关于HP MSA500G2与SA642卡的问题

老硬盘

请教各位，642是SCSI卡还是RAID卡？
MSA500G2的RAID功能到底是由G2 控制器实现还是由642RAID卡实现呢？
百思不得其解

lsw

642是RAID卡
MSA500G2没有控制器，所以需要有块RAID卡。

crazygod

The MSA500 G2 controller (Figure 2) is a hot-pluggable and intelligent Redundant Array of Independent Disks (RAID) controller with integrated status indicators and a 256-megabyte read/write battery-backed cache expandable to 512 megabytes (per controller). One controller ships standard with the HP MSA500 G2 system; a redundant controller is optional. The MSA500 G2 controller is built upon a 32-bit superscalar, reduced instruction set computing (RISC) processor and features a high performance RAID coprocessor designed by HP to enhance performance of RAID parity write operations for RAID 5 and Advanced Data Guarding (ADG).
The MSA500 G2 controller features battery-backed write cache to protect posted-write data in the event that external power to the system is interrupted, a host computer fails, or the controller itself fails. The write cache can protect data for up to three days. In a system with a single MSA500 G2 controller, if the controller fails, the cache module can be removed and installed on a replacement controller (within three days with no loss of data), and the posted-write data will be flushed. The write cache can protect data for up to three days. Redundant, maintenance-free nickel metal hydride batteries are used on the battery-backed cache to improve reliability.
In clusters with non-intelligent enclosures or “just a bunch of drives” (JBOD), the RAID controllers are located in each of the clustered servers. Unlike the MSA500 G2 system design, these controllers are not synchronized and have no mechanism to keep cache data coherent. Unsynchronized controllers cannot implement write-caching, the lack of which seriously degrades the performance of the JBOD cluster.

从以上描述感觉就是RAID控制器

ipod

642是阵列卡，MSA500G2也有阵列控制器。
MSA500G2的RAID功能是自身的控制器实现的。642在这里面起的是联结作用，也就是当成SCSI卡使用。

crazygod

Product Description        Smart Array 642 2ch U320 Pci-x 64mb Cache 68pin Controller       
Device Type         Storage controller (RAID) - plug-in card        
Interface(s) Required         PCI-X / 133 MHz        
Controller Interface Type         Ultra320 SCSI        
Data Transfer Rate         320 MBps        
Buffer Size         64 MB (installed) / 128 MB (max)        
Supported Devices         Hard drive        
Channel Qty         2        
Max Storage Devices Qty         20        
RAID Level         RAID 0, RAID 1, RAID 5, RAID 10        

642到底是RAID卡还是SCSI卡，它支持RAID。如果要是SCSI卡，那么MSA500不一定要和642配合吧，我随便买个SCSI卡能用吗？

ipod

msa500g2必须用642或者6i的卡连接，这是固定搭配，其他的scsi卡不行 。

daniel_w

是的，HP的就这毛病，以前的要求用532，一样的道理。

noise

原帖由 "lsw" 发表：
642是RAID卡
MSA500G2没有控制器，所以需要有块RAID卡。

这说法还真是第一次听说，MSA500G2是有独立的RAID控制器的，642在与MSA500G2连接的时候只是一个连通设备，并没有使用它的RAID功能，最明显的，642没有ADG更能，而MSA500却有。

其实连接MSA500G2的连通设备还有6I。

不过HP的这种捆绑应该是对自己产品的一种保护吧，我看感觉别扭，可没办法，我们只是使用这。如果不配集群连的服务器又有6I的话可以省下642。

wee0618

用642卡有什么不好？你要是找一块u320的scsi卡来做连接的话（抛开兼容性问题）恐怕造价还要高

gzl332

MSA500G2 标配有一个带256M电池保护缓存的控制器,而且可以升级到512M 还可以升级到双控制器的;

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