简介 linux Container是OS级别的虚拟化方案,它相比于一般的虚拟机没有了硬件模拟以及指令模拟,相比传统虚拟机具有更低的开销,因此可以应用到私有云之中。LXC目前的版本支持对memory,cpu以及block io的管理和限制,目前不支持对网络io的管理,但该特性已经加入到其roadmap,这些资源的管理和限制对企业私有云的搭建份至关重要,可以提高集群资源的使用率。 环境 LXC需要比较高版本的内核支持,28以上,最好是32以上。我的测试...
原帖地址 http://www.killdb.com/?p=390 什么是os block header?它有哪些作用?如果它损害了怎么办? 下面是关于os block header的解释,来自MOS。 The OS block Header is in the first datafile block. It is used by Oracle to store Operating System information. It is the block Zero. It is not the datafile header which is in Oracle block 1. Corruption in block Zero will not cause damage to the data and it...
The analysis of cfq for linux 2.6.28.5 How to add request: Instruction: (1)(2)(5): Every process in cfq has a correspond queue whose name is cfqq. Actually, each cfqq has two queues, like DEADLINE, one queue is sorted by LBA of requests, the other queue is sorted by arrival time. The queue sorted by LBA is actually a red-black tree while the queue sorted by arrival time is calle...
[code][ssh@Nick sdb]$ stat a16 File: `a16' Size: 0 blocks: 2 io block: 1024 regular empty file Device: 815h/2069dInode: 32128 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 501/ ssh) Gid: ( 500/ nick) Access: 2013-06-25 16:29:42.000000000 +0800 Modify: 2013-06-25 16:29:42.000000000 +0800 Change: 2013-06-25 16:29:42.000000000 +0800[/code]不好意思,请问个问题。究竟...
引自[http://blog.ccw.com.cn/blog.php?do-showone-uid-171569-itemid-46404-type-blog-type-blog.html] 由于粘过来的时候有很多乱码,所以仅做个连接 本文来自ChinaUnix博客,如果查看原文请点:http://blog.chinaunix.net/u2/73874/showart_1422043.html
本帖最后由 remaper 于 2013-05-23 12:25 编辑 我大致的把block/下的代码都看了,实在没想明白是怎么一回事。 kernel版本:3.9 首先我理想中的block io层是这样的,对上层只提供submit_bio接口,将bio添加到request_queue里,然后后台会有thread,不断的从request_queue里将request取出来,dispatch给驱动去处理。 但是实际上有两个问题不是很清楚: 1、只看到初始化的时候,创建了一个kblockd_workqueue,对每个塞进来的wor...
标准I/O库提供缓冲的目的是尽可能地减少使用read和write调用的次数。他也对每个I/O流自动地进行缓冲管理,从而避免了应用程序需要考虑这一点所带来的麻烦。不幸的是,标准I/O库最令人迷惑的也是他的缓冲。 标准I/O提供了三种类型的缓冲: [color="#000000"]1、全缓冲。这种情况下,在填满标准I/O缓冲区后才进行实际I/O操作。对于驻留在磁盘上的文件通常是由标准I/O库实施全缓冲。一个流上执行第一次I/O操作时,相关标准I/O函...
[root@waptx63 ~]# tune2fs -l /dev/sda9 |grep "block size" block size: 4096 本文来自ChinaUnix博客,如果查看原文请点:http://blog.chinaunix.net/u1/38871/showart_1922002.html
linux: The Journaling block Device June 21, 2006 - 2:40am Submitted by Kedar Sovani --> Submitted by Kedar Sovani on June 21, 2006 - 2:40am. Atomicity is a property of an operation either to succeed or fail completely. Disks assure atomicity at the sector level. This means that a write to a sector either goes through completely or not at a...