Create the guid.txt File

If your InfiniBand fabric uses the Fat-Tree routing algorithm, you must provide a modified listing of fabric card GUIDs, called the root node GUID file, for the Subnet Manager. The /etc/opensm/guid.txt file is such a file. This procedure describes how to create the guid.txt file.

1. Type the following command on the CMC to retrieve the fabric card base GUID:

   # getbaseguid fc slot

   where slot is the number of the fabric card (0–8). For example:

   # getbaseguid fc 0
   Base GUID = 0x00bad0fc0009f000
   #

2. Record the GUID to a text editor on your Linux InfiniBand host.
3. Repeat Step 1 and Step 2 for each fabric card.

   Once you have recorded each fabric card’s GUID, you will have a list similar to the following on your Linux InfiniBand host:

   0x00bad0fc0009f000
   0x00bad0fc0033f100
   0x00bad00017fcf200
   0x00bad00005fcf300
   0x00bad00003fcf400
   0x00bad00007fcf500
   0x00bad0fc0011f600
   0x00bad0b00002f700
   0x00bad0b00001f800

   ---

   Note - If you have fewer than 9 fabric cards, your list will be smaller.

   ---

4. For each GUID, add the following values to make two new sums:

   • 0xa2

   • 0xb2

   ---

   Note - For GUIDs that end with two zeros (00), you are effectively replacing the zeros with a2 and b2.

   ---

   For example, 0x00bad0fc0009f000 becomes:

   • 0x00bad0fc0009f0a2

   • 0x00bad0fc0009f0b2

5. Repopulate your list with the modified GUIDs.

   For example:

   0x00bad0fc0009f0a2
   0x00bad0fc0009f0b2
   0x00bad0fc0033f1a2
   0x00bad0fc0033f1b2
   0x00bad00017fcf2a2
   0x00bad00017fcf2b2
   0x00bad00005fcf3a2
   0x00bad00005fcf3b2
   0x00bad00003fcf4a2
   0x00bad00003fcf4b2
   0x00bad00007fcf5a2
   0x00bad00007fcf5b2
   0x00bad0fc0011f6a2
   0x00bad0fc0011f6b2
   0x00bad0b00002f7a2
   0x00bad0b00002f7b2
   0x00bad0b00001f8a2
   0x00bad0b00001f8b2

6. Save the list on the Linux InfiniBand host as the /etc/opensm/guid.txt file.
7. Set the permissions for the /etc/opensm/guid.txt file:

   # chmod 0644 /etc/opensm/guid.txt
   #

Related Information

• Switch Command Reference, getbaseguid command

• Switch Command Reference, opensm command

• Create the opensm.conf File

• Start the Subnet Manager With Fat Tree Routing