软件raid：只能通过Linux系统本身来查看
cat /proc/mdstat
可以看到raid级别，状态等信息。
硬件raid： 最佳的办法是通过已安装的raid厂商的管理工具来查看，有cmdline，也有图形界面。如Adaptec公司的硬件卡就可以通过下面的命令进行查看：
# /usr/dpt/raidutil -L all
可以看到非常详细的信息。
当然更多情况是没有安装相应的管理工具，只能依靠Linux本身的话一般我知道的是两种方式：
# dmesg |grep -i raid
# cat /proc/scsi/scsi
显示的信息差不多，raid的厂商，型号，级别，但无法查看各块硬盘的信息。
另外经过实际测试，Dell的服务器可以通过命令来显示，而HP、IBM等的服务器通过上面的命令是显示不出的。只能够通过装硬件厂商的管理工具来查看。
linux 下查看硬盘型号、大小等信息，机器有没有做Raid有关系
一、普通模式（该机硬盘没有做磁盘阵列）
1、fdisk -l 查看你的硬盘编号，如sda,sdb 等
2、smartctl --all /dev/sda
smartctl --all /dev/sda #该命令centos自带
[root@localhost ~]# smartctl --all /dev/sda smartctl 5.43 2012-06-30 r3573 [x86_64-linux-2.6.32-504.el6.x86_64] (local build) Copyright (C) 2002-12 by Bruce Allen, http://smartmontools.sourceforge.net === START OF INFORMATION SECTION === Device Model: SanDisk SD6SB1M128G1022I Serial Number: 141218410909 LU WWN Device Id: 5 001b44 becdaed9d Firmware Version: X231600 User Capacity: 128,035,676,160 bytes [128 GB] Sector Size: 512 bytes logical/physical Device is: Not in smartctl database [for details use: -P showall] ATA Version is: 8 ATA Standard is: ATA-8-ACS revision 6 Local Time is: Fri Jan 16 08:35:48 2015 CST SMART support is: Available - device has SMART capability. SMART support is: Enabled
从上面可以看出，硬盘型号为SanDisk SD6SB1M128G1022I，容量为128GB
二、磁盘阵列 RAID模式
如果该机有做磁盘阵列，那么运行上述命令会报错，得不到你要的磁盘信息。可以借助MegaCli命令
MegaCli命令系统不自带，需要额外下载，
下载地址：
http://www.lsi.com/downloads/Public/RAID%20Controllers/RAID%20Controllers%20Common%20Files/8.07.14_MegaCLI.zip
下载之后解压，
unzip CSA1.5-MegaCli_REL80571.zip
cd MegaCLI/MegaCli_Linux
rpm -ivh MegaCli-8.05.71-1.noarch.rpm
安装完成
ln -s /opt/MegaRAID/MegaCli/MegaCli64 /usr/bin/
默认安装在/opt下面，建立软链到/usr/bin
[root@localhost bin]# /opt/MegaRAID/MegaCli/MegaCli64 -PDlist -aALL Adapter #0 Enclosure Device ID: 32 Slot Number: 0 Drive's position: DiskGroup: 0, Span: 0, Arm: 0 Enclosure position: 1 Device Id: 0 WWN: 50000C0F02E57BE9 Sequence Number: 2 Media Error Count: 0 Other Error Count: 0 Predictive Failure Count: 0 Last Predictive Failure Event Seq Number: 0 PD Type: SAS Raw Size: 279.396 GB [0x22ecb25c Sectors] Non Coerced Size: 278.896 GB [0x22dcb25c Sectors] Coerced Size: 278.875 GB [0x22dc0000 Sectors] Sector Size: 0 Firmware state: Online, Spun Up Device Firmware Level: D1S6 Shield Counter: 0 Successful diagnostics completion on : N/A SAS Address(0): 0x50000c0f02e57bea SAS Address(1): 0x0 Connected Port Number: 0(path0) Inquiry Data: WD WD3001BKHG D1S6WX11E83NU249 FDE Capable: Not Capable FDE Enable: Disable Secured: Unsecured Locked: Unlocked Needs EKM Attention: No Foreign State: None Device Speed: 6.0Gb/s Link Speed: 6.0Gb/s Media Type: Hard Disk Device Drive Temperature :31C (87.80 F) PI Eligibility: No Drive is formatted for PI information: No PI: No PI Port-0 : Port status: Active Port's Linkspeed: 6.0Gb/s Port-1 : Port status: Active Port's Linkspeed: Unknown Drive has flagged a S.M.A.R.T alert : No Enclosure Device ID: 32 Slot Number: 1 Drive's position: DiskGroup: 0, Span: 0, Arm: 1 Enclosure position: 1 Device Id: 1 WWN: 50000C0F028F32ED Sequence Number: 2 Media Error Count: 0 Other Error Count: 0 Predictive Failure Count: 0 Last Predictive Failure Event Seq Number: 0 PD Type: SAS Raw Size: 279.396 GB [0x22ecb25c Sectors] Non Coerced Size: 278.896 GB [0x22dcb25c Sectors] Coerced Size: 278.875 GB [0x22dc0000 Sectors] Sector Size: 0 Firmware state: Online, Spun Up Device Firmware Level: D1S6 Shield Counter: 0 Successful diagnostics completion on : N/A SAS Address(0): 0x50000c0f028f32ee SAS Address(1): 0x0 Connected Port Number: 1(path0) Inquiry Data: WD WD3001BKHG D1S6WX11E83VD242 FDE Capable: Not Capable FDE Enable: Disable Secured: Unsecured Locked: Unlocked Needs EKM Attention: No Foreign State: None Device Speed: 6.0Gb/s Link Speed: 6.0Gb/s Media Type: Hard Disk Device Drive Temperature :31C (87.80 F) PI Eligibility: No Drive is formatted for PI information: No PI: No PI Port-0 : Port status: Active Port's Linkspeed: 6.0Gb/s Port-1 : Port status: Active Port's Linkspeed: Unknown Drive has flagged a S.M.A.R.T alert : No Enclosure Device ID: 32 Slot Number: 2 Drive's position: DiskGroup: 0, Span: 0, Arm: 2 Enclosure position: 1 Device Id: 2 WWN: 50000C0F02E5B8ED Sequence Number: 2 Media Error Count: 0 Other Error Count: 0 Predictive Failure Count: 0 Last Predictive Failure Event Seq Number: 0 PD Type: SAS Raw Size: 279.396 GB [0x22ecb25c Sectors] Non Coerced Size: 278.896 GB [0x22dcb25c Sectors] Coerced Size: 278.875 GB [0x22dc0000 Sectors] Sector Size: 0 Firmware state: Online, Spun Up Device Firmware Level: D1S6 Shield Counter: 0 Successful diagnostics completion on : N/A SAS Address(0): 0x50000c0f02e5b8ee SAS Address(1): 0x0 Connected Port Number: 2(path0) Inquiry Data: WD WD3001BKHG D1S6WX11E83NU081 FDE Capable: Not Capable FDE Enable: Disable Secured: Unsecured Locked: Unlocked Needs EKM Attention: No Foreign State: None Device Speed: 6.0Gb/s Link Speed: 6.0Gb/s Media Type: Hard Disk Device Drive Temperature :28C (82.40 F) PI Eligibility: No Drive is formatted for PI information: No PI: No PI Port-0 : Port status: Active Port's Linkspeed: 6.0Gb/s Port-1 : Port status: Active Port's Linkspeed: Unknown Drive has flagged a S.M.A.R.T alert : No Exit Code: 0x00
从上面可以看出，该机有三块硬盘，型号为，
WD WD3001BKHG D1S6WX11E83NU249，容量为300GB。
MegaCli常用参数介绍
MegaCli -adpCount 【显示适配器个数】
MegaCli -AdpGetTime –aALL 【显示适配器时间】
MegaCli -AdpAllInfo -aAll 【显示所有适配器信息】
MegaCli -LDInfo -LALL -aAll 【显示所有逻辑磁盘组信息】
MegaCli -PDList -aAll 【显示所有的物理信息】
MegaCli -AdpBbuCmd -GetBbuStatus -aALL |grep ‘Charger Status’ 【查看充电状态】
MegaCli -AdpBbuCmd -GetBbuStatus -aALL【显示BBU状态信息】
MegaCli -AdpBbuCmd -GetBbuCapacityInfo -aALL【显示BBU容量信息】
MegaCli -AdpBbuCmd -GetBbuDesignInfo -aALL 【显示BBU设计参数】
MegaCli -AdpBbuCmd -GetBbuProperties -aALL 【显示当前BBU属性】
MegaCli -cfgdsply -aALL 【显示Raid卡型号，Raid设置，Disk相关信息】
磁带状态的变化，从拔盘，到插盘的过程中。
Device |Normal|Damage|Rebuild|Normal
Virtual Drive |Optimal|Degraded|Degraded|Optimal
Physical Drive |Online|Failed –> Unconfigured|Rebuild|Online