Linux的缓存cache释放

优快云 博客示例
本文提供了一个优快云博客的示例链接,虽然具体内容未直接给出,但通常涉及软件开发和技术分享等方面的内容。
http://blog.youkuaiyun.com/u014740338/article/details/66975550地址
<think> Hmm, the user is asking about methods to release cache in Linux systems. Looking at the references they provided, it's clear they've already found some technical commands but want a comprehensive understanding. The references mention using echo commands to write to /proc/sys/vm/drop_caches with values 1,2,3. References [1] and [2] both show this approach but [1] gives more context about what each value does while [2] is more concise. I notice the user specifically says "release cache" but technically in Linux we're talking about freeing up memory used by disk buffers (buff) and page cache (cache). The distinction matters because: - Buffers (buff) hold metadata about files/directories - Page cache (cache) stores actual file contents The safest method is starting with echo 1 which only clears page cache. Echo 3 is more aggressive and should be used with caution. The user might be experiencing high memory usage showing as buff/cache in free command output. They probably want to free this memory without rebooting. Important caveats to mention: - This doesn't harm running applications - Kernel will repopulate caches as needed - root privileges required For completeness, I should also mention the sync command option before clearing caches to flush unwritten data to disk. While not strictly necessary, it's good practice. The user seems technical since they're using root commands, so I can include the detailed explanations about what each echo value does. They'll appreciate understanding the underlying mechanism rather than just commands. </think> 在Linux系统中释放缓冲(buff)和缓存(cache)内存,主要可通过以下方法实现: ### 一、手动释放缓存(推荐方法) 执行三条核心命令,需**root权限**: ```bash # 1. 先同步文件系统(确保数据安全) sync # 2. 清除页缓存(PageCache) echo 1 > /proc/sys/vm/drop_caches # 3. 清除目录项和inode缓存 echo 2 > /proc/sys/vm/drop_caches # 4. 同时清除页缓存和inode缓存 echo 3 > /proc/sys/vm/drop_caches ``` **效果验证**: ```bash free -h # 查看内存变化 total used free shared buff/cache available Mem: 7.6G 627M 6.9G 15M 121M 6.8G ``` ### 二、内核参数自动控制 修改`/etc/sysctl.conf`实现自动回收: ```bash # 添加以下参数 vm.vfs_cache_pressure=100 # 提高inode缓存回收优先级(默认100) vm.swappiness=10 # 降低交换分区使用倾向(建议值) ``` 生效配置: ```bash sysctl -p ``` ### 注意事项 1. **操作影响**: - `echo 1`:仅清理文件页缓存,**最安全** - `echo 3`:清除所有缓存,可能导致短暂I/O上升 - 生产环境建议夜间执行 2. **内存机制**: - Buffers:内核块设备缓冲区 - Cache:文件系统页缓存 - Linux自动回收空闲缓存,**手动清理仅用于特殊场景**[^1]
评论
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值