Pre-installation tasks

WARNING! If you install Adaptive Server for an upgrade, you cannot install it into the same directory as the currently installed version. The new version overwrites the old one, causing the upgrade to fail. You must have both the old and the new versions of Adaptive Server to perform an upgrade.

Table 4-1 is a list of the environment variables and their default settings.

**Table 4-1: Environment variables**
Variable	Set to...
$SYBASE	The installation directory. By default /usr/sybase
$SYBASE_ASE	ASE-12_5
$SYBASE_OCS	OCS-12_5
$SYBASE_SYSAM	SYSAM-1_0
$DISPLAY You must manually set the $DISPLAY environment variable.	your_display:0.0 where your_display is the name of your machine. This variable must be set when performing a remote installation.

Table 4-1: Environment variables

Variable

Set to...

$SYBASE

The installation directory. By default /usr/sybase

$SYBASE_ASE

ASE-12_5

$SYBASE_OCS

OCS-12_5

$SYBASE_SYSAM

SYSAM-1_0

$DISPLAY

You must manually set the $DISPLAY environment variable.

your_display:0.0 where your_display is the name of your machine. This variable must be set when performing a remote installation.

Before installing Sybase servers:

Read the release bulletins for the latest information on the products (Adaptive Server, Monitor Server, and so on) that you are installing. See the “Special Installation Instructions” section in the release bulletin.

Install operating system patches, if required. Required operating system patches are described in the release bulletin for the product.

Your Sybase product shipment includes printed release bulletins; they are also availablehttp://www.sybase.com/support/manuals.

Review the SySAM procedures and plan your client/server configuration using Chapter 3, “Sybase Software Asset Management (SySAM).”

Create a “sybase” account on your system to perform all installation tasks.

The “sybase” user must have permission privileges from the top (or root) of the disk partition or operating system directory down to the specific physical device or operating system file.

Add /usr/bsd to your path.

It is important to maintain consistent ownership and privileges for all files and directories. A single user—the Sybase System Administrator with read, write, and execute permissions—should perform all installation, upgrade, and setup tasks.

Identify or create a directory location for the Sybase installation directory, where you install the server products.

If you are installing for an upgrade, see Chapter 8, “Upgrading Sybase Servers.”

Verify that:

The directory location for the Sybase installation has sufficient space. Include an additional 2.4MB space for the installation program.
Your operating system meets the version-level, RAM, and network-protocol requirements.
The installation directory does not have a space in the directory name. For example, installing Sybase products into the directory Program Files results in unpredictable behavior.
The sybsystemdb database is required to support distributed transaction management (DTM) features. Before installation, make sure you have enough space available on the default segment to support sybsystemdb. See Chapter 2, “Installation Requirements.”

Space requirements for Adaptive Server Enterprise products are listed in Chapter 2, “Installation Requirements.”

If you are performing an installation on a remote machine, set the DISPLAY variable of the local X11 server.

On the local machine where you are monitoring the installation of Adaptive Server, enter:
```
% setenv DISPLAY remote_display:0.0
```
where remote_display is the name of the machine on to which you are installing the software.
On remote machine where you are installing Adaptive Server, enter:
```
$ xhost +
```

Verify that your network software is configured.

Sybase software uses network software even if Adaptive Server and Sybase client applications are installed on a machine that is not connected to a network.

If you are having connection problems, or if you want to verify your network configuration, complete these steps:

Log in to your host machine with this UNIX command:
```
    telnet host
```
This command gives you a login prompt for the same machine.
Without logging out, log in to your host machine a second time, using the same command.

If you cannot log in to the machine a second time, your network software is not properly configured to run in loopback mode. See the network software documentation, or consult your vendor.
Log out twice.

Adjust the operating system shared memory parameter, if necessary.

For Adaptive Server to run, the operating system must allow allocation of a shared memory segment at least as large as the Adaptive Server total logical memory configuration parameter.

The default size limit for shared-memory segments on IRIX 6.5 is 80 percent of physical memory, which should be sufficient. To verify the current setting use the command:

systune shmmax

To adjust the setting, log in as “root”, and use the command:

systune shmmax nnn

where nnn is at least 28MB for a default Adaptive Server.

After you install Adaptive Server, you can change any configuration parameter, procedure cache, and data cache. This may also require you to increase the configuration parameter max memory.

Adjust shared memory segments.

Depending on the number and types of devices you use for backup (dump) and recovery (load), you may need to adjust the shared memory segment parameter in the operating system configuration file to accommodate concurrent Backup Server processes. The default number of shared memory segments available for process attachments is 2000. To determine whether the limit has been configured differently, use the command:

systune sshmseg

Adaptive Server may allocate shared memory segments after start-up if any reconfiguration through sp_configure requires additional memory. You may need to account for these additional segments. This can be avoided by allocating all the shared memory during the start-up, for the maximum memory you will make available to Adaptive Server, by using the allocate max shared memory configuration parameter. See the System Administration Guide for more information.

SGI has two methods of executing asynchronous I/O:

For asynchronous I/O Adaptive Server uses the functions found in libC.so. Customers enable asynchronous I/O by turning on the allow sql server asynchronous i/o flag in the .cfg file. This is commonly known as uaio.

Prior to Adaptive Server 12.5, uaio used sproc()s. These were visible in the ps -elf listing.

In Adaptive Server version 12.5 the asynchronous I/O functions now use pthreads rather than sproc()s; you no longer see the extra pocesses. The ps -T command shows the pthreads.

Uaio functions are configurable using the environment variable AIO_THREADS to designate the number of pthreads per engine. The AIO_THREADS environment variable is set by the System Administrator.

Uaio is implemented through POSIX threads (pthreads). Dataserver engines create the pthreads at start-up. These pthreads run in user space and interact with the operating system AIO library in kernel space.

Although each engine can queue many I/O operations, the I/O requests are passed one at a time to the AIO library by each pthread. Increase I/O parallelism by increasing the number of pthreads.

The value of AIO_THREADS depends on the number of database devices and the number of CPUs on the system.

The default value for AIO_THREADS is 5. Although there is no maximum limit, Sybase recommends that you do not set AIO_THREADS to more than 75 per engine. As a general rule, there should be 1 pthread per 1.5 drives. For example, for a machine with 10 drives, set AIO_THREADS to 15.

The number of processes for the AIO_THREADS environment variable is n+2 for each engine running, where n is the value of AIO_THREADS. For example, if AIO_THREADS is set to 5, the number of processes is 7. If two engines are running, the number of processes is 14.

You must restart Adaptive Server for this environment variable to take effect.
The SGI Database Accelerator package (DBA) moves asynchronous I/O from user-space into kernel space (commonly called KAIO). If you elect to use KAIO, you must install DBA (version 3.0 or higher) and set an environment variable in the server start-up script.

KAIO only applies to raw (character special) devices, but coexists with file system asynchronous I/O. Databases located on file system devices use uaio, while raw devices use KAIO.

To confirm that KAIO is in use issue ps -T. (Make sure that no file system devices are being used, because file system device use causes pthreads to display in the ps -T listing.)

Another way to confirm that KAIO is in use is to issue the command par -i -n syssgi on the running dataserver. If SGI_KAIO_READ or SGI_KAIO_WRITE display, then KAIO is active.

It is recommended that all devices be raw unless there is heavy use of tempdb. If there is heavy tempdb use, you should elect to use cooked devices for the buffering. You can also create an xlv and not build a file system so that KAIO can be used.In addition to setting the allow sql server async i/o flag to true in the .cfg file, the RUN_SERVER file should set the environment variable __SGI_USE_DBA to one indicating that KAIO is being used. The following is an example RUN_SERVER file:
```
#!/bin/sh
# set up kaio
__SGI_USE_DBA=1; 
export __SGI_USE_DBA
SYBASE=/usr/sybase
$SYBASE/bin/dataserver -d/dev/rdsk/dks0d6s1 \
-sSYBASE -e$SYBASE/install/errorlog_SYBASE \
-i$SYBASE
```

Determine the location, type, and size of each database device.

You must provide this information during the installation of Adaptive Server. Devices are operating system files or portions of a disk (called raw partitions) used to store databases and database objects. For details, see “Determining the location, type, and size of a database device”.