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Q&A
Q&AInodes may be exhausted, or deleted files may still be held open by running processes.
Compare df -h with df -i. If block usage and directory totals disagree, inspect open-but-deleted files with lsof +L1. A process retains allocated blocks until it closes the file; restart or signal the owning service through its safe lifecycle after confirming the file is disposable.
Q&A
Q&AThey express different reachability and cleanup relationships, but are not general-purpose cache policies.
Weak references do not keep an object alive and are useful in structures such as canonicalizing maps when carefully designed. Soft references may be cleared under memory pressure, but their timing is not a predictable cache eviction policy. Phantom references support post-mortem cleanup coordination through a reference queue; they do not let code retrieve the referent.
devops
8 minBuild an operational view around user-visible latency, traffic, errors, and saturation instead of dashboards full of disconnected metrics.
unix
7 minFollow signals from a container stop through shell wrappers and child processes, and build shutdown behavior that preserves work.
unix
8 minUnix is full of tiny control primitives. Learn how `set -o pipefail`, process signals, and clean lifecycle management keep shell pipelines reliable and debuggable.
kubernetes
8 minFollow deletion timestamps and controller-owned finalizer removal without hiding leaked resources.
Q&A
Q&AWindow values are computed after WHERE in logical query processing.
WHERE filters source rows before window calculations are available. Put the window expression in a common table expression or derived table, then filter its rank in the outer query. This also makes the ranking input set explicit.
Q&A
Q&AInspect local socket state and bind address before changing firewall policy.
On Linux, `ss -lntup` lists listening sockets; `netstat` may be available via net-tools on older systems. Confirm the process, address, and network namespace. A service bound only to 127.0.0.1 is not externally reachable; also check container port mapping and host policy.