HADOOP-HDFS 自动驱除Trash以释放空间

HADOOP-HDFS 自动清除Trash以释放空间
HDFS should support Auto-Emptier to automatically expunge trash for releasing space.

HADOOP-HDFS需要有一个Auto-Emptier 线程来自动清除trash, 以释放HDFS的总使用空间, 该功能可以配置为可选项, 可以在Configuration下增加这两个参数以供配置.

1.fs.trash.autoemptier.interval  执行空间检查的时间时间隔, 设置为0时, 禁用该功能, 默认为20 Seconds.
2.fs.trash.max.percentused 当已使用空间率大于该值, 执行回收以释放空间. 默认为0.8f

这个功能只是个人的倾向而已, 并没有新建Feature到Apache, 欢迎同志们拍砖.

float percent = namenode.namesystem.getCapacityUsedPercent();if(percent < 1 && percent >= maxPercentUsed) {Path path = new Path(fs.getHomeDirectory(), TRASH);/*Trash trash = new Trash(path, conf);trash.expunge();trash.checkpoint();*/long space = 0;if (!fs.exists(path)|| (space = fs.getFileStatus(path).getLen()) == 0) {continue;}if(!fs.delete(path, true)){LOG.warn("Failed to expunge trash for releasing space.");} else {LOG.info("Auto-emptier, expunge trash for releasing space: " + FsShell.byteDesc(space));}}

由于博客标题长度的限制, 标题里开头少写了HDFS字样. 源码见于附件. if (!fs.exists(path)|| (space = fs.getContentSummary(path).getLength()) == 0) {continue;}if (namenode.namesystem.getFSState().equals("Operational") && now >= end) {long used = namenode.namesystem.getCapacityUsed();long remaining = namenode.namesystem.getCapacityRemaining();long presentCapacity = used + remaining;String pc = FsShell.limitDecimalTo2(((1.0 * used) / presentCapacity) * 100);float percent = Float.valueOf(pc)/100f;LOG.info("Present dfs used: " + percent);if(percent < 1 && percent >= maxPercentUsed) {Path path = new Path(fs.getHomeDirectory(), TRASH);long space = 0;if (!fs.exists(path)|| (space = fs.getContentSummary(path).getLength()) == 0) {continue;}if(!fs.delete(path, true)) {LOG.warn("Failed to expunge trash for releasing space.");} else {LOG.info("Auto-emptier, expunge trash for releasing space: " + FsShell.byteDesc(space));}}}

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