Merging upstream version 1.44.3.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/health/guides/net/10min_fifo_errors.md b/health/guides/net/10min_fifo_errors.md
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+### Understand the alert
+
+Between the IP stack and the Network Interface Controller (NIC) lies the driver queue. This queue is typically implemented as a FIFO ring buffer into the memory space allocated by the driver. The NIC receive frames and place them into memory as skb_buff data structures (SocKet Buffer). We can have queues (ingress queues) and transmitted (egress queues) but these queues do not contain any actual packet data. Each queue has a pointer to the devices associated with it, and to the skb_buff data structures that store the ingress/egress packets. The number of frames this queue can handle is limited. Queues fill up when an interface receives packets faster than kernel can process them.
+
+Netdata monitors the number of FIFO errors (number of times an overflow occurs in the ring buffer) for a specific network interface in the last 10 minutes. This alarm is triggered when the NIC is not able to handle the peak load of incoming/outgoing packets with the current ring buffer size.
+
+Not all NICs support FIFO queue operations.
+
+### More about SKB
+
+The SocKet Buffer (SKB), is the most fundamental data structure in the Linux networking code. Every packet sent or received is handled using this data structure. This is a large struct containing all the control information required for the packet (datagram, cell, etc).
+
+The struct sk_buff has the following fields to point to the specific network layer headers:
+
+- transport_header (previously called h) – This field points to layer 4, the transport layer (and can include tcp header or udp header or
+  icmp header, and more)
+
+- network_header (previously called nh) – This field points to layer 3, the network layer (and can include ip header or ipv6 header or arp
+  header).
+
+- mac_header (previously called mac) –  This field points to layer 2, the link layer.
+
+- skb_network_header(skb), skb_transport_header(skb) and skb_mac_header(skb) - These return pointer to the header.
+
+### Troubleshoot the alert
+
+- Update the ring buffer size
+
+1. To view the maximum RX ring buffer size:
+
+   ```
+   ethtool -g enp1s0
+   ```
+
+2. If the values in the Pre-set maximums section are higher than in the Current hardware settings section, increase RX (or TX) ring buffer:
+
+   ```
+   enp1s0 rx 4080
+   ```
+
+3. Verify the change to make sure that you no longer receive the alarm when running the same workload. To make this permanently, you must consult your distribution guides.
+