# Sre
All Sre notes →1 — Linux Internals Every SRE Must Know
The kernel-level mental model — syscalls, the VFS, the scheduler — that turns 'the server is slow' from a guess into a diagnosable claim.
10 — gRPC
Why internal service-to-service calls increasingly run on gRPC instead of REST, and the deadline propagation and streaming semantics that change how you debug a slow call chain.
11 — TLS and Certificates
The handshake, cipher negotiation, and certificate chain validation that fail silently until an expiry takes down a service nobody remembered depended on it.
12 — Load Balancers
L4 vs L7 load balancing, health check design, and why a load balancer's own failure mode is often the single biggest blast radius in the stack.
13 — Reverse Proxies
What a reverse proxy actually buys you — TLS termination, routing, buffering — and the latency and failure modes it adds in exchange.
14 — CDNs
Cache hit ratio as a reliability metric, not just a cost one, and what happens to origin load the moment a CDN's cache goes cold.
15 — Linux Troubleshooting
The strace/perf//proc-level toolkit for answering 'why is this box actually doing that' when the metrics dashboard has run out of answers.
2 — Processes, Threads and Scheduling
How the Linux scheduler decides what runs next, and why CPU throttling in a container often has nothing to do with raw CPU usage.
3 — Memory Management
Virtual memory, paging, and the OOM killer — why 'out of memory' in Kubernetes is rarely about the number top reports.
4 — Filesystems and Storage
How filesystems, page cache, and I/O schedulers interact to turn a disk-bound service's latency graph into something explainable.
5 — TCP/IP Deep Dive
How TCP's handshake, flow control, and congestion control actually behave under production load, and what that means when 'the network is slow' shows up in an incident.
6 — DNS
Why DNS is the failure mode that takes down services that have nothing to do with DNS, and the resolution chain an SRE needs to trace under pressure.
7 — HTTP/1.1
The request/response semantics, keep-alive, and head-of-line blocking behavior that still underpin most production traffic today.
8 — HTTP/2
Multiplexing, stream prioritization, and header compression — what HTTP/2 actually fixed from HTTP/1.1, and the new failure modes it introduced.
9 — HTTP/3
Why HTTP/3 moved off TCP entirely, and what QUIC changes about how connection loss and retransmission show up in your latency metrics.