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Hitachi Vantara Knowledge

Data and power cables

The storage system supports a variety of data and power cables for specific hosting environments.

Required cables

The quantities and lengths of the cables required for storage system installation vary according to the specific storage system and network configuration. Fibre Channel and iSCSI cables are used to connect the controllers to a switch or host. Serial-attached SCSI (SAS) cables are used to connect drive trays to controllers and other drive trays.

The following table describes the cables required to perform storage system connections at the time of installation.

Interface type

Connector type

Cable requirements

Fibre Channel

LC-LC

Use a Fibre Channel cable to connect the Fibre Channel ports on each controller to a host computer (direct connection), or to or several host computers via a Fibre Channel switch. See the note and table below.

iSCSI (optical)

LC-LC

Use an optical Ethernet cable to connect the iSCSI 10 Gb SFP ports on each controller to a host computer (direct connection), or to several host computers via an Ethernet switch.

iSCSI (copper)

RJ-45

Use a shielded Category 5e or 6a Ethernet cable to connect the iSCSI 10 Gb RJ-45 ports on each controller to a host computer (direct connection), or to several host computers via an Ethernet switch.

SAS

SAS optical

Connects the controller to a drive tray or a drive tray to another drive tray. Two SAS cables are provided with each drive tray. SAS cables are also used to connect NAS modules to switches.

Ethernet

RJ-45

Four shielded Category 5e or 6a Ethernet cables are required for connecting the SVP to the controllers, management console PC, and network switch.

Note The maximum distances in a typical Fibre Channel SAN depend on the kind of optical fiber used and its diameter. The following table lists the maximum supported Fibre Channel cable length based on cable size and port speed.

Cable size

Speed

Maximum cable length

9 micron

1 Gbps

1 km

(3281 ft)

2 Gbps

2 km

(6562 ft)

50 micron

2 Gbps

300 m

(984.2 ft)

4 Gbps

150 m

(492.1 ft)

8 Gbps

50 m

(164 ft)

16 Gbps

35 m

(115 ft)

62.5 micron

2 Gbps

100 m

(328.1 ft)

4 Gbps

70 m

(230 ft)

8 Gbps

21 m

(69 ft)

Fibre Channel cables

The storage system supports Fiber Channel connections to hosts. For details about configuring FC host connections, see the Provisioning Guide.

NoteDue to high-speed serial data transfer via Fibre Channel, use high-quality FC cables that comply with the Fibre Channel-PH standard.

The following figure shows FC direct connection and FC connection through a switch.

The following table lists the data transfer rates and provides the maximum cable lengths.

Data transfer rate

Maximum length of cable

Multimode cable

Single mode cable

OM2

OM3

OM4

2 Gbps 984.25 ft (300 m) 1640.4 ft (500 m) 3280.8 ft (10 km)
4 Gbps 493 ft (150 m) 1246.72 ft (380 m) 1312.3 ft (400 m)
8 Gbps 164.04 ft (50 m) 493 ft (150 m) 623.36 ft (190 m)
16 Gbps 114.8 ft (35 m) 328.08 ft (100 m) 410.1 ft (125 m)
32 Gbps 65.62 ft (20 m) 229.7 ft (70 m) 328.08 ft (100 m)

The following table lists specifications of the Fibre Channel interface cable.

Cable type

Interface

Cable mode name

Nominal

Cable

Connector

One side

Other side

LC-LC cable (shortwave) Optical Equivalent to DXLC-2P-PC-xxM-GC50, 125-2SR (OMx) 50, 125 μm, 62.5, 125 μm Multimode

Wavelength: 850 nm

LC connector LC connector

LC-LC cable (longwave)

DXLC-2PS-SPC-xxM-SMC 10/125-2SR 9/125 μm Singlemode

Wavelength: 1300 nm

The following figure shows the connector used for optical interfaces.

The following figure shows the type of optical connector that connects the storage system Fibre Channel ports.

  • LC connector type
  • Connector type LC duplex receptacle connector
  • Interval 6.25 mm flat type, two rows

iSCSI cables

The storage system supports iSCSI connections to hosts. For details about configuring iSCSI host connections, see the Provisioning Guide.

Cable specifications for iSCSI optical interface

Cable type

Interface

Cable mode name

Nominal

Cable

Connector

One side

Other side

LC-LC cable Optical Equivalent to DXLC-2P-PC-xxM-GC50, 125-2SR (OMx)

50, 125 mm Multimode Wavelength: 850 nm

LC connector LC connector

The following figure shows the connector used for optical interfaces.

The following figure shows the type of optical connector that connects the storage system optical iSCSI ports.

  • LC connector type
  • Connector type LC duplex receptacle connector
  • Interval 6.25 mm flat type, two rows
Cable specifications for 10 Gbps iSCSI copper interface

Cable type

Maximum cable connection length

Data transfer

Transmission band

Cable

Connector

Category 5e or 6a LAN cable

100 m

1 Gbps

1000BASE-T

STP ( use an STP cable that suppresses radio noise)

RJ-45

Category 6a LAN cable

50 m

10 Gbps

10GBASE-T

STP ( use an STP cable that suppresses radio noise)

RJ-45

The following figure shows a 10 Gbps iSCSI cable.

iSCSI standards

The following standards apply to the management, maintenance, and iSCSI data ports. To configure this system, use switches that comply with the following standards:

  • IEEE 802.1D STP
  • IEEE 802.1w RSTP
  • IEEE 802.3 CSMA/CD
  • IEEE 802.3u Fast Ethernet
  • IEEE 802.3z 1000 BASE-X
  • IEEE 802.1Q Virtual LANs
  • IEEE 802.3ae 10 Gigabit Ethernet
  • RFC 768 UDP
  • RFC 783 TFTP
  • RFC 791 IP
  • RFC 793 TCP
  • RFC 1157 SNMP v1
  • RFC 1231 MIB II
  • RFC 1757 RMON
  • RFC 1901 SNMPv2

iSCSI specifications

Item

Specification

Comments

iSCSI target function Supported N/A
iSCSI target function Supported TrueCopy® only
iSCSI ports 2 per interface board

VSP Gx00 models: Maximum 32 per iSCSI system

Connection methods Direct and switch connections
Host connections 255 (maximum per iSCSI port) With Linux software initiator, the maximum number decreases.
Path failover HDLM1 Supports Microsoft MPIO (Multi Path I/O)
Link 10 Gbps SFP+ N/A
Transfer speed 10 Gbps N/A
Connector type LC N/A
Cable Optical OM3, OM2 MMF cable N/A
Network switch L2 or L3 switch Should comply with IEEE802.3ae
Switch cascading Maximum: 5 switches or fewer Minimum number of cascading switches is recommended.
MAC address Per port (fixed value) Factory setting: World Wide Unique value. Cannot be changed.
Maximum transfer unit (MTU) 1,500, 4,500, 9,000 bytes (Ethernet frame) Jumbo frame, MTU size greater than 1500
Link aggregation Not supported N/A
Tagged VLAN Supported N/A
IPv4 Supported N/A
IPv6 Supported

Note the following precautions:

  • When iSCSI Port IPv6 is set to Enabled, if the IPv6 global address is set to automatic, the address is determined by acquiring a prefix from an IPv6 router.

  • If the IPv6 router does not exist in the network, the address cannot be determined. As a result, an iSCSI connection might be delayed. When an iSCSI Port IPv6 is set to Enabled, verify the IPv6 router is connected to the same network, and then set IPv6 global address automatically.

Subnet mask Supported N/A
Gateway address Supported N/A
DHCP N/A N/A
DNS N/A N/A
Ping (ICMP ECHO) Transmit, Receive Supported N/A
IPsec2 N/A N/A
TCP port number 3260 Changeable among 1 to 65,535. Observe the following if changing values:
  • The setting of the corresponding host should also be changed to log in the new port number.
  • The new port number might conflict with other network communication or be filtered on some network equipment, preventing the storage system from communicating through the new port number.
iSCSI name Both iqn3 and eui4 types are supported The unique iqn value is automatically set when a target is made. iSCSI name is configurable.
Error recovery level 0 (zero) Error recovery by retrying from host. Does not support Level 1 and Level 2.
Header digest Supported Detects header error or data error with iSCSI communication. The storage system follows the host's digest setting. If digest is enabled, the performance degrades. The amount of the degradation depends on factors such as host performance of host and transaction pattern.
Data digest Supported
Maximum iSCSI connections at one time 255 per iSCSI port N/A
CHAP Supported Authentication: login request is sent properly from host to storage. CHAP is not supported during discovery session.
Mutual (2-way) CHAP Supported (not available if connected to Linux software initiator) Authentication: login request is sent properly from host to storage.
CHAP user registration Max 512 users per iSCSI port N/A
iSNS Supported With iSNS (name service), a host can discover a target without knowing the target's IP address.

Note:

  1. JP1, HiCommand Dynamic Link Manager. Pass switching is achieved. Not supported on Windows Vista and Windows 7 operating systems.
  2. IP Security. Authentication and encryption of IP packets. The storage system does not support IPsec.
  3. iqn: iSCSI Qualified Name. The iqn consists of a type identifier, "iqn," a date of domain acquisition, a domain name, and a character string given by the individual who acquired the domain. Example: iqn.1994-04.jp.co.hitachi:rsd.d7m.t.10020.1b000.tar
  4. eui: 64-bit Extended Unique Identifier. The eui consists of a type identifier, "eui," and an ASCII-coded, hexadecimal, EUI-64 identifier. Example: eui.0123456789abcdef

Managing cables

Organize cables to protect the integrity of your connections and allow proper airflow around your storage system.

Observing bend radius values

Never bend cables beyond their recommended bend radius. The following table provides general guidelines for minimum bend radius values, but you should consult the recommendation of your cable manufacturer.

Cable type

Minimum bend radius values

Fibre Channel

40 mm (1.73 inch)

iSCSI optical

40 mm (1.73 inch)

Category 5 Ethernet

Four times the outside diameter of the cable

SAS

40 mm (1.73 inch)

Protecting cables

Damage to the cables can affect the performance of your storage system. Observe the following guidelines to protect the cables:

  • Keep cables away from sharp edges or metal corners.
  • When bundling cables, do not pinch or constrict the cables.
  • Do not use zip ties to bundle cables. Instead, use Velcro hook-and-loop ties that do not have hard edges and which you can remove without cutting.
  • Never bundle network cables with power cables. If network and power cables are not bundled separately, electromagnetic interference (EMI) can affect your data stream.
  • If you run cables from overhead supports or from below a raised floor, include vertical distances when calculating necessary cable lengths.
  • If you use overhead cable supports:
    • Verify that your supports are anchored adequately to withstand the weight of bundled cables.
    • Gravity can stretch and damage cables over time. Therefore, do not allow cables to sag through gaps in your supports.
    • Place drop points in your supports that permit cables to reach racks without bending or pulling.
  • Unintentional unplugging or unseating of a power cable can have a serious impact on the operation of an enterprise storage system. Unlike data cables, power connectors do not have built-in retention mechanisms to prevent this from happening.

    To prevent accidental unplugging or unseating of power cables, the storage system includes a rubber cable-retention strap near the AC receptacle on each controller. These straps, shown in the following image, loop around the neck of a power cable connector, and the notched tail is slipped over the hook of the restraining bar fixed to the storage system.

Cabling full-width modules

When cabling full-width modules, route the cables horizontally, so that they do not interfere when replacing a module.

Ensuring adequate airflow

Bundled cables can obstruct the movement of conditioned air around your storage system.

  • Secure cables away from fans.
  • Keep cables away from the intake holes at the front of the storage system.
  • Use flooring seals or grommets to keep conditioned air from escaping through cable holes.
Preparing for future maintenance

Design your cable infrastructure to accommodate future work on the storage system. Give thought to future tasks that will be performed on the storage system, such as locating specific pathways or connections, isolating a fault, or adding or removing components.

  • Purchase colored cables or apply colored tags.
  • Label both ends of every cable to denote the port to which it connects.