IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning

270 IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning

Following, we provide a short description of the different run levels used in Linux:

– 0 - Halt (do not set initdefault to this or the server will immediately shut down after

finishing the boot process).

– 1 - Single user mode.

– 2 - Multi-user, without NFS (the same as 3, if you do not have networking).

– 3 - Full multi-user mode non-graphical.

– 4 - Unused.

– 5 - Full multi-user mode graphical X11.

– 6 - Reboot (do not set initdefault to this or the server machine will continuously reboot

at startup).

3. To prevent a daemon from starting, you will need to rename the appropriate file in the \etc

directory structure. For example, to disable the sendmail daemon in run level 3 at startup,

enter the command:

rename /etc/rc3.d/S80sendmail /etc/rc3.d/K80sendmail

Or,

mv /etc/rc3.d/S80sendmail /etc/rc3.d/K80sendmail

Daemons with an S at the beginning of the symbolic link name will be started; those

starting with a K will not be started in that specific run level. In our example, the sendmail

daemon will not be started on the next reboot. Note that you must select the correct run

level to change this.

8.2.4 Compiling the kernel

Compiling the kernel is not absolutely necessary to improve the performance of the server,

but we do recommend that you configure your Linux server to have the latest DS6000

supported kernel and drivers. There are always new improvements being made available,

which not only fix bugs, but also improve the performance of the Linux machine.

Before you begin, you will need to know what hardware is installed in the server. You can

obtain a list by typing in the command lspci. The most important things to know are:

򐂰 CPU type

򐂰 Amount of memory installed

򐂰 SCSI adapter

򐂰 RAID controller

򐂰 Fibre Channel adapter

򐂰 Network adapter

򐂰 Video adapter

The more information you have about the hardware used, the more easily the Linux kernel

can be configured.

This procedure can be tricky at some steps, so we refer you to a complete discussion of how

to compile the kernel in the IBM Redpaper, Running the Linux 2.4 Kernel on IBM Eserver

xSeries Servers, REDP0121, available from:

http://www.redbooks.ibm.com

Select Redpapers from the left navigation bar and do a search using the Redpaper form

number REDP0121.