免费注册 查看新帖 |

Chinaunix

  平台 论坛 博客 文库
最近访问板块 发新帖
查看: 2074 | 回复: 0

DS6000的RANK概念 [复制链接]

论坛徽章:
0
发表于 2009-07-22 11:13 |显示全部楼层
IBM DS6000存储具备高端存储的特性和功能,但是性能却处在高端产品之下。在DS6000中IBM引入了RANK的逻辑概念,在DS6000中还有其他的新的逻辑概念(相对容易理解),以下是从redbook中看到的一段:
The available space on each rank is divided into extents. The extents are the building blocks of the logical volumes. An extent is striped across all disks of an array as shown in Figure 4-4 on page 71 and indicated by the small squares in Figure 4-5 on page 72.The process of forming a rank does two things: The array is defined for either fixed block (open systems) or CKD (System z) data. This determines the size of the set of data contained on one disk within a stripe on the array. The capacity of the array is subdivided into equal sized partitions, called extents. The extent size depends on the extent type, FB or CKD.
For open systems, an FB rank has an extent size of 1 GB (where 1 GB equals 230 bytes).For the System z environment, storage capacity is defined in units of 3390 volume sizes. A3390 Model 3 is three times the size of a Model 1, and a Model 1 has 1113 cylinders, which is about 0.94 GB. The extent size of a CKD rank therefore was chosen to be one 3390 Model 1, or 1113 cylinders.One extent is the minimum physical allocation unit when a LUN or CKD volume is created, as we discuss later. It is still possible to define a CKD volume with a capacity that is an integral multiple of one cylinder or a fixed block LUN with a capacity that is an integral multiple of 128 logical blocks (64K bytes). However, if the defined capacity is not an integral multiple of the capacity of one extent, the unused capacity in the last extent is wasted. For instance, you could define a 1 cylinder CKD volume, but 1113 cylinders (1 extent) is allocated and 1112 cylinders would be wasted.Figure 4-4 shows an example of an array that is formatted for FB data with 1 GB extents (the squares in the rank just indicate that the extent is composed of several blocks from different DDMs).

在实际的使用绝大多数时候RANK与ARRAY还是一对一的关系,其中的FB类型的extent大小为1G,而extent是其所在ARRAY中多有磁盘的strip上的,也隐含的说出了,extent大小=ARRAY中磁盘个数*strip深度。extent大小固定后,磁盘的个数就决定了该array的性能。
               
               
               
               

本文来自ChinaUnix博客,如果查看原文请点:http://blog.chinaunix.net/u3/99967/showart_2003182.html
您需要登录后才可以回帖 登录 | 注册

本版积分规则 发表回复

  

北京盛拓优讯信息技术有限公司. 版权所有 京ICP备16024965号-6 北京市公安局海淀分局网监中心备案编号:11010802020122 niuxiaotong@pcpop.com 17352615567
未成年举报专区
中国互联网协会会员  联系我们:huangweiwei@itpub.net
感谢所有关心和支持过ChinaUnix的朋友们 转载本站内容请注明原作者名及出处

清除 Cookies - ChinaUnix - Archiver - WAP - TOP