Hardware Planning

Hardware planning requires examining the physical hardware itself. One useful procedure is to sketch the hardware configuration in a diagram that shows adapter cards and buses, cabling, disks and peripherals. A sample diagram for a two-node cluster with a disk array is shown in Figure 4-1 “Sample Cluster Configuration ”.

Figure 4-1 Sample Cluster Configuration

Create a similar sketch for your own cluster, and record the information on the Hardware Worksheet. Indicate which device adapters occupy which slots, and calculate the bus address for each adapter. Update the details as you do the actual configuration (described in the chapters "Building an OPS Cluster Configuration" and "Configuring Packages and Their Services").




	NOTE: The process of configuring a cluster is easier if nodes as far as possible have identical hardware configuration (for example, interface cards on different nodes have the same hardware I/O path, and a given disk on a shared bus has the same device file name on different nodes.)

In addition to creating a diagram like the one described above, be sure to record the characteristics of the hardware on the Hardware Worksheet. Use one form for each SPU. The form has three parts:

SPU Information
Network Information
Disk I/O Information

SPU Information

All HP 9000 Series 800 SPUs are supported by ServiceGuard OPS Edition and different models can be mixed in the same cluster. This includes both uniprocessor and multiprocessor computers. HP 9000 Series 700 SPUs are not supported by ServiceGuard OPS Edition.

SPU information includes the basic characteristics of the S800 systems you are using in the cluster. On the worksheet, include the following items:

S800 Series Number

Enter the series number, such as, T600.

Host Name

Enter the name to be used on the system as the host name.

Memory Capacity

Enter the memory in MB.

Number of I/O slots

Indicate the number of slots.

NFS diskless clusters and NetLS servers are not supported.

Network Information

ServiceGuard monitors LAN interfaces as well as configured serial (RS232) lines.

LAN Information

While a minimum of one LAN interface per subnet is required, at least two LAN interfaces, one primary and one or more standby, are needed to eliminate single points of network failure.

It is recommended that you configure heartbeats on all subnets, including those to be used for client data. On the worksheet, enter the following for each LAN interface:

Subnet Name

Enter the IP address mask for the subnet. Note that heartbeat IP addresses must be on the same subnet on each node.

Interface Name

Enter the name of the LAN card as used by this node to access the subnet. This name is shown by lanscan after you install the card.

IP Address

Enter this node's host IP address intended to be used on this interface. The IP address is a string of digits separated with periods in the form nnn.nnn.nnn.nnn. If the interface is a standby, enter Standby.

Kind of LAN Traffic

Identify the purpose of the subnet. Valid types include the following:

Heartbeat
Client Traffic
Standby

Label the list to show the subnets that belong to a bridged net.

Information from this section of the worksheet is used in creating the subnet groupings and identifying the IP addresses in the configuration steps for the cluster manager, distributed lock manager, and package manager.

RS232 Information

If you plan to configure a serial line (RS232), you need to determine the serial device file that corresponds with the serial port on each node.

If you are using a MUX panel, make a note of the system slot number that corresponds to the MUX and also note the port number that appears next to the selected port on the panel.
On each node, use ioscan -fnC tty to display hardware addresses and device file names. For example:
# ioscan -fnC tty
This lists all the device files associated with each RS232 device on a specific node.
Once you have identified the device files, verify your connection as follows. Assume that node 1 uses /dev/tty0p0, and node 2 uses /dev/tty0p6.
- From a terminal on node 1, issue the following command:
  # cat < /dev/tty0p0
- From a terminal on node 2, issue the following command:
  # cat /etc/passwd > /dev/tty0p6
  The contents of the password file should be displayed on the terminal on node 1.
On the worksheet, enter the following:

Node Name

Name of the node.

RS232 Device File

Enter the device file name corresponding to a serial interface on each node.

Setting SCSI Addresses for the Largest Expected Cluster Size

SCSI standards define priority according to SCSI address. To prevent controller starvation on the SPU, the SCSI interface cards must be configured at the highest priorities. Therefore, when configuring a highly available cluster, you should give nodes the highest priority SCSI addresses, and give disks addresses of lesser priority.

For Fast/Wide SCSI, high priority starts at seven, goes down to zero, and then goes from 15 to eight. Therefore, seven is the highest priority and eight is the lowest priority. For example, if there will be a maximum of four nodes in the cluster, and all four systems will share a string of disks, then the SCSI address must be uniquely set on the interface cards in all four systems, and must be high priority addresses. So the addressing for the systems and disks would be as follows:

Table 4-1 Fast/Wide SCSI Addressing in Cluster Configuration

System or Disk	Host Interface SCSI Address
Primary System A	7
Primary System B	6
Primary System C	5
Primary System D	4
Disk #1	3
Disk #2	2
Disk #3	1
Disk #4	0
Disk #5	15
Disk #6	14
Others	13 - 8




	NOTE: When a boot/root disk is configured with a low-priority address on a shared SCSI bus, a system panic can occur if there is a timeout on accessing the boot/root device. This can happen in a cluster when many nodes and many disks are configured on the same bus. The correct approach is to assign SCSI addresses in such a way that the interface cards on cluster nodes have the highest priority SCSI addresses, followed by any boot/root disks that are on the shared bus, followed by all other disks on the shared bus.

Disk I/O Information

This part of the worksheet lets you indicate where disk device adapters are installed. Enter the following items on the worksheet for each disk connected to each disk device adapter on the node:

Bus Type

Indicate the type of bus. Supported busses are FibreChannel, single-ended SCSI, and F/W SCSI.

Slot Number

Indicate the slot number in which the interface card is inserted in the backplane of the computer.

Address

Enter the bus hardware path number, which will be seen on the system later when you use ioscan to display hardware.

Disk Device File

Enter the disk device file name. To display the name use the ioscan -fnC disk command,

Information from this section of the worksheet is used in creating the mirrored disk configuration using Logical Volume Manager. In addition, it is useful to gather as much information as possible about your disk configuration. You can obtain information about the I/O configuration by using the following commands:

diskinfo
ioscan -fnC disk
lssf /dev/dsk/c*
bdf
mount
swapinfo
vgdisplay -v
lvdisplay -v
lvlnboot -v
vxdg list (VxVM and CVM)
vxprint (VxVM and CVM)

These are standard HP-UX commands. See their man pages for information of specific usage. The commands should be issued from all nodes after installing the hardware and rebooting the system. The information will be useful when doing LVM and cluster configuration. A printed listing of the output from the lssf command can be marked up to indicate which physical volume group a disk should be assigned to.

Hardware Configuration Worksheet

The following worksheet will help you organize and record your specific cluster hardware configuration. Make as many copies as you need. Complete the worksheet and keep it for future reference.

Figure 4-2 Hardware Configuration Worksheet

    SPU Information:
 
    S800 Host Name ____ftsys9___________    S800 Series No ______892____________
 
    Memory Capacity ____128 MB _________    Number of I/O Slots ______12_______
    =============================================================================
    LAN Information:
 
    Name of           Name of              Node IP              Traffic
    Subnet __Blue___  Interface ___lan0___ Addr___35.12.16.10__ Type   ____HB___
 
    Name of           Name of              Node IP              Traffic
    Subnet __Blue___  Interface ___lan2___ Addr_______________  Type   _standby_
 
    Name of           Name of              Node IP              Traffic
    Subnet __Red____  Interface ___lan1___ Addr___35.12.15.12_  Type _HB, client
    =============================================================================
    Serial (RS232) Heartbeat Interface Information:
 
    RS232 Device File ___/dev/tty0p0__
 
    Second Node Name ____ftsys10__________
 
===============================================================================
    X.25 Information
 
    OTS subnet  ____________________ OTS subnet  ____________________
    =============================================================================
    Disk I/O Information for Shared Disks:
 
    Bus Type _SCSI_ Slot Number _4__ Address _16_ Disk Device File __c0t1d0_
 
    Bus Type _SCSI_ Slot Number _6_  Address _24_ Disk Device File __c0t2d0_
 
    Bus Type ______ Slot Number ___  Address ____ Disk Device File  _________
 
    Attach a printout of the output from the ioscan -fnC disk command
    after installing disk hardware and rebooting the system.  Mark this
   printout to indicate which physical volume group each disk belongs to.