Oracle Database Administration for Microsoft SQL Server DBAs part 8 pdf

Disk Storage You will need storage for datafiles and log files, as well as disk space for installing the software, but what other disk storage is required?. You will need space for serve

to check that the oracle user has been added and to verify permissions You can edit the files with the vi editor or another text editor

> cat /etc/security/limits.conf

#<domain> <type> <item> <value>

#

# End of file

> cat /etc/pam.d/login

#%PAM-1.0

auth [user_unknown=ignore success=ok ignore=ignore default=bad] pam_security.so

# pam_selinux.so close should be the first session rule

session required pam_selinux.so close

# pam_selinux.so open should only be followed by sessions to be executed in the user context

session required pam_selinux.so open

session optional pam_keyinit.so force revoke session required /lib/security/pam-limits.so

Some system areas, such as those listed for the parameter and option settings, can normally be viewed but not modified Administrator permissions (root access) might be needed to make changes to these files If sharing the server with another application, it’s important to make sure that changes to these system areas are communicated, or discussed first Even without write permissions, having access to this information is helpful for doing a comparison

of what is needed and being able to communicate what configuration changes are needed to the server administrator

Other Linux Considerations

Filling up some shared areas, such as /tmp, will cause issues with running or installing Oracle software You should be careful about placing files in these areas and be sure to purge any old installation logs that are placed there

Required Packages

The Oracle installation guide lists the required packages for the various Linux flavors Some of the packages will already exist on your system, since they are included in the Linux installation You should verify that they were installed

by using the command rpm –q package_name You will need to install

any of the required packages that have not been installed by default

As an example, for Red Hat or Oracle Enterprise Linux 5.2 and Oracle

Database 11g Release 2 (R2), the following required packages are included in the Linux installation by default (verified by using rpm with the –q option):

binutils-2.17.50.0.6-6.el5 (x86_64)

compat-libstdc++-33-3.2.3-61 (x86_64)

compat-libstdc++33-3.2.3.61 (i386)

elfutils-libelf-9.125-3.el5 (x86_64)

glibc-2.5-24 (x86_64)

glibc-2.5-24 (i686)

glibc-common-2.5-24 (x86_64)

ksh-20060214-1.7 (x86_64)

libaio-0.3.106-3.2 (x86_64)

libaio-0.3.106-3.2 (i386)

libgcc-4.1.2-42.el5 (i386)

libgcc-4.1.2-42.el5 (x86_64)

libstdc++-4.1.2-42.el5 (x86_64)

libstdc++-4.1.2-42.el5 (i386)

make-3.81-3.el5 (x86_64)

If there are 32-bit and 64-bit versions listed, it doesn’t matter whether

you are running on a 32-bit or 64-bit version—both must be installed

Continuing with the same example, the following required packages are not installed by default and will need to be added:

elfutils-libelf-devel-0.125-3.el5.x86_64.rpm

elfutils-libelf-devel-static-0.125-3.el5.x86_64.rpm

elfutils-libelf-devel and elfutils-libelf-devel-static

static-0.125-3.el5.x86_64.rpm

glibc-headers-2.5-24.x86_64.rpm

kernel-headers-2.6.18-92.el5.x86_64.rpm

glibc-devel-2.5-24.x86_64.rpm

gcc-4.1.2-42.el5.x86_64.rpm

libgomp-4.1.2-42.el5.x86_64.rpm

libstdc++-devel-4.1.2-42.el5.x86_64.rpm

gcc-c++-4.1.2-42.el5.x86_64.rpm

libaio-devel-0.3.106-3.2.x86_64.rpm

libaio-devel-0.3.106-3.2.i386.rpm

sysstat-7.0.2-1.el5.x86_64.rpm

unixODBC-2.2.11-7.1.x86_64.rpm

unixODBC-2.2.11-7.1.i386.rpm

unixODBC-devel-2.2.11-7.1.x86_64.rpm

unixODBC-devel-2.2.11-7.1.i386.rpm

The first three packages listed need to be installed together:

> rpm -ivh elfutils-libelf-devel-0.125-3.el5.x86_64.rpm elfutils-libelf-devel

To install the unixODBC-devel-2 packages, enter the following at the Linux prompt:

>rpm –ivh unixODBC-devel-2*rpm

Once again, use rpm with the -q option to verify that a package is installed:

>rpm –q unixODBC-devel-2.2.11

The installation guide provided by Oracle will have the most up-to-date information for your versions of Oracle and Linux, and point out any

dependencies with certain packages and if there are any issues

Kernel Parameters

You may need to adjust the kernel parameters if your Oracle system will have high memory needs Recall from Chapter 2 the example of the error message that appears when the operating system doesn’t have enough memory to mount the /dev/shm file system Kernel parameters are in the /etc/sysctl.conf file, which can be edited to make the necessary modifications

kernel.shmall = physical RAM size / pagesize

kernel.shmmax = ½ of physical RAM, but < 4GB

kernel.shmmni =4096

kernel.sem = 250 32000 100 128

fs.file-max = 512 x processes

fs.aio-max-nr = 1048576

net.ipv4.ip_local_port_range = 9000 65500

net.core.rmem_default = 262144

net.core.mem_max = 4194304

net.core.wmem_default = 262144

net.core_wmem_max = 1048576

After this file is edited, you must activate the changes by running the

following at the command prompt as root:

sysctl –p

Use the following command to view the current settings for a kernel

parameter:

> /sbin/sysctl -a | grep <param-name>

This was a quick overview of the setup for the Linux operating system

The Oracle installation guide will have the details for your specific

environment

Storage Requirements

Now we need to look at where the database is going to live There are many storage options available with hardware, configurations, and file systems,

and with new hardware developments, even more options may be coming soon However, we do want to eventually get to actually installing Oracle,

so this will not be an all-inclusive discussion about storage, but enough to

cover the basics

If you don’t have enough memory in which to store the database—

whether it’s SQL Server or Oracle—fast read access is great For backing up data and applications that are heavy on the transactions, fast writing to the disk is another bonus In designing the storage layout, striping and mirroring play a definite part The databases need to be highly available, and the users will always be happier with faster access, so building in fault-tolerant systems

at the storage level is a necessity Making it fast is even better Chapter 10 will cover some I/O tuning and possible issues Here, we’ll first examine what disk storage is needed, and then look at Oracle Automatic Storage

Management (ASM), which can simplify your work by handling much of the storage for you We’ll also review the types of Oracle files

Disk Storage

You will need storage for datafiles and log files, as well as disk space for installing the software, but what other disk storage is required? You will need space for server logs and backups, and possibly a scratch area for exports and working with files

Although you could use certain storage solutions, such as striping, to make your database system work with just two disk drives or one file system, such a setup isn’t ideal With Linux, it’s possible to just have one mount point and place everything there under different directories To set up storage for a particular system properly, the DBA needs to understand the different pieces: files, I/O events, and backups You need to know which are typical events for databases and which are not, and which databases are heavy on read and writes of disk, and how each of these can affect the disk storage needed Under Windows, you would at least hope for two additional drives besides the C: drive For example, you might set up disk storage on

Windows as follows:

■ D:\oracle Base directory for software and server logs

■ D:\oradata For datafiles and one control file

■ E:\oradata Another location for control files

Control files contain information about the datafiles that can be used for recovery, as discussed in the “Oracle Files” section a little later in the chapter You should place the control files in different directories and have multiple copies available in case they are needed

Under Linux, you might set up your disk storage as follows (/u0n is a

typical naming convention):

■ /u01/oracle Base directory for software, server logs, and control files

■ /u02/oracle/SID For exports, archives, backups, and control files

■ /u03/oracle/SID For datafiles (numbers can continue to increase)

and control files

Alternatively, you could use another naming convention such as /ora0n, and this type of setup:

■ /ora01/oracle Base directory for software

■ /ora01/SID For datafiles and control files

■ /ora02 and subdirectories For export, backups, control files, and

so on

These are just some examples, intended to demonstrate how you might break up the software, datafiles, and backup files

Storage Management with ASM

ASM makes managing datafiles simple With Oracle Database 11g R2, ASM can manage all of the files—database files, nonstructured binary files, and

external files including text files

This means that all of the discussion in the previous section could

actually be ignored ASM handles managing the disk, adding disk storage,

and tuning I/O performance with rebalancing while the storage is up and

available to the Oracle databases on that server The discussion then just

comes down to how many disk groups you will create ASM will take care

of mirroring and striping Different levels of redundancy are available for the disk groups: normal, high, and external With external, ASM doesn’t provide the redundancy, but it can take advantage of external hardware mirroring

With Oracle Database 10g and even 11g R2, the ASM installation was part

of the database software installation routine Starting with Oracle Database 11g R2, ASM is a separate installation using the Grid Infrastructure Use a different home directory than the database home directory for the installation of ASM, and perform the installation as another user, such as asmadm user The home directory for ASM contains other pieces, such as Clusterware, which are part

of the ASM installation

If you are installing a version of Oracle earlier than 11g R2, start the installation process of the database software After you set the home to install the software, an option will come up for choosing which type of install to

do, as shown in Figure 3-2

FIGURE 3-2. Choose to install ASM in Oracle Database 11g R1 or earlier

versions

After you choose the ASM installation, the Database Configuration

Assistant will start to create the instance that is used by ASM In Figure 3-3, the password is set for the system user, and the parameters to discover the

disk groups can be set here as well

Next, create the disk groups You can also add disk groups later You

should see a list of devices available for the disk groups; if not, the parameter for disk discovery might not be set Figure 3-4 shows how to set this discovery path, and then select the disks to be part of the disk group Here is where the redundancy for the disk group is selected This is just the setup of the ASM instance In Chapter 10, we will look at how this plays into a highly available database environment

If you are installing Oracle Database 11g R2, ASM is a Grid Infrastructure installation As shown in Figure 3-5, you can install Clusterware and the Grid Infrastructure With this installation, the creation of the ASM instance, disk groups, and volumes is done by the ASM Configuration Assistant instead of the Database Configuration Assistant

You can also use the ASM command-line utilities ASMCMD and ACFSUTIL

to create and manage the disks Here’s an example of creating a volume group from the operating system command line:

ASMCMD > volcreate -d DISKGRPDATA -s 20G volume1

ASMCMDcan help manage the instance, with startup and shutdown, disk group, and disk failure management

The setup of the ASM disks needs to be done before even installing ASM instance The disk groups can be created so that they are available for the

software install If using the file manager for the regular files, such as create scripts and parameter files, as well as the datafiles for the database, these

disks and storage areas will need to be available for installation

We have just scratched the surface of ASM It has many more features

and options, and is an important piece of a stable database environment

Oracle Files

Various types of files are part of the Oracle system Understanding what

these files contain will help you to plan for storage and disk space