Ulimit

Overview

Ulimit에 대한 기술 문서입니다.

Summary

• 무엇인가? - Ulimit
• 왜 필요한가? - HPC 및 서버 환경에서 필수 개념
• 언제 사용하는가? - 서버 구성, 성능 튜닝, 문제 해결 시

Purpose

이 문서가 존재하는 이유

• Goal: Ulimit에 대한 기술 정보 제공
• Scope: Ulimit의 개념, 사용법, 설정
• Non-goals: 다른 주제로의 확장

Key Concepts

Concept	Description	Related
Ulimit	HPC/서버 환경에서 중요한 기술 개념	Linux, Server

Detailed Explanation

ulimit is a built-in Linux shell command that allows viewing or limiting system resource amounts that individual users consume. Limiting resource usage is valuable in environments with multiple users and system performance issues. /etc/security/limits.conf file is a configuration file that defines the system resource allocation settings ulimit uses. Changing the values in the file persist after system reboot. To specify the type with ulimit, we use -H (hard) and -S (soft), where -H sets hard limits, while -S sets soft limits. By default, without either flag, -S is presumed The soft limit is manageable by any user, and its maximum value cannot exceed the hard limit. The hard limit acts as a ceiling for the soft limit. ulimit -Sa The hard resource limit defines physical resource limit for a user. At the same time, the hard limit is the maximum value for soft limit. Only root users are allowed to change the hard limit. ulimit -Ha The ulimit command takes the following general syntax ulimit [flags][limit]

Flag	Effect to	Description
-H		The hard limit for the given resource. Only root users can raise the hard limit, and any process can lower it.
-S	Best Practices 최신 버전 사용 권장 공식 문서 참고 테스트 환경에서 먼저 검증 References Ulimit Related Pages Linux Server Hardware Network Knowledge Graph Related → Linux → Linux Kernel Tuning → THP (Transparent Huge Pages) → Sar → Vmstat