Digital PDFs

XX-9884D-B7

2000

11 pages

Original

74.7kB

Document:	AN-045
Order Number:	XX-9884D-B7
Revision:	0
Pages:	11
Original Filename:	AN-045.pdf

OCR Text

CHARON-VAX application note
AN-45 DSSI emulation in CHARON-VAX/XM/XK/XL for Windows
Author: Vadim Model

Date:

25-Feb-2007

Scope
These notes cover the implementation of the virtual DSSI storage subsystem for CHARONVAX/XM/XK/XL for Windows. For this field test, the DSSI emulation is implemented as
additional DLLs to be used with a CHARON-VAX product installation. The use of
VAX/VMS as operating system is assumed in these notes.
The DSSI storage subsystem for the VAX 4000 Models 106 and 108 emulators is based on
the emulation of SHAC host adapters and the ability to route SCS cluster information between
the emulated SHAC host adapters of multiple nodes via separate TCP/IP links.

Limitations
This first implementation was tested with CHARON-VAX/XL product version 1.1.51 and can
only be used on a 32 bits Windows host system. The DSSI storage subsystem is functionally
emulated, but physically incompatible with DSSI and operates at a much higher throughput
than the original hardware. Connection to physical DSSI hardware is neither possible nor
planned for future releases.
This version of DSSI emulation for CHARON-VAX/XL for Windows supports up to 3 VAX
nodes in a virtual DSSI cluster and handles a maximum cluster size of 8 nodes. A single
virtual DSSI network supports up to 256 storage elements.
Field test versions of DSSI emulation should not be used for production. DSSI functionality
can be removed from a production system that is temporary used for field test by simply
removing the DSSI components from the configuration file.

CHARON-VAX/XL DSSI configuration overview
To use a single CHARON-VAX/XL system with DSSI emulation, either or both of the two
elements must be configured:

A DSSI storage element (disk or tape).

A DSSI storage controller. In this field test version an emulated HSD50 storage
controller is provided. The emulated HSD50 supports physical host drives, CDRom
drives, physical tapes, removable disks, virtual disks and tapes.

To create a cluster of DSSI interconnected CHARON-VAX/XL systems, the DSSI hardware
topology is emulated by establishing TCP/IP channels between the emulated SHAC host
adapters of each CHARON-VAX/XL system (The use of TCP/IP for the interconnects makes
the cluster in principle routable in a WAN). The emulated HSD50 storage controllers are then
connected to every SHAC host adapter in the virtual DSSI network.
Cluster operation requires (virtual) disks that are simultaneously accessible by all CHARONVAX nodes involved. This can be implemented for instance by using a properly configured
iSCSI initiator / target structure or a fiber channel storage back-end. For test purposes
Windows remote shares can be used, but these do not offer the reliability required for a VAX
©2007 Software Resources International. This document is provided for information only and is not a legally binding offer.
Software Resources International reserves the right to change the product specifications without prior notice or retire the
product. The CHARON name and its logo are a registered trademark of Software Resources International.

CHARON-VAX application note
cluster. Disks on a multiport SCSI switch are not acceptable, as a SCSI switch does not
provides true simultaneous access to multiple nodes.
Note that the emulated DSSI subsystem has many configurable parameters when multiple
nodes on a single DSSI bus are to be configured. Incorrect configuration, in particular nonidentical specification of emulated HSD50 disks in the DSSI nodes are likely to case data
corruption. It is advisable to start any field test with implementing the single node and cluster
examples that are provided in these notes.

CHARON-VAX/XL DSSI configuration parameters
To connect an emulated VAX 4000 to a virtual DSSI network, the CHARON-VAX
configuration file must load at least one emulated CIXCD host adapter.
Note that VAX/VMS running on an emulated VAX 4000 node enumerates the emulated
SHAC host adapters, and assigns them the VMS internal names PAA and PAB. It is
recommended for clarity to keep the same naming scheme for emulated SHAC host adapters
in the CHARON-VAX configuration file. The two built-in SHAC host adapters are pre-loaded
with names PAA and PAB corresponding to VMS names.
The SHAC emulation has the following configuration parameters:
Parameter

Description

port[N]

An integer value that specifies the TCP/IP port number at which the
emulated SHAC host adapter listens for connections from another
emulated SHAC host adapter with DSSI address N.

N=0…7

Possible values are from 1024 through 32767.
Initially not set.
host[N]
N=0…7

A string value that specifies the TCP/IP host name (and optionally
the TCP/IP port number) to connect to another emulated SHAC host
adapter with DSSI address N.
The syntax for the string is “host-name[:port-no]”, with possible
values for port-no in the range from 1024 through 32767.
Initially not set.

scs_node_name[N]
N=0…7

A string value that specifies the SCSNODENAME of the emulated
storage element.
The string is up to 8 characters long. Possible characters are
uppercase letters A through Z , figures 0 through 9.
Initially set to an arbitrary value that is guaranteed to be unique
within the running emulated VAX 4000 node.

scs_system_id[N]
N=0…7

An integer value that specifies the SCSSYSTEMID of the emulated
storage element.
Initially set to an arbitrary value that is guaranteed to be unique
within the running emulated VAX 4000 node.

mscp_allocation_class
[N]

An integer value which specified the ALLOCLASS of the emulated
storage element.

N=0…7

Possible values are from 0 through 255.

Page 2 of 11

CHARON-VAX application note
Initially set to 0.
container[N]
N=0…7

A string value that specifies the container of the storage element
with DSSI node id N and MSCP unit number N. This storage
element might be either a (virtual) disk or tape. In VMS running on
an emulated VAX 4000 node, these storage elements appear as DSSI
disks (DIAN:) or DSSI (TF86) tapes (MIAN:).
Possible values of the parameter are strings in one of the following
forms:
1. “\\.\PhysicalDrive”X, where X is 0, 1, … for accessing nonremovable physical disk drives;
2. “\\.\CdRom”X, where X is 0, 1, … for accessing compact
disk drives (read-only);
3. “\\.\Tape”X, where X is 0, 1, … for accessing physical tape
drives;
4. “\\.\”L, where L is A, B, … for accessing removable disk
drives (floppies, some optical media, …);
5. [<path-name>”\”]<file-name>[“.vdisk”]
for
accessing
CHARON disk images, or CHARON virtual disks;
6. [<path-name>”\”]<file-name>[“.dsk”]
for
accessing
CHARON disk images, or CHARON virtual disks;
7. [<path-name>”\”]<file-name>“.vtape”
for
accessing
CHARON tape images, or CHARON virtual tapes;
8. [<path-name>”\”]<file-name>“.mtd”
for
accessing
CHARON tape images, or CHARON virtual tapes;
This parameter is initially not set, thus creating NO storage elements
on the bus with corresponding DSSI node id.

geometry[N]
N=0…7

This string value with a special format specifies the explicit
geometry of the disk storage element with DSSI node id N and
MSCP unit number N. This parameter is not applicable to tape
storage elements.
The string format is <X>”/”<Y>[“/”<Z>] where
•

X is number of sectors on track;

•

Y is number of tracks on cylinder;

•

Z (optional) is the number of cylinders on the unit. If
omitted, Z is calculated based on X, Y and the total
number of sectors on the unit that reflects the size of the
disk storage element;

If this parameter is not set, CHARON-VAX will configure the
geometry based on the most probable disk type.
These parameters can be specified in a SET command.

Page 3 of 11

CHARON-VAX application note
Connecting storage controller to a virtual DSSI network
To connect storage controller to virtual DSSI network, the CHARON-VAX configuration file
must load at least one emulated HSD50 storage controller. In most cases one emulated HSD50
storage controller per virtual DSSI network is enough.
When loading an instance of emulated HSD50 storage controller the CHARON-VAX
configuration file must supply a unique reference name for that instance. While this name is
only valid within the configuration file, it is recommended for clarity that the VMS
SCSNODENAME is used as instance name.
The line below loads an emulated HSD50 storage controller and assigns it the instance name
MYDISKS, and connects it to the primary built-in DSSI controller:
load HSD50 MYDISKS dssi_host=PAA

The HSD50 emulation has the following configuration parameters (as per CHARON
configuration file syntax, all integer values can be entered in Hex, Decimal or Octal form):
Parameter

Description

dssi_host_name

A string value which specifies the instance name of emulated
CIXCD host adapter serving the same virtual CI network.
If this value is not set, CHARON-VAX will try to locate the host
adapter automatically. This automatic lookup works only if the
CHARON-VAX configuration has exactly one instance of an
emulated CIXCD host adapter.

dssi_node_id

An integer value which specifies the address of an emulated HSD50
storage controller on the virtual DSSI network.
Possible values are from 0 through 7 (initially set to 0).

scs_node_name

A string value that specifies the SCSNODENAME of the emulated
HSD50 storage controller.
The string is up to 8 characters long. Possible characters are
uppercase letters A through Z , figures 0 through 9.
Initially set to the name of the emulated HSD50 controller.

scs_system_id

An integer value that specifies the SCSSYSTEMID of the emulated
HSD50 storage controller.
Initially set to an arbitrary value that is guaranteed to be unique
within the running emulated VAX 4000 node.

mscp_allocation_class

An integer value which specified the ALLOCLASS of the emulated
HSD50 storage controller.
Possible values are from 0 through 255 (initially set to 0).

container[N]
N=0…255

A string value that specifies the container of the storage element
with MSCP unit number N. This storage element might be either a
(virtual) disk or tape. In VMS running on an emulated VAX 4000
node, these storage elements appear as HSX00 disks (DUAN:) or
HST00 tapes (MUAN:).
Possible values of the parameter are strings in one of the following

Page 4 of 11

CHARON-VAX application note
forms:
9. “\\.\PhysicalDrive”X, where X is 0, 1, … for accessing nonremovable physical disk drives;
10. “\\.\CdRom”X, where X is 0, 1, … for accessing compact
disk drives (read-only);
11. “\\.\Tape”X, where X is 0, 1, … for accessing physical tape
drives;
12. “\\.\”L, where L is A, B, … for accessing removable disk
drives (floppies, some optical media, …);
13. [<path-name>”\”]<file-name>[“.vdisk”]
for
accessing
CHARON disk images, or CHARON virtual disks;
14. [<path-name>”\”]<file-name>[“.dsk”]
for
accessing
CHARON disk images, or CHARON virtual disks;
15. [<path-name>”\”]<file-name>“.vtape”
for
accessing
CHARON tape images, or CHARON virtual tapes;
16. [<path-name>”\”]<file-name>“.mtd”
for
accessing
CHARON tape images, or CHARON virtual tapes;
This parameter is initially not set, thus creating NO storage elements
on the controller.
geometry[N]
N=0…255

This string value with a special format specifies the explicit
geometry of the disk storage element with MSCP unit number N.
This parameter should not be used for tape storage elements.
The string format is <X>”/”<Y>[“/”<Z>] where
•

X is number of sectors on track;

•

Y is number of tracks on cylinder;

•

Z (optional) is the number of cylinders on the unit. If
omitted, Z is calculated based on X, Y and the total
number of sectors on the unit that reflects the size of the
disk storage element;

If this parameter is not set, CHARON-VAX will configure the
geometry based on the most probable disk type.
The following example configures an emulated HSD50 storage controller with a non-default
DSSI network address of 5:
load HSD50 YOURDISK dssi_host=PAA dssi_node_id=5

Configuration example 1.
One VAX system and 2 disks
The configuration file below creates an emulated VAX 4000 Model 108 node with two DSSI
disks.

Page 5 of 11

CHARON-VAX application note
set session hw_model="VAX_4000_Model_108"
set session log="example1.log"
set toy container=" example1.dat"
set rom container=" example1.rom"
load virtual_serial_line OPA0 port=10003 application="opa0.ht"

set PAA container[0]="C:\mydisks\dia0-rz24-vms-v6.2.vdisk"
set PAA container[1]="C:\mydisks\dia1-rz24-vms-v6.2.vdisk"

The emulated VAX 4000 can then boot VMS with the following command:
>>> BOOT DIA0

After logging into VMS, the “SHOW DEVICE” command displays the following:
$ sho dev d

Device

Error

Volume

Free

Name

Status

Count

Label

Blocks Count Cnt

20004200$DIA0:

Mounted

20004201$DIA1:

Online

DSSI01

32022

Trans Mnt

147

$ _

Configuration example 2.
One VAX, 2 disks, and a tape drive on a separate HSD50 controllers
The configuration file below emulates a VAX 4000 Model 108 node, one HSD50 storage
controller serving two disks and another instance of a HSD50 that serves a tape drive to the
VAX over a virtual DSSI:
set session hw_model="VAX_4000_Model_108"
set session log="example2.log"
set toy container="example2.dat"
set rom container="example2.rom"

load virtual_serial_line OPA0 port=10003 application="opa0.ht"

load HSD50 MYDISKS dssi_host=PAA dssi_node_id=1
set MYDISKS container[0]="C:\mydisks\dua0-rz24-vms-v6.2.vdisk"
set MYDISKS container[1]="C:\mydisks\dua1-rz24-vms-v6.2.vdisk"

load HSD50 MYTAPE dssi_host=PAA dssi_node_id=2
set MYTAPE container[3]="\\.\Tape0"

Page 6 of 11

CHARON-VAX application note
In this example we emulate two HSD50 instances. Since they are both connected to the same
virtual DSSI bus, we must assign them different DSSI node id values.
The emulated VAX 4000 Model 108 can then boot VMS with the following command:
>>> BOOT DUA0

After logging into VMS, the “SHOW DEVICE” command displays the following:
$ sho dev d

Device

Error

Volume

Free

Name

Status

Count

Label

Blocks Count Cnt

MYDISKS$DUA0:

Mounted

MYDISKS$DUA1:

Online

Device

Error

Name

Status

Count

MYTAPE$MUA3:

Online

DSSI01

Trans Mnt

31932

147

Volume

Free

Trans Mnt

Label

Blocks Count Cnt

$ sho dev m

$ _

Virtual DSSI cluster configurations for the VAX 4000 emulator
The hardware DSSI bus establishes private node-to-node communication channels between
any two DSSI nodes that are part of the same DSSI bus. In this context, the DSSI storage
controllers are also nodes like VAX computers, but are running special software.
The CHARON DSSI emulation replicates this structure by establishing TCP/IP channels
between each pair of emulated SHAC host adapters, and by connecting the emulated HSD50
storage controllers to every SHAC on the same virtual DSSI network.
Consider a pair of emulated VAX 4000 nodes: VAX_A and VAX_B running on host system
HOST_A and HOST_B respectively.
The two emulated VAX nodes have their own emulated SHAC host adapters interconnected
with the virtual DSSI bus. In order to communicate properly, these two adapters must have
different DSSI node id’s (DSSI_NODE_ID_A and DSSI_NODE_ID_B), which must be
explicitly specified in the corresponding VAX consoles.
Next, every emulated SHAC host adapter participating in the virtual DSSI cluster must be
able to communicate to every other emulated SHAC host adapter in the same virtual DSSI
cluster. Such communication is performed over TCP/IP links established between every two
emulated SHAC host adapters.
N ⋅ ( N − 1)
such links.
A virtual DSSI cluster consisting of N emulated VAX 4000 nodes has
2
Every end of such link is identified by the pair:
{<TCP/IP-HOST-NAME>,<TCP/IP-PORT-NO>}.
Hence, on HOST_A the CHARON-VAX configuration file describes connection to HOST_B
as follows:
set PAA port[DSSI_NODE_ID_B]=TCPIP_PORT_A_FOR_B
set PAA host[DSSI_NODE_ID_B]=”HOST_B:TCPIP_PORT_B_FOR_A”

Page 7 of 11

CHARON-VAX application note
And on HOST_B the CHARON-VAX configuration file describes connection to HOST_A as
follows:
set PAA port[DSSI_NODE_ID_A]=TCPIP_PORT_B_FOR_A
set PAA host[DSSI_NODE_ID_A]=”HOST_A:TCPIP_PORT_A_FOR_B”

Next, every emulated SHAC host adapter must also connect to all emulated storage
controllers on the same virtual DSSI bus. This is similar to the non-clustered configurations
described before, except for the MSCP allocation class:
The VAX Cluster architecture requires every VAX node participating in the cluster be
assigned the MSCP allocation class. The same requirement applies to DSSI storage
controllers, which are also nodes on the DSSI. Therefore, when configuring an instance of an
emulated HSD50 storage controller, the MSCP allocation class for that controller must be
supplied through the corresponding parameter. For example, the following line:
load HSD50 MYDISKS dssi_host=PAA dssi_node_id=5 mscp_allocation_class=5

assigns the MYDISKS emulated storage controller the MSCP allocation class 5.

Configuration example 3.
A dual node VAX cluster with 4 disks
To setup two emulated VAX 4000 Model 108 nodes, we need two host machines, preferably
running the same version of Windows. Assume that these host systems have Windows host
names CASTOR and POLLUX in the host TCP/IP network.
The following is the CHARON-VAX configuration file for the emulated VAX 4000 Model
108 node named VAX001 running on CASTOR:
set session hw_model="VAX_4000_Model_108"
set session log="vax001.log"
set toy container="vax001.dat"
set rom container="vax001.rom"

load virtual_serial_line OPA0 port=10003 application="opa0.ht"

set PAA port[2]=11012 host[2]=”pollux:11021”

load HSD50 OURDISKS dssi_host=PAA dssi_node_id=1
set OURDISKS scs_system_id=3238746238 mscp_allocation_class=1
set OURDISKS container[0]="H:\ourdisks\dua0-rz24-vms-v6.2.vdisk"
set OURDISKS container[1]="H:\ourdisks\dua1-rz24-vms-v6.2.vdisk"
set OURDISKS container[2]="H:\ourdisks\dua2-rz24-vms-v6.2.vdisk"
set OURDISKS container[3]="H:\ourdisks\dua3-rz24-vms-v6.2.vdisk"

Page 8 of 11

CHARON-VAX application note
And the following is the CHARON-VAX configuration file for the emulated VAX 4000
Model 108 node named VAX002 running on POLLUX:
set session hw_model="VAX_4000_Model_108"
set session log="vax002.log"
set toy container="vax002.dat"
set rom container="vax002.rom"

load virtual_serial_line OPA0 port=10003 application="opa0.ht"

set PAA port[1]=11021 host[1]=”castor:11012”

Note that in the both configuration files, the data related to the emulated HSD50 storage
controller OURDISKS must be identical. Not following this rule will very likely cause data
corruption on the (virtual) disks. In this respect note the explicit specification of
SCS_SYSTEM_ID for the storage controllers.
As mentioned earlier, CHARON-VAX loads an initial (default) value for the
SCS_SYSTEM_ID that is guaranteed to be unique within the running emulator. But with two
instances of the emulator these default values are likely to be different. Therefore, the
SCS_SYSTEM_ID value must be specified explicitly for both emulated HSD50 storage
controllers to obtain an identical value.
This example also assumes that drive “H” is a network share, so that all disk images are
accessible from both host machines.

Configuration example 4.
A triple node VAX cluster with multiple iSCSI disks
In this example we assume that all three host systems have a iSCSI initiator (for example the
Microsoft iSCSI initiator) and are connected to a common iSCSI server. The iSCSI disk
server provides 8 virtual disks with R/W access on all hosts. These disks are configured as
\\.\PhysicalDrive1 ... \\.\PhysicalDrive8 on each of the host machines.
Since the storage configuration must be identical on all three nodes, it is recommended to
describe the storage structure in separate configuration file (to be included in each CHARON
configuration file) and store it on a common Windows network share (H:):
load HSD50 DISKSET1 dssi_host=PAA dssi_node_id=1
set DISKSET1 scs_system_id=3238746238 mscp_allocation_class=1
set DISKSET1 container[1]="\\.\PhysicalDrive1"

Page 9 of 11

CHARON-VAX application note
set DISKSET1 container[2]="\\.\PhysicalDrive2"
set DISKSET1 container[3]="\\.\PhysicalDrive3"
set DISKSET1 container[4]="\\.\PhysicalDrive4"

load HSD50 DISKSET2 dssi_host=PAA dssi_node_id=2
set DISKSET2 scs_system_id=1256412654 mscp_allocation_class=2
set DISKSET2 container[5]="\\.\PhysicalDrive5"
set DISKSET2 container[6]="\\.\PhysicalDrive6"
set DISKSET2 container[7]="\\.\PhysicalDrive7"
set DISKSET2 container[8]="\\.\PhysicalDrive8"

The following is the CHARON-VAX configuration file for the emulated VAX 4000 Model
108 node named VAX001 running on HOST001:
set session hw_model="VAX_4000_Model_108"
set session log="vax001.log"
set toy container="vax001.dat"
set rom container="vax001.rom"

load virtual_serial_line OPA0 port=10003 application="opa0.ht"

set PAA port[2]=11012 host[2]=”host002:11021”
set PAA port[3]=11013 host[3]=”host003:11031”

include h:\ourdisks\disksets.cfg

The CHARON-VAX configuration file for the emulated VAX 4000 Model 108 node named
VAX002 running on HOST002 is as follows:
set session hw_model="VAX_4000_Model_108"
set session log="vax002.log"
set toy container="vax002.dat"
set rom container="vax002.rom"
load virtual_serial_line OPA0 port=10003 application="opa0.ht"

set PAA port[1]=11021 host[1]=”host001:11012”
set PAA port[3]=11023 host[3]=”host003:11032”

include h:\ourdisks\disksets.cfg

And the following is the CHARON-VAX configuration file for the emulated VAX 4000
Model 108 node named VAX003 running on HOST003:
set session hw_model="VAX_4000_Model_108"
Page 10 of 11

CHARON-VAX application note
set session log="vax003.log"
set toy container="vax003.dat"
set rom container="vax003.rom"

load virtual_serial_line OPA0 port=10003 application="opa0.ht"

set PAA port[1]=11031 host[1]=”host001:11013”
set PAA port[2]=11032 host[2]=”host002:11023”

include h:\ourdisks\disksets.cfg

For further information:
Software Resources International S.A.
P.O. Box 156
CH-1228 Plan-les-Ouates
Switzerland
WWW.SOFTRESINT.COM
Email: info@softresint.com
Tel: +41 22 794 1070

Page 11 of 11