ATTO Technology iPBridge 2500C User manual

ATTO Technology, Inc.
ATTO iPBridge
TM
2500C/R/D
Installation and Operation Manual
© 2005 ATTO Technology, Inc. All rights reserved. All brand or product names are trademarks of their
respective holders. No part of this manual may be reproduced in any form or by any means without the
express written permission of ATTO Technology, Inc.
8/2005 Document Control Number: PRMA-0335-000

Contents
1 iPBridge 2500 provide storage options ............................................1
iPBridge2500 features
Connectivity, infrastructure solutions
1.1 ATTO iPBridge 2500R/D ......................................................3
Dimensions
Environment
Power
SCSI interface
Ethernet interface
Serial interface
LED indicators
Installation instructions
1.2 ATTO iPBridge 2500C ..........................................................6
Dimensions
Environment
Power
SCSI interface
Ethernet interface
Serial interface
Installation instructions
2 Configuring the iPBridge ..................................................................9
Microsoft iSCSI Initiator changes
2.1 Getting an IP address ..........................................................10
2.2 NDMP configuration provides backup ...............................11
How NDMP works
Setting up NDMP
Procedure
Assign NDMP names to devices
2.3 Mapping devices: NDMP .....................................................13
Map devices automatically
Map devices manually
Assign NDMP names to devices
2.4 Mapping devices: iSCSI .......................................................15
Node names
Single Target mode
Map devices automatically
Map devices manually
Multiple Target mode
Automatically configure Multiple Target mode
Manually configure Multiple Target mode

2.5 Additional configurations ....................................................19
Change the current user name, password
Set the Real Time Clock
Create a read only password or user name
Configuring SCSI devices
SNMP protocol
3 ATTO ExpressNAV interface .............................................................21
Browser compatibility
To optimize ExpressNAV in Internet Explorer
Accessing ExpressNAV
Opening an ExpressNAV session
3.1 ExpressNAV pages ..............................................................23
Status
Serial Port Configuration
Time & Date Configuration
Ethernet Port Configuration
SCSI Configuration
iSCSI Configuration
Bridge Configuration
Mapping
Advanced CLI Configuration
Firmware
Restart
Help
4 Updating firmware .............................................................................25
Preliminary steps
Using ATTO ExpressNAV
Using FTP over GbE
5 Copying iPBridge configurations .....................................................26
Using FTP over GbE
Using ZModem over the serial port
6 Troubleshooting .................................................................................27
Inside out method
Check the host event log
Check the iPBridge event and trace logs
Visually inspect LEDs
Check for problems on attached devices
Check host versions
Check iPBridge product versions
Component check
Checking SCSI devices
Checking the iPBridge SCSI ports
Checking the serial port
Checking the iPBridge internal configuration
Checking iPBridge Ethernet ports
Checking the LAN/WAN
Checking the iSCSI Host Adapter or NIC
Checking the iSCSI OS driver
Checking the Operating System
Checking the applications
Performance issues

Checking SCSI devices
Checking iPBridge SCSI ports
Checking iPBridge Ethernet ports
Checking the LAN/WAN
Checking Ethernet Host Adapter or NIC
Checking the applications
Checking the host system
Checking the Operating System
7 Alternative interface options ............................................................33
Use the serial port or header
Use Telnet
7.1 CLI provides ASCII-based interface ...................................35
7.1.1 CLI commands summary .......................................36
7.1.2 General use commands .........................................39
Help
Password
ReadOnlyPassword
ReadOnlyUsername
RestoreConfiguration
SaveConfiguration
Username
VerboseMode
7.1.3 Maintenance commands ........................................41
Date
FirmwareRestart
MaxOpTemp
MinOpTemp
OpTempWarn
Password
Reserve
RestoreConfiguration
SCSIPortReset
SNTP
SNTPServer
SpeedWrite
SpeedWriteDefault
Time
TimeZone
Username
Zmodem
7.1.4 Diagnostic commands ...........................................43
BridgeModel
BridgeName
ClearEventLog
ClearTraceLog
DisplayEventLog
DisplayEventLogFilter
DisplayTraceLog
DisplayTraceLogFilter

DumpEventLog
DumpTraceLog
EventLog
EventLogFilter
Help
IdentifyBridge
Info
iSCSITargetNameDisplay
IsReserved
NDMPStatus
Ping
RMON
RouteDisplay
SCSIPortList
SCSITargets
SerialNumber
SNMPDumpMIB
SNMPExtendedTraps
SNMPTrapAddress
SNMPTraps
TailEventLog
Temperature
TraceLog
TraceLogFilter
Voltage
WrapEventLog
WrapTraceLog
7.1.5 SCSI configuration commands .............................47
SCSIInitID
SCSIPortBusSpeed
SCSIPortList
SCSIPortReset
SCSIPortResetOnStartup
SCSIPortSelTimeout
SCSIPortSyncTransfer
SCSIPortTermination
SCSIPortWideTransfer
SCSITargets
SpeedWrite
SpeedWriteDefault
VirtualDriveResponse
7.1.6 Serial port configuration commands ....................49
SerialPortBaudRate
SerialPortEcho
7.1.7 Ethernet commands ...............................................51
DPMTU
EthernetSpeed
Exit
IPAddress
IPDHCP
IPGateway
IPSubnetMask
Password
Ping

ReadOnlyPassword
RMON
Username
ReadOnlyUsername
7.1.8 NDMP commands ...................................................53
NDMPAuthType
NDMPMaxVersion
NDMPPortNumber
NDMPStatus
7.1.9 iSCSI commands ....................................................55
iSCSIAlias
iSCSIChap
iSCSIChapSecret
iSCSIPortNumber
iSCSITarget
iSCSITargetNameDisplay
iSNSLoginControl
iSNSServer
MultiTargetMode
7.1.10 Mapping commands .............................................57
AutoMap
iSCSITarget
iSCSITargetNameDisplay
MultiTargetMode
Route
RouteDisplay
SCSIInitID
SCSITargets
Appendix A ATTO iPBridge, FibreBridge family .................................i
iPBridge products
Fibre Bridge products
Appendix B Cabling ...............................................................................iii
SCSI cabling
Cable types
Examples
Connecting SCSI devices to SCSI ports
Ethernet connections
Appendix C Glossary .............................................................................v
Appendix D Safety standards and compliances .................................vii
Appendix E ATTO accessories .............................................................ix
Appendix F Warranty, contact information .........................................x
Manufacturer limited warranty
Contact ATTO Technology, Inc.

ATTO Technology Inc. iPBridge Installation and Operation Manual
1 iPBridge 2500 provide storage options
Two protocols available on the iPBridge 2500 allow storage devices such as hard drives, tape drives
and libraries and CD jukeboxes to attach easily to Internet Protocol networks such as Gigabit Ethernet.
The ATTO iPBridge supports the high throughput needs of streaming data transfers, optimizing
performance and management using ATTO Technology intelligent Bridging Architecture
TM
.
The ATTO iPBridge 2500 has two models
depending on the protocol you have chosen: either
the iSCSI protocol or the NDMP protocol.
The iSCSI protocol increases the capabilities and
performance of storage data transmission by
transmitting data over local area networks
(LANs), wide area networks (WANs), or the
Internet, providing location-independent data
storage and retrieval to enhance current and future
Storage Area Networks (SANs).
NDMP version 4.0 provides backup for network-
attached storage (NAS) tape and CD devices.
NAS devices are dedicated file servers and cannot
host applications such as backup software. NDMP
defines a common agent to interface between any
NAS device and any backup software program,
minimizing demand on network resources, and
enabling local backups and disaster recovery. The
protocol is being developed by the Storage
Networking Industry Association (SNIA) NDMP
Working Group.
Gigabit Ethernet (GbE) is a transmission
technology based on the Ethernet format and
protocol used in local area networks (LANs). It
provides a data rate of 1 billion bits per second
(one gigabit) as defined in the IEEE 802.3
standard.
intelligent Bridging Architecture, the engine
within ATTO FibreBridge
TM
and iPBridge
products, uses ATTO Data Routing Fabric
topology and ATTO Virtual Device Manager to
optimize performance.
The iPBridge 2500C/R/D provides a compact
embeddable, rack or desktop solution which may
be installed in a wide range of system
configurations. Uniquely designed to support the
high throughput needs for applications that
require streaming data transfers (data backup), the
iPBridge optimizes performance by using ATTO
Technology intelligent Bridging Architecture.
You may choose an iPBridge 2500C/R/D which
supports the iSCSI protocol or one which supports
the NDMP protocol, maximizing application,
system and network configuration flexibility and
support.
iPBridge2500 features
• Physical configuration: board, rackmount or
desktop
• 1 Gigabit data transfer rate per sec.
• 2 SCSI ports (SCSI bus 0, 1)
• Ultra 3 SCSI negotiation max capability
• Serial management port
• a 10/100/1000 Ethernet management port
(MPn) which may be used as a data port in the
iPBridge 2500 iSCSI model.
• two 10/100/1000 Ethernet data ports (DP0, DP1)
• iSCSI or NDMP protocol
• ATTO ExpressNAV browser-based
management
• Advanced diagnostics
SpeedWrite: a performance-enhancing capability
that significantly boosts Write performance by
efficiently managing Write commands between
host and a tape device. Using the iPBridge results
in a higher throughput and shorter backup times
compared to native Fibre tape or direct attached
SCSI tape libraries.
Advanced Diagnostics: software event-logging
capability time and date stamped by the real time
clock. You can also determine numerous status
and current configuration parameters.

Introduction
ATTO ExpressNAV: a web-based management
application that allows all of the configurable
settings for the iPBridge to be defined, viewed
and edited.
Connectivity, infrastructure solutions
The topology of a heterogeneous Storage Area
Network shown below demonstrates the critical
role ATTO products play in the design and
implementation of a SAN. Whether your
application needs are data-intensive or band-
width intensive, you need to store and manage
that data and then deliver it to end-users
efficiently. ATTO products have been engineered
with the highest performance and lowest cost
available today.
SCSI Tape Library
ATTO iPBridge 2700
4-Gb FC Switch
Possible storage
configurations
Ethernet
Fibre Channel
SCSI
embedded
ATTO iPBridge
1500/1550/2500
ATTO FibreBridge 2400
SCSI Tape Library
ATTO FibreBridge
FC model SCSI model
ATTO Diamond Storage Array
ATTO FibreCenter Hub
ATTO Celerity FC
storage adapter
ATTO ExpressPCI
FC storage adapter
GbE network
GbE Switch
ATTO ExpressPCI
SCSI storage adapter

3
ATTO Technology Inc. iPBridge Installation and Operation Manual
1.1 ATTO iPBridge 2500R/D
The ATTO iPBridge 2500R/D is a 1-Gigabit Ethernet to SCSI 1U full-rack bridge for midrange high
performance, cost effective solutions in enterprise environments.
The iPBridge 2500R/D includes a single power
supply, two Ethernet data ports, an Ethernet
management port which may be used as a data
port in the iPBridge 2500 iSCSI-configured
model, a serial management port and two SCSI
data and management ports. It includes a battery-
backed Real-Time-Clock, and an IP Time client
(RFC 1631 compliant).
Designed to fit into a 1U, full-rack enclosure, the
iPBridge 2500R/D supports side mounting so it
may be mounted into a standard 19-inch rack. The
ports and AC power are accessed from the rear of
the unit while LEDs showing port activity and
status are in the front and rear.
Dimensions
Width: 16.91 inches wide (42.95 cm)
Depth: 10 inches deep (25.4 cm)
Height: 1.72 inches high (4.32 cm (1U)
Weight: approximately 2 pounds
Environment
Operating temperature: 0-70° C external
Ambient air should not exceed 40°C.
User-configurable thermal sensor for automatic
shutdown default is 70°C
Blower and airflow: air enters through the slots in
the rear panel and exits through the blower on the
far end of the rear panel.
Humidity: 10-90% non-condensing
Power
Internal power supply: single-output 5VDC, 25-
watt open frame switching power supply with
universal input via a standard IEC320 adapter
mounted within the enclosure. Provides power for
the board and the cooling fan and is not hot
swappable.
Input voltage: 120-240VAC, 50-60 Hz, fused on
the power supply.
Power draw: 4 amps at 5.0V DC.
Battery-backed event log SRAM: A rechargeable
Lithium ion battery cell holds the memory in a
512KB SRAM for up to 30 days. If the iPBridge
has been disconnected from power, recharging
begins automatically when power is restored to
the system. The battery is fully charged after 36
hours of continuous power application.
WARNING
Risk of explosion if battery is removed
and/or replaced by an incorrect type.
Dispose of used batteries in accordance
with your local environmental regulations.
SCSI interface
The two independent SCSI ports on the iPBridge
2500R/D connect storage devices into the
Ethernet Storage Area Network (SAN). Each port
is completely independent from the other.
The ports are Ultra 3 LVD/SE SCSI busses with
68-pin “P” interface: 160 MB/sec. maximum
throughput, downward compatible with all forms
of single-ended SCSI.
The iPBridge supports all SCSI devices including
hard disk drives, tape drives, RAID controllers
and DVD, MO and CD libraries.
Ethernet interface
The two independent 10/100/1000 Ethernet RJ45
data ports, labeled Ethernet ports 0 and 1, use the
Intel 8254x family gigabit Ethernet chipset to
support telnet-based data transfer. A separate
10/100/1000 Ethernet standard RJ45 management
port, labeled Ethernet port 2, provides monitoring
and management through a command line
interface or ATTO ExpressNAV, a browser-based
interface. It may be used as a data port in the
iPBridge 2500 iSCSI-configured model.
GbE cables must be at least CAT-5E certified for
1000 Mb/sec. use.

4
Installation: ATTO iPBridge 2500R/D
Serial interface
The RS-232 serial port provides support for
remote monitoring and management through a
command line interface. It is set at the factory at
115,200 bps.
Pin outs of the RJ11 connector, part number CBL-
0911-001 are
LED indicators
The LED indicators can be viewed from the front
of the iPBridge 2500R/D.
Ethernet Link & Activity: Each Ethernet port has
its own set of LEDs to show link status and speed
as well as busy status.
SCSI 0 Activity, SCSI 1 Activity: each SCSI bus
has its own LED to show activity on that bus
(numbered 0 and 1).
Fault: should light yellow when power has been
applied, then immediately go dark. Software
activates the LED if there is a system error.
Exhibit 1.1-1 ATTO iPBridge 2500R/D connector side
Installation instructions
The ATTO iPBridge 2500R/D offers a variety of
ways to connect into a SAN.
1 Note the serial number of your iPBridge for later
use:
_____________________________________
2 Install the iPBridge 2500R/D in your desktop or
rackmount environment.
a. Attach “L” brackets so that front side
with the LEDs face front and the
connector side is at the back.
b. Install the iPBridge horizontally within
the rack so it does not reduce the air
flow within the rack.
3 Connect the AC power cord from the iPBridge
to the proper AC source outlet.
a. Properly ground the iPBridge to the
rack equipment. The earth ground
connection must be maintained.
b. The power requirements plus the
power draw of the other equipment in
the rack must not overload the supply
circuit and/or wiring of the rack.
4 Connect SCSI devices to the iPBridge. and
attach CAT 6 or CAT 5E cables to the GbE data
port(s) on the iPBridge. (For details, refer to the
Appendix, Cabling, on page iii).
5 Configure the iPBridge using the instructions in
Configuring the iPBridge on page 9.
Pin Description
2TXD
3Ground
4RXD
5Ground

5
ATTO Technology Inc. iPBridge Installation and Operation Manual
Exhibit 1.1-2 Overview of iPBridge 2500R/D standard 19-inch rack using a centered 1.25-inch (31.7 mm)
hole pattern
Ethernet management port
RS-232 port
Ethernet data ports
SCSI ports
Fault LED
SCSI activity LEDs
power receptacle
Centered 1.25" hole pattern
for "L" brakcets
10"
16.91"
1.72"
air vents
Back (connector) side
Front side with LEDs (see Exhibit 2.2-1)

6
Installation: ATTO iPBridge 2500C
1.2 ATTO iPBridge 2500C
The ATTO iPBridge 2500C is a 1-Gigabit Ethernet to SCSI embeddable cPCI bridge for high
performance, cost effective solutions in enterprise environments.
The iPBridge 2500C includes two Ethernet data
ports, an Ethernet management port which may be
used as a data port in the iPBridge 2500 iSCSI-
configured model, a serial management port and
two SCSI ports. It includes a battery-backed Real-
Time-Clock, and an IP Time client (RFC 1631
compliant).
Dimensions
Width: 6.193 inches
Length: 6.375 inches
Height of tallest component: .535 inches
Environment
Operating Temperature: 0-70°C external
Ambient air should not exceed 40°C.
User-configurable thermal sensor for automatic
shutdown default is 70°C
Humidity: 10-90% non-condensing
Recommended airflow: 11 cubic feet per minute
Power
The iP2500C board may be powered from the
cPCI backplane or a 6-pin connector.
Input voltage: 5.0V DC ±5% derived from cPCI
or 6-pin connection. Fused at the backplane and
hot swap protection.
Power draw: 3 amps at 5.0V DC. Battery-backed
event log SRAM: A rechargeable Lithium ion
battery cell or Super Cap holds the memory in a
512KB SRAM based on the following chart.
Recharging begins automatically when power is
restored to the system.
WARNING
Risk of explosion if the battery is removed
and/or replaced by an incorrect type.
Dispose of used batteries in accordance
with your local environmental regulations.
SCSI interface
The two independent SCSI ports on the iPBridge
2500C connect storage devices into the Ethernet
Storage Area Network (SAN). Each port is
completely independent.
The ports are Ultra 3 LVD/SE SCSI busses with
68-pin “P” interface: 160 MB/sec. maximum
throughput, downward compatible with all forms
of single-ended SCSI.
The iPBridge supports all SCSI devices including
hard disk drives, tape drives, RAID controllers
and DVD, MO and CD libraries.
Ethernet interface
The two independent 10/100/1000 GbE RJ45 data
ports, labeled Ethernet port 0 and Ethernet port 1,
use the Intel 8254x family gigabit Ethernet
chipset to support telnet-based data transfer. A
separate 10/100/1000 Ethernet standard RJ45
management port, labeled Ethernet port 2 and
which may be used as a data port in the iPBridge
2500 iSCSI-configured model, provides
monitoring and management through ATTO
ExpressNAV, a browser-based interface.
Time to charge
battery or CAP
Backup power
duration
Battery
(typical)
36 hours
continuous power
30 days
Super CAP
worst case
60 seconds 3 hours
Super CAP
typical
>320 seconds 5-15 hours

7
ATTO Technology Inc. iPBridge Installation and Operation Manual
GbE cables must be at least CAT-5E certified for
1000 Mb/sec. use.
Serial interface
The RS-232 serial port provides support for
remote monitoring and management through a
command line interface. It is set at the factory at
115,200 bps.
Pin outs of the RJ11 connector, part number CBL-
0911-001 are
Installation instructions
1 Install the iPBridge 2500C in the target device.
(See the board layout diagram below)
2 Connect SCSI devices to the iPBridge. and
attach CAT 6 or CAT 5E cables to the GbE data
port(s) on the iPBridge. (For details, refer to the
Appendix, Cabling, on page iii).
3 Connect to power.
4 Configure the iPBridge using the instructions in
Configuring the iPBridge on page 9.
Exhibit 1.2-1 ATTO iPBridge 2500C faceplate
Pin Description
2TXD
3 Ground
4RXD
5 Ground
SCSI ports Ethernet data ports RS-232 port
Ethernet
management
port Fault LED
SCSI LEDs
Ethernet port link and activity LEDs
SCSI Port 0
SCSI Port 1
Fault
Management Port
RS-232
Data Port 0 Data Port 1

8
Installation: ATTO iPBridge 2500C
Exhibit 1.2-2 ATTO iPBridge 2500C board layout
Mounting hole
5.756"
Mounting hole
-.216 " 6.158"
5.974 " -.218"
Ethernet
management port
RS-232 port
Ethernet
data ports
SCSI ports
0"
0"
Mounting hole
6"

9
ATTO Technology Inc. iPBridge Installation and Operation Manual
2 Configuring the iPBridge
Set up your iPBridge by first getting an IP address, then use ATTO ExpressNAV to map devices. Default
values are appropriate for most configurations, but may be modified for your needs using ATTO
ExpressNAV.
Configuration of the ATTO iPBridge, also known
as iPBridge Services, is available through the
ATTO ExpressNAV, a browser-based interface, or
the Command Line Interface (CLI).
ATTO iPBridge Services configures and tunes the
iPBridge for many different environments and
applications, updates the firmware, configures the
addresses of the connected devices, monitors
status and reports on hardware.
To use the iPBridge, you must
1 Know the IP address for the iPBridge. (Refer to
Getting an IP address on page 10).
2 Map devices so that the iPBridge can access
the devices in your network. (Refer to Mapping
devices: NDMP on page 13 and Mapping
devices: iSCSI on page 15).
Additionally, it is best practice to change the
default user name and password and to set the
Real Time Clock. Refer to Additional
configurations on page 19
Any changes must be saved and will not take
effect until the iPBridge is restarted.
Note
The recommended management tool for the
iPBridge is ATTO ExpressNAV. For details on
the interface, refer to
ATTO ExpressNAV
interface on page 21.
Microsoft iSCSI Initiator changes
Installing the file MSiSCSI_Adj.reg , found on
the ATTO iPBridge installation CD, makes
several Windows operating system registry
changes to optimize the ATTO iPBridge
performance when using the Microsoft iSCSI
Initiator.
1 Install Microsoft iSCSI Initiator.
2 Double click on the file MSiSCSI_Adj.reg
found on the installation CD.
The resident Windows operating system is
updated to use optimal settings.

10
Configuration: Ethernet
2.1 Getting an IP address
Set up your iPBridge by first getting an IP address, then use ATTO ExpressNAV to map devices.
The iPBridge is set up by default to request an IP
address from a DHCP server. If you do not have a
DHCP server to assign IP addresses to devices,
get an IP address from your network
administrator.
Use the QuickNAV utility from the CD included
with your iPBridge to find your iPBridge on your
network.
1 Work from the computer attached to the
iPBridge on the same broadcast domain. Find
and download the QuickNAV utility,
QuickNAV-windows.exe, from the CD
included with your iPBridge.
2 Turn on the iPBridge.
Wait for the iPBridge Ready LED to light, up to
three minutes, before proceeding.
3 Run the QuickNAV application.
a. Click Next on the QuickNAV Wizard
page.
b. Select your iPBridge serial number
from the list of choices displayed.
c. Click Next.
• If you are using DHCP, note the IP
Address assigned by the server:
_________________________________
• If you are not using DHCP, configure the
iPBridge with the IP Address and
Subnet Mask given to you by your
network administrator.
_________________________________
_________________________________
d. Click Launch Browser.
Your browser points to the
ExpressNAV splash screen.
4 Enter the user name and password values.
Note
The default values are username : “root” and
password : “Password”. The user name is
case insensitive and the password is case
sensitive.
The iPBridge Status page appears.
5 Go on to Mapping devices: NDMP on page 13
or Mapping devices: iSCSI on page 15
depending on your model of the iPBridge 2500.

11
ATTO Technology Inc. iPBridge Installation and Operation Manual
2.2 NDMP configuration provides backup
NDMP (Network Data Management Protocol) provides backup for network-attached storage (NAS)
devices. NAS devices are dedicated file servers and cannot host applications such as backup software.
NDMP defines a common agent to interface between any NAS device and any backup software program,
minimizing demand on network resources, and enabling local backups and disaster recovery.
Note
For NDMP-configured iPBridge 2500 models
only
The ATTO iPBridge 2500, using the NDMP
Version 4 Protocol Specification, 10/2001, (-
skardal-ndmp4.03.doc), allows you to back up
critical data locally using any combination of
network-attached servers, backup devices and
management applications from a central control,
without taxing network traffic, by separating the
data path and the control path.
How NDMP works
The NDMP protocol allows data backup and
restoration over telnet networks using file-level
commands, rather than block-level IO
instructions.
The typical NDMP setup includes
• a Data Service (usually disks)
• a Tape Service
• a client in control of the backup process called a
Data Management Application (DMA).
The DMA controls the NDMP session. There is a
master-slave relationship between the DMA and
the data/tape servers. The iPBridge 2500
implements the Tape Service, along with a SCSI
Service, to provide access to media changer
devices.
The iPBridge 2500 platform provides several
different types of management capability,
including telnet/FTP through the two GigE data
ports and an Ethernet 10/100/1000 management
port which may be used as a data port in the
iPBridge 2500 iSCSI-configured model, serial
CLI management, and standard bridge hardware
health checking.
A typical NDMP application involves a drive
array, a host computer and a tape library. the host
computer may be attached to the disk and tape
drives by any of several methods/technologies.
The iPBridge uses Ethernet and Internet
protocols.
The following example describes a host, Ethernet,
tape library configuration.
1 The DMA sends messages to the tape library’s
SCSI Server to pick the appropriate cartridge
and load it in the tape drive.
2 The DMA sends commands to the tape drive to
position the tape and configure the tape for
writing (block size, etc.).
3 The DMA opens a connection to the Data
Server to exchange backup information.
4 The DMA commands the Tape Server to
prepare to receive data.
5 The Tape Server responds with addressing
information.
6 The DMA passes the address to the Data
server.
7 The Data Server and Tape Server send data
directly to each other.
8 Metadata generated by the DMA is written to
tape to indicate the end of files, directories, path
names, etc., passed through to the tape server
between backup data transfers.
• NDMP uses a windowing mechanism in
which the Tape Server writes a portion of the
data, then pauses and waits for the DMA to
take charge. The DMA may start a new
window or write some Metadata.
• The DMA may also move the tape while the
transfer is paused. Once the DMA has
finished with the Metadata, a new window is
established and the transfer from the Data
Server to the Tape Server continues.
• The Data Server has no notification of the
Tape Server being paused, so it must rely on
the TCP stack to queue up data transferred
during the pause time, and to implement flow
control when queues are full.