4. Physical mounting

4.1. Preparing the rack

4.1.1. Rail distance

The Bow-2000 mounting system requires a rail-to-rail distance of 720mm. This document describes the adjustments required for an AR3300SP rack. If using a different rack this rail distance must be observed.

4.1.2. Unpacking the rack

Follow the instructions to remove the outer packaging of the APC AR3300SP rack, ensuring that you safely store these materials for later repackaging. Do not remove the rack from the shock pallet. Remove the white bag (Fig. 4.1) from the rack. This contains screws and cage nuts to be used in the assembly of the components into the rack.

Fig. 4.1 White bag with rack

4.1.3. Removing the side panels and doors

Remove the front and rear doors from the rack. Ensure the earth straps (Fig. 4.2) are disconnected before the doors are removed.

Fig. 4.2 Rack earth straps

Remove the top and bottom side panels. The vertical accessory channels should be positioned at the very front and very rear of the rack. If necessary, move these from their shipping positions (Fig. 4.3).

Fig. 4.3 Top and bottom side panel removal

4.1.4. Removing the vertical accessory channels

Using a Torx TX30 screwdriver, remove two accessory channels from the rack (Fig. 4.4).

Fig. 4.4 Accessory channel removal

4.1.5. Adjusting the rear accessory channels

Set the rear accessory channel to the furthest position in the rack. Tighten up the screws ensuring the teeth engage into the slots in the rail, as shown in Fig. 4.5.

Fig. 4.5 Rear accessory channel (ensure teeth engage in slots)

4.1.6. Adjusting the rear vertical rails

Using a Torx TX30 screwdriver, make both rear vertical rack rails loose and freely movable.

Position the rear vertical rack rails such that there is 20mm of distance between the rear face of the vertical rack rail and the racks rear frame. This should result in a square symbol being visible through the alignment window at the top and bottom of the rail, as shown in Fig. 4.6.

Fig. 4.6 Rear vertical rails

Secure the rail into position by moving the TX30 screws back upwards such that the teeth engage with both the supporting rails. This must be done at the top and bottom of the bracket.

4.1.7. Adjusting the front vertical rails

Using a Torx TX30 screwdriver, make both front vertical rack rails loose and freely movable. Install the accessory channels in the front of the rack (one on the left hand side, one on the right hand side) at the frontmost position possible, moving the TX30 screws back upwards such that the teeth engage with both the supporting rails. This must be done at the top and bottom of the bracket.

Note

To ensure the clips on the accessory channels align with the channel in the rack, lift the accessory channels through the cut-out in the top of the rack and then drop them down onto the channels.

Move the vertical rack rails tight against the vertical cable organisers such that only a single diamond symbol is visible through the alignment window at the top and bottom of the rail, see Fig. 4.7.

Fig. 4.7 Front vertical rail alignment

Secure the rail into position by moving the TX30 screws back upwards such that the teeth engage with both the supporting rails. This must be done at the top and bottom of the bracket.

4.1.8. Installing the rack rails

Fig. 4.8 Bow-2000 rack rail kit: unboxed

The Bow-2000 rail kit comprises two mated inner and outer rack rails and an accessory bag containing screws. The inner rail affixes to the body of the Bow-2000 and the outer rail affixes to the vertical rack rails in the server cabinet. Firstly, separate the mated inner and outer rails:

1. Fully extend the rails by pulling on the end which has the captive thumb screw attached (Fig. 4.9):

Fig. 4.9 Bow-2000 rack rail kit: extended rails

2. Whilst pulling on the thumb screw end of the rails, push the white plastic release tab towards the thumb screw end (Fig. 4.10):

Fig. 4.10 Bow-2000 rack rail kit: white release tab

3. The inner and outer rails will now separate (Fig. 4.11):

Fig. 4.11 Bow-2000 rack rail kit: inner and outer rails separated

Mate the inner rails (the thinner of the two separated rails which has a captive thumb screw at one end) to the body of the Bow-2000. Note that the inner rails are mirrored and are not handed. As such, the procedure for inner rail fixing is the same for the left and right hand inner rails.

The inner rail should be oriented such that the captive thumb screw end is at the end of the Bow-2000 containing the network ports.

To affix the inner rail to the body of the Bow-2000:

1. Offer up the inner rail to the side of the Bow-2000 and ensure that all fixing pins are sitting within the enlarged opening of the retention channel (Fig. 4.12):

Fig. 4.12 Bow-2000 rack rail kit: fixing pins

2. Push the inner rail towards the end of the Bow-2000 containing the network ports, you should hear a click as the latching mechanism locks behind the head of a fixing pin (Fig. 4.13):

Fig. 4.13 Bow-2000 rack rail kit: fixing pins locked

3. Ensure all fixing pins are correctly engaged with their respective retention channels.

4. Locate the four flat head fixing screws from the rack rail accessory bag (Fig. 4.14):

Fig. 4.14 Bow-2000 rack rail kit: flat head fixing screws

5. Using the above screws, affix the inner rail to the body of the Bow-2000 (Fig. 4.15):

Fig. 4.15 Bow-2000 rack rail kit: attaching inner rail to Bow-2000

The inner rails are now securely affixed to the Bow-2000 body. Place the outer rails to one side for later use (Fig. 4.16):

Fig. 4.16 Bow-2000 rack rail kit: outer rails

4.1.9. Installing PDU brackets

Install four cage nuts on the outside at the top and bottom to both of the accessory channels as shown below (Fig. 4.17 and Fig. 4.18).

Fig. 4.17 Top PDU bracket cage nuts

Fig. 4.18 Bottom PDU bracket cage nuts

Screw the PDU support brackets to the inside of the cabinet. The PDU brackets should be installed at the rear of the rack: one bracket on top with 9cm distance from the top of rack and one bracket on the bottom with 12cm distance from the bottom of rack. Fig. 4.19 illustrates this. Follow the PDU bracket installation instructions.

Fig. 4.19 PDU support bracket

4.2. Installing the equipment

The following sections describe the installation of the Bow-2000(s) and server into the rack.

Clearly in the case of a single Bow-2000 DA system only one Bow-2000 is installed. If subsequently you plan to expand to a Bow Pod₁₆ DA system, you may wish to leave enough free rack space (3 rows) between the Bow-2000 and the server.

In the case of a Bow Pod₁₆ DA system, four Bow-2000s are installed. All Bow-2000s and the server should be adjacent to each other in the rack.

The installation of PDUs is not covered in this guide since that will depend upon the PDUs selected.

4.2.1. Installing the Bow-2000 IPU-Machines

Earlier in the guide we affixed the inner rack rails to the Bow-2000 body. The next step in installing the Bow-2000 IPU-Machines is to install the outer rack rails into the rack.

It is possible to identify the front and rear of the outer rail by finding the large metal latching mechanism. This is to be located at the rear of the rack. The outer rail is also embossed with the text “FRONT” at the front end of the rail.

The outer rail large metal latch end is to be installed at the rear of the rack, as shown in Fig. 4.20.

Fig. 4.20 Attachment point for Bow-2000 outer rail

For each rack U in U1 through U16 (inclusive), perform the steps below with both the left hand and right hand outer rack rails:

1. Pull on each end of the outer rail to adjust the rail length to suite your rack

2. Locate the front end of the outer rail and hold it behind the square holes in the vertical rack rail for your installation U. Pull the outer rail towards the vertical rack rail and the latching mechanism will click and hold the outer rail in place (Fig. 4.21):

Fig. 4.21 Bow-2000 outer rail latching mechanism

3. Locate the rear end of the outer rail and slightly open the large metal latch, then press the upper and lower locating pins into the square holes in the vertical rack rail. Release the large metal latch and the outer rail will now be secured to the vertical rack rail (Fig. 4.22):

Fig. 4.22 Bow-2000 outer rail secured to vertical rack rail

4. Included in the rack rail accessory bag are two screws and two washers. One screw with one washer should be screwed through the vertical rack rail and into the outer rack rail threaded hole. The washer should be used in such a way that the washer sits flush with the head of the screw –like a cup. The screws and how they fit are shown in Fig. 4.23 and Fig. 4.24.

This should be repeated for both outer rack rails.

Fig. 4.23 Bow-2000 rack rail kit: outer rail screws and washers

Fig. 4.24 Bow-2000 rack rail kit: outer rail screws and washers attached

Next, to install an Bow-2000 unit into the rack rails, work your way through the following steps in order:

1. Pull the sliding rail located within the outer rack rail completely forward such that it locks into the fully extended position (Fig. 4.25):

Fig. 4.25 Bow-2000 rack rail kit: sliders fully extended

2. Place the Bow-2000 onto an appropriate server lift and adjust the height such that it is suitable for the sliders (Fig. 4.26). If a lift is not available, this is a two person operation.

Fig. 4.26 Server lift for Bow-2000

3. Slide the protruding inner rails into the receiving channel of the extended outer rails (Fig. 4.27):

Fig. 4.27 Slide Bow-2000 inner rails into outer rails

4. Whilst the server lift is supporting the full weight of the Bow-2000, slide the Bow-2000 into the extended outer rails until you feel both sides engage a stopping mechanism (Fig. 4.28).

5. Simultaneously pull on the blue tabs for the release mechanism at each side of the Bow-2000 and then push the Bow-2000 unit fully into the rack (Fig. 4.29):

Fig. 4.28 Sliding Bow-2000 into rack

Fig. 4.29 Blue tab release mechanism

6. Screw the captive thumb screw into the inner rack rail (Fig. 4.30):

Fig. 4.30 Screwing captive thumb screw into inner rack rail

4.2.2. Installing the host server

This section describes the installation of a Dell RG525 server. Other approved and qualified servers are available. To find out more speak to Graphcore sales or your Graphcore channel partner for options.

The server should be installed above the Bow-2000(s).

Note

The R6525 is installed such that the rear of the server (containing the management and data ports) is the opposite side of the rack to the ports on the front of the Bow-2000(s). This is due to airflow direction.

1. Remove and discard the cable management arm brackets from the rear of each tool-less sliding rail.

   

2. Install the tool-less sliding rail kit(s) in the required location.

   

3. Pull out the rail and fit the server to the rail ensuring the T pins on the side of the server locate in the slots on the rail. Ensure that the power supplies on the server face the rear of the rack.

   Note

   Use an appropriate server lift or have two people installing the servers to ensure correct fitting

4. Push the server gently from the front to lock it into the slides then press the tab on the side of the slides and push the server fully home in the rack. Repeat the above process for each server if installing multiple servers.

5. Remove the Velcro tape from the light pipes on the rear of the servers.

6. Remove the small plastic tab on the left front side of the server bezel and clip the bezel in place on the front of the server ensuring the connection pins on the right-hand side of the bezel line up with the connector on the server, as shown below:

   

4.2.3. Installing the PDUs

The method for installing the PDUs will depend on the choice of PDU type and location. If the PDUs are to be installed horizontally within the rack, the recommendation is that these are positioned beneath the lowest Bow-2000. Allowing some space between the lowest Bow-2000 and the PDUs may make power cabling easier.

4.3. Cabling the system

The following sections detail the wiring of the Bow Pod DA system within the rack. The cabling is very straightforward, as indicated by diagrams of the completed systems in Fig. 4.31 and Fig. 4.32. The following sections take you through wiring up each group of cables in turn.

Fig. 4.31 Single Bow-2000 DA system

Fig. 4.32 Bow Pod₁₆ DA system

4.3.1. Bow-2000 to Bow-2000 IPU-Link connectivity (OSFP)

Note

This step is only required for Bow Pod₁₆ DA systems.

There are 8 OSFP IPU-Link ports on the right side of each Bow-2000.

Fig. 4.33 Bow-2000 IPU-Link ports

Using 0.3M OSFP cables, link the top row of four IPU-link ports (5-8) to the bottom row of four IPU-link ports (1-4) in the Bow-2000 that is installed directly above (see Table 4.1 and Fig. 4.34). The top row (5-8) of the top-most Bow-2000 (#4) and the bottom row (1-4) of the bottom-most Bow-2000 (#1), are left unconnected.

1. Before attempting to install the OSFP cables, it is beneficial to manipulate the cable to form a tight loop such that the white side of the connector tabs face away from each other. During manufacture and shipping, the cables can form quite a stiff shape, so manipulating the cables before installing them reduces stresses on the socket during install.

2. After installing a cable, pull gently on the black cable to ensure the plugs are firm in the sockets on the Bow-2000.

Note

The white tab is on the top of the cable when inserted into the Bow-2000.

Table 4.1 Bow-2000 IPU-Link port mapping

From Bow-2000 OSFP port	To Bow-2000 OSFP port	Cables
Bow-2000 # 3 IPU-Link ports 5,6,7,8	Bow-2000 # 4 IPU-Link ports 1,2,3,4	OSFP 0.3m
Bow-2000 # 2 IPU-Link ports 5,6,7,8	Bow-2000 # 3 IPU-Link ports 1,2,3,4	OSFP 0.3m
Bow-2000 # 1 IPU-Link ports 5,6,7,8	Bow-2000 # 2 IPU-Link ports 1,2,3,4	OSFP 0.3m

The figure below shows the Bow-2000 to Bow-2000 IPU-Link cabling for a Bow Pod₁₆ DA system.

Fig. 4.34 Bow Pod₁₆ DA system (IPU-Links)

4.3.2. Bow-2000 to Bow-2000 Sync-Link cabling (Cat5e)

Note

This step is only required for Bow Pod₁₆ DA systems.

There are 8 Cat5e Sync-Link ports in the middle of each Bow-2000.

Fig. 4.35 Bow-2000 Sync-Link ports

Using 0.15m red Ethernet Cat5e cables, link the top two central Sync-Link ports (6-7) of each Bow-2000 to the bottom two central Sync-Link ports (2-3) of the Bow-2000 that is installed directly above (see Table 4.2 and Fig. 4.36). The top row (5-8) of the top-most Bow-2000 (#4) and the bottom row (1-4) of the bottom-most Bow-2000 (#1), are left unconnected.

Table 4.2 Bow-2000 Sync-Link port mapping

From Bow-2000 Sync-Link connections	To Bow-2000 Sync-Link connections	Cables
Bow-2000 # 3 Sync-Link ports 6-7	Bow-2000 # 4 Sync-Link ports 2-3	2x Cat5e 0.15m red
Bow-2000 # 2 Sync-Link ports 6-7	Bow-2000 # 3 Sync-Link ports 2-3	2x Cat5e 0.15m red
Bow-2000 # 1 Sync-Link ports 6-7	Bow-2000 # 2 Sync-Link ports 2-3	2x Cat5e 0.15m red

The figure below shows the Bow-2000 Sync-Link cabling for a Bow Pod₁₆ DA system.

Fig. 4.36 Bow Pod₁₆ DA system (Sync-Links)

4.3.3. Bow-2000 to Bow-2000 management cabling (Cat5e)

Note

This step is only required for Bow Pod₁₆ DA systems.

There are 2 Cat5e management ports in the middle of each Bow-2000.

Fig. 4.37 Bow-2000 Cat5e management ports

Using 0.3m blue Ethernet Cat5e cables, link the top management port (2) of each Bow-2000 to the bottom management port (1) of the Bow-2000 that is installed directly above (see Table 4.3 and Fig. 4.38). The top management port (2) of the top-most Bow-2000 (#4) and the bottom management port (1) of the bottom-most Bow-2000 (#1), are left unconnected.

Table 4.3 Bow-2000 management port mapping

From Bow-2000 management connections	To Bow-2000 management connections	Cables
Bow-2000 # 3 management ports 2	Bow-2000 # 4 management ports 1	Cat5e 0.3m blue
Bow-2000 # 2 management ports 2	Bow-2000 # 3 management ports 1	Cat5e 0.3m blue
Bow-2000 # 1 management ports 2	Bow-2000 # 2 management ports 1	Cat5e 0.3m blue

The figure below shows the Bow-2000 management cabling for a Bow Pod₁₆ DA system.

Fig. 4.38 Bow Pod₁₆ DA system (Bow-2000 management cabling)

4.3.4. Bow-2000 to server management cabling (Cat5e)

Note

This step is required for all Bow Pod DA systems.

There are 2 Cat5e management ports in the middle of each Bow-2000.

Fig. 4.39 Bow-2000 Cat5e management ports

Using a 1.5m blue Ethernet Cat5e cable, link the top management port (port #2) of the top Bow-2000 to management port #1 of the R6525 server, as given in Table 4.4.

Table 4.4 Bow-2000 management port mapping

From Bow-2000 management connection	To server management connection	Cables
Top Bow-2000 management port 2	R6525 server management port 1	Cat5e 1.5m blue

Fig. 4.40 and Fig. 4.41 show the Bow-2000 to server management cabling for a single Bow-2000 and a Bow Pod₁₆ DA system respectively.

Fig. 4.40 Single Bow-2000 DA system (Bow-2000 to server management cabling)

Fig. 4.41 Bow Pod₁₆ DA system (Bow-2000 to server management cabling)

4.3.5. Bow-2000 to server data cabling (QSFP)

Note

This step is required for all Bow Pod DA DA systems.

There are two QSFP RNIC data ports on the left of each Bow-2000.

Fig. 4.42 Bow-2000 RNIC ports

Only one of these (port #2) should be connected from each Bow-2000 to the server with 1.5m QSFP cables, as shown in Table 4.5. In a single Bow-2000 DA system, only Bow-2000 #1 is present.

Table 4.5 Bow-2000 RNIC port mapping

Bow-2000 RNIC port	Server port	Cables
Bow-2000 # 4 port 2	Server NIC slot 2, port 2	QSFP 1.5m
Bow-2000 # 3 port 2	Server NIC slot 2, port 1	QSFP 1.5m
Bow-2000 # 2 port 2	Server NIC slot 3, port 2	QSFP 1.5m
Bow-2000 # 1 port 2	Server NIC slot 3, port 1	QSFP 1.5m

Fig. 4.43 and Fig. 4.44 show the Bow-2000 data cabling for single Bow-2000 and Bow Pod₁₆ DA systems, respectively.

Fig. 4.43 Single Bow-2000 DA system (Bow-2000 data cabling)

Fig. 4.44 Bow Pod₁₆ DA system (Bow-2000 data cabling)

Note

Bow-2000 #1 (the lowest in the stack) is always connected to Port 1 in server slot 3.

4.4. Power cabling

The method for cabling the PDUs will depend on the choice of PDU type and location. Each Bow-2000 has two power inputs and these should be supplied from separate power distribution units for redundancy.

4.5. Completing the rack

The following steps describe completing the rack: fitting blanking panels and re-installing the doors and side panels, if required.

4.5.1. Blanking panels

For proper airflow, we recommended installing 1U blanking panels in every unoccupied rack slot at the front of the rack.

Fig. 4.45 1U blanking panels

4.5.2. Rack completion

Re-install the front and rear doors. Ensure the earth cables are reconnected to the cable on the rack. Re-install the top and bottom side panels on each side of the rack.