Complete Mellanox / InfiniBand keyboard shortcuts and commands reference — 19 shortcuts across 3 categories. Quick reference cheat sheet for Windows & Mac.
InfiniBand fabrics from NVIDIA (formerly Mellanox) are diagnosed with a set of small tools that ship with the OFED drivers, and this page groups them by question: is the port up, is the link at the right speed, can this node reach that one at full bandwidth, and what firmware is the card running. The notes follow that order, which is also the order to run them in when a GPU cluster's collective operations are slow.
| Shortcut | Action | Description |
|---|---|---|
| ibstat | Port status | Check detailed IB HCA port status. |
| ibstatus | Status summary | Summarize all IB port status. |
| ibv_devinfo | Device info | Show detailed IB device information. |
| iblinkinfo | Link info | Show all link status in the subnet. |
| ibhosts | List hosts | List all IB hosts in the subnet. |
| ibswitches | List switches | List all IB switches in the subnet. |
| perfquery | Perf counters | Query port performance counters. |
| smpquery portinfo [LID] [port] | Port detail | Query SMP info for specific port. |
| Shortcut | Action | Description |
|---|---|---|
| ib_write_bw | Write bandwidth test | Measure RDMA Write bandwidth. |
| ib_read_bw | Read bandwidth test | Measure RDMA Read bandwidth. |
| ib_send_lat | Send latency test | Measure RDMA Send latency. |
| ibping [LID] | IB ping | Ping test InfiniBand connection. |
| opensm | Subnet manager | Start OpenSM subnet manager. |
| mlnx_tune | Performance tuning | Auto-tune Mellanox NIC performance. |
| Shortcut | Action | Description |
|---|---|---|
| mst start | Start MST | Start Mellanox Software Tools driver. |
| mst status | MST status | Check MST device status. |
| mlxconfig -d [dev] query | Query NIC config | Query NIC configuration. |
| flint -d [dev] query | Check firmware | Check NIC firmware version. |
| mlxfwmanager | Firmware manager | Manage and update Mellanox firmware. |
The most essential Mellanox / InfiniBand shortcuts are: ibstat (Port status), ibstatus (Status summary), ibv_devinfo (Device info).
These are command-line commands — type them in your terminal or console. Combine them with shell history search (Ctrl + R) and aliases to work even faster.
The Mellanox / InfiniBand shortcut for port status is ibstat. Check detailed IB HCA port status.
Yes — use My Stack to combine Mellanox / InfiniBand shortcuts with any other platform on this site into one printable reference, which is useful if your daily workflow spans several tools.
ibstat prints each HCA port with its state (Active, Down, Initializing), rate and LID; a port stuck in Initializing means no subnet manager has configured it. ibstatus is the one-line-per-port summary and ibv_devinfo the verbose device view, including firmware version and link layer (InfiniBand or Ethernet for RoCE). iblinkinfo walks the fabric and prints every link with its speed and width, which is how a cable negotiated down to a lower rate is found. ibhosts and ibswitches list what the subnet manager sees, and opensm is the subnet manager itself, which must run somewhere on the fabric for ports to become Active.
ib_write_bw and ib_read_bw measure RDMA bandwidth between two nodes — run the server side with no argument and the client with the server's hostname — and ib_send_lat measures latency; results well below the link rate point to a slow link, a wrong PCIe slot or a CPU affinity problem. ibping [LID] checks reachability by LID and perfquery reads a port's error counters (symbol errors, link downed, receive errors), the first place to look when bandwidth tests are inconsistent. smpquery portinfo [LID] [port] queries a specific switch port. mlnx_tune applies the recommended OS and NIC tuning profile.
mst start loads the tools driver and mst status lists device paths, which the other commands take as -d. mlxconfig -d [dev] query shows NIC configuration such as link type (IB or Ethernet), SR-IOV and the number of VFs — the command for switching a ConnectX card between InfiniBand and Ethernet modes. flint -d [dev] query reports the firmware version and PSID, and mlxfwmanager updates firmware for every card in the machine, which cluster operators do fleet-wide before a driver upgrade.
Open your assistant with this page preloaded as the source — great for follow-up questions like "which of these work in other apps?"