “sudo su” to root, before you can proceed.

Now that you are logged onto the server where you will install the software, and have some sort of X Windows facilities, you are ready to verify the Hardware Requirements for the installation.

Verifying the Hardware Requirements for 11.2
We will check that we meet the minimal requirements.  If there has been time for planning, then you may have a set of hardware requirements that exceed the minimal requirements.  The areas that we will check include the Memory requirements, System architecture, Disk space requirements, and Display requirements.

Memory Requirements:
Minimum 1GB of RAM, recommended at least 2GB of RAM.

One way to determine the size of the RAM on a linux box is:
$ grep MemTotal /proc/meminfo
If the size of the RAM is less than the minimal required size, then you must first install more RAM before continuing.  The installation will abend if you try to install without enough RAM.

You also need to take into account the relationship between installed RAM, and the configured swap space.  There are specific recommendations by Oracle, and it is good to try to stay within those parameters.
RAM
Swap Space
Between 1GB and 2GB
1.5 times the size of the RAM, 1.5GB to 3GB
Between 2GB and 16GB
Swap space should be equal to the size of the RAM
More than 16GB
Swap space should not be larger than 16GB

If Oracle does start using too much swap space, during operations, you could have a drastically reduced performance throughput.  On Linux you can enable the HugePages feature.  HugePages are basically used for memory-mapped files.  If you are using HugePages, then you should deduct the memory allocated to HugePages from your RAM, before calculating the relationship between RAM and swap space.  You also need to verify that after deducting your HugePages from RAM, you still have at least 1GB of RAM left.

On linux you can use a command like this to verify the available RAM and swap space.
$ free

Remember that as the interactions with the server change, from busy to quite, your available RAM and swap space readings are going to keep changing; so you will need to perform this step under various stress conditions, to arrive at meaningful values.  It may also be useful to get recommendations from you OS vendor for specific guidelines on the RAM Swap space settings.

Using Automatic Memory Management (AMM)
From 11g onwards, AMM requires more shared memory than before, which on linux is defined in “/dev/shm”, as well as using more file descriptors.  Two parameters in the database must be smaller than the size of the defined shared memory.  MEMORY_MAX_TARGET or MEMORY_TARGET, typically MEMORY_MAX_TARGET would have the larger value, or would be equal to MEMORY_TARGET.  You would need to add values from all the Oracle instances on the computer, to properly determine the size to assign to the shared memory.

On Linux especially if the operating system mount size that has been defined is too small for the instance being started, defined in “/dev/shm”, then you will get the ORA-00845 error, when you try to start the instance.  The above mentioned Oracle memory variables, define the total size of the combined System Global Area (SGA), and Program Global Area (PGA).

The other variable that can bite is the file descriptors.  There should be at least 512 times the Oracle variable PROCESSES defined.  If the file descriptors is not sized correctly then you will get an Oracle error: ORA-27123.  Potentially you may also get the Linux error “EMFILE (Too many open files)”, especially with regards to non-Oracle related processes.

It is quite easy to determine the amount of shared memory available.
$ df –h /dev/shm/

Keep in mind that if you use the parameter LOCK_SGA, then you can’t use MEMORY_MAX_TARGET or MEMORY_TARGET.  Also if you have defined HugePages on the Linux level, then you can’t use MEMORY_MAX_TARGET or MEMORY_TARGET.

For example, if the shared memory file system allocation on your server is 1GB, and you have set MEMORY_MAX_TARGET = to 2GB, then you will get the following errors, when you try to start the database up.
ORA-00845    MEMORY_MAX_TARGET not supported on this system
ORA-01078   Failure in processing system parameters

To address the ORA-00845 error, you can increase the “/dev/shm” mountpoint size.
For example:
$ mount –t tmpfs shmfs -0 size=7g /dev/shm

Then you will need to make this change persistent across system restarts, by adding an entry in the “/etc/fstab”
For example:
$ smfs /dev/shm tmpfs size=7g 0


The database name is typically limited to 8 characters, however sometimes a user will have a requirement for the database to be named to something that is longer than 8 characters.  What happens in this situation is:
Let’s say the Global Database Name is longer than 8 characters.
DB_NAME parameter is truncated to 8 characters.
DB_UNIQUE_NAME parameter is set to the global name.
The end result is that this is fairly transparent to the end user, but remember the internal representation, for just in case you start to experience issues.

Franz Devantier,
Need a database health check?
devantierf@gmail.com

Classifieds