Most backup failures are not discovered during the outage — they are discovered during the restore, when it is far too late. A backup job that exits zero every night…
Read MoreDiagnosing DNS Resolver Latency on a VPS with dig and tcpdump
DNS resolution latency is invisible until it is not. A resolver that answers in 5 ms and one that answers in 2 seconds produce identical application code and wildly different…
Read MoreEphemeral Port Exhaustion and SO_REUSEPORT Tuning on Linux Servers
When a busy server starts refusing new connections but traffic and CPU look normal, the cause is often a quiet resource limit: the ephemeral port range, or the loading of…
Read MoreTuning net.ipv4.tcp_rmem for High-Latency VPS Workloads: Buffer Sizing by Bandwidth-Delay Product
The default 6 MB TCP receive-buffer ceiling caps single-stream throughput on high-RTT links. Measure the bandwidth-delay product, size tcp_rmem and core.rmem_max correctly, and verify with live socket statistics.
Read MoreFinding Packet Loss on a VPS Uplink with tcpdump, nstat, and eBPF Drop Tracing
Map packet-loss symptoms to the layer that caused them using kernel counters, targeted tcpdump captures, and eBPF kfree_skb reason codes. Includes a counter-to-cause reference table.
Read MoreConntrack Table Exhaustion on a VPS: Measuring nf_conntrack Before Connections Drop
Measure nf_conntrack_count against nf_conntrack_max, then size the table and timeouts from real traffic. Includes a per-workload entry-consumption table and a post-change regression check.
Read MoreRaising File Descriptor and Process Limits on a VPS for High Connection Counts
Most services on a VPS have a hard ceiling that has nothing to do with CPU, RAM, or bandwidth: the number of open file descriptors and processes they are permitted….
Read MoreCapping Memory with cgroups v2 on an Oversubscribed VPS
Hard and soft memory ceilings per service with cgroups v2 on Debian/Ubuntu VPS, plus a worked allocation plan for a 1 GB instance.
Read MoreReading Linux PSI (Pressure Stall Information) to Diagnose VPS Bottlenecks
How to read /proc/pressure for cpu, memory and io to find real VPS bottlenecks that utilisation graphs hide.
Read MorePHP 8.4 vs 8.3 on a VPS: OPcache, JIT, and Real Throughput Benchmarks
PHP 8.4 shipped in November 2024 and is now the default on Ubuntu 24.04 repositories and most 2026 managed images. The question for anyone running a small VPS is concrete:…
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