Adding disk space to the Charon-PAR emulated guest systems systems is a process consisting of several steps:

• Build disk container files in the Linux host file system.

• Link these disk container files with the corresponding emulator configuration paths in the Charon configuration file.

• Enable the disk for use by the guest operating system.

• For Charon-PAR/PA3:

  • Define virtual disk devices using SYSGEN on MPE/iX.

  • Create the virtual volume using VOLUTIL on MPE/iX.

There is no direct correspondence between the number of virtual disks that are added to the emulated system and the number of Linux disks on which they reside. The storage on the host system just must provide enough capacity to store the disk containers used as virtual disks by the emulated system.

The sections below describe the process in more detail.

Please note that it is not recommended to place emulator storage devices (in particular vdisks) on NFS as this will have a significant impact on performance. However, if any of the storage (e.g., ISO files or vdisks) is on an NFS share, NFS locking must be enabled and all intermediate firewalls between client and server must allow the port used by the lockd and statd. Failure to do so will cause the emulator to hang at startup.

The disk container files are created using the dd command. This command takes an input file name, an output file name, a block size, and a count as parameters. When instructed to read from /dev/zero , the command creates the output file and fills it with (block-size * count) zero bytes. Each file may be built as large as needed.

Please note: The maximum disk size supported by MPE/iX is 512GB. The maximum size for HP-UX is 2TB.

Use the following steps to create a new disk container file:

The new virtual disk must be added to the configuration file of the Charon-PAR instance. This requires two commands:

The device name DKXnnn encodes the device type and the device path of the emulated SCSI device presented to the guest operating system:

A disk device name has the following components:

• Value DK at the beginning of the device name: specifies that device type is disk.

• X: value consists of an uppercase letter encoding the device path. Please refer to Emulated Model Hardware Configuration Details and the relevant configuration file templates for system specific device path information.
  Example (rp4000):
  A = device path 0/0/1/0
  B = device path 0/0/1/1
  C = device path 0/0/2/0
  D = device path 0/0/2/1

• nnn: value encodes the SCSI device connected to the SCSI controller.
  Formula: (SCSI target ID*100)+LUN

The following example adds a SCSI disk with device path 0/0/1/0.0.0 to the configuration:

Before the disk can be used by guest operating system applications, there are some required steps that need to be performed on the guest OS. The following examples are only used for illustrative purposes. They are intended to provide a general impression of the necessary actions.

After booting the emulated system with the new disk added to the configuration file, check if HP-UX did recognize it:

Command	Example

Command	Example
To list all known disks on the system, enter the following command: # ioscan -C disk	The disk with device path 0/0/1/0.2.0 (DKA200) is the new disk: Open

During HP-UX boot-up, /sbin/insf is executed to create the character and block device special /dev files that allow communication with the disk. HP-UX uses the following device file naming system. For each disk device, the following special files are created:

• Block device file:
  /dev/dsk/c<number-of-card>t<SCSI-target-ID>d<device-LUN>

• Character device file:
  /dev/rdsk/c<number-of-card>t<SCSI-target-ID>d<device-LUN>

Where card is the (SCSI) controller number, target is the SCSI ID number, and device is the logical unit number, or LUN. The LUN is 0 for the majority of devices. An example for a disk at controller 0, target 2, LUN 0, is /dev/dsk/c0t2d0.