vm.vfs_cache_pressure controls how aggressively the kernel reclaims dentry and inode caches relative to page cache. Most tuning guides set it to 50 or 200 without explaining what it actually changes….
Read MoreLinux Socket Memory Tuning on a VPS: tcp_mem, tcp_wmem and the Overcommit Trap
Every byte the kernel buffers for TCP has to come from somewhere. On a VPS with a fixed RAM ceiling, socket buffers compete directly with your application, your page cache,…
Read MoreDiagnosing CPU Thermal Throttling and Frequency Scaling on a VPS: A Measurement Method
A VPS that benchmarks well on a fresh boot and degrades over a long run has a specific class of cause: the CPU is not running at the frequency you…
Read MoreTuning CFS on a VPS: When Low Wakeup Latency Beats Raw Throughput
Most VPS performance advice tells you to crank values that improve throughput. That is the wrong default for interactive services. A scheduler tuned for maximum batch throughput will happily let…
Read MorePostgreSQL Autovacuum Tuning on a Small VPS: Preventing Bloat Without Starving I/O
Autovacuum is the most misunderstood background process on a small PostgreSQL VPS. Left at defaults sized for large dedicated servers, it either runs too rarely — letting dead tuples bloat…
Read Morebtrfs zstd vs ext4 on a Small VPS: Real Compression Benchmarks
Filesystem-level compression sounds like free disk space, and on a small VPS with a 25-40 GB root volume it often is. The catch is CPU cost and the write-amplification that…
Read MoreTuning Linux Swap on an NVMe VPS Without Causing Latency Spikes
Swap has a bad reputation on servers, and mostly for good reason: if a workload actively pages to a slow disk, latency explodes. But swap is not inherently harmful. On…
Read MoreEnforcing Disk I/O QoS with cgroup v2 io.latency and io.max on Noisy Instances
Stop one runaway process from starving everything else on the disk. Use io.latency target-latency control and io.max bandwidth caps to enforce per-workload disk QoS on cgroup v2.
Read MoreKernel CPU Vulnerability Mitigations: Measuring Their Real Performance Cost on VPS Workloads
Spectre, Meltdown, and MDS mitigations cut throughput on some workloads and barely touch others. Measure the actual cost on your instance across syscall-heavy, network, and cryptographic paths.
Read Morezram vs Swap Partition on a VPS: Latency, Memory Savings and When Each One Hurts
On a VPS you cannot add physical RAM, so when memory pressure arrives you have two broad escapes: spill to disk-backed swap, or compress cold pages in RAM with zram….
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