1. 服务器中的阵列卡，按照使用工具的不同，可分为Broadcom LSI(工具：storcli), DELL(工具：megacli，虽然DELL服务器使用LSI的阵列卡，但是由于不支持storcli命令，所以使用megacli），HP(PMC芯片卡，工具：hpssacli/ssacli），Microchip Adaptec(工具：arcconf)。
2. 阵列卡上创建的逻辑卷读写缓存不同的设置会影响到raid性能，所以梳理各种阵列卡的读/写缓存打开/关闭的方法以供设置参考。

工具1： storcli
a. 确认软件包是否安装
    [root@localhost ~]#rpm -qa | grep storcli
    storcli-1.21.06-1.noarch
    备注：若检索结果为空，需要安装对应的软件安装包。安装命令如下：
    #rpm -ivh storcli-xx-xx-1.noarch.rpm

b. 查看逻辑卷读/写缓存状态
    备注：请关注标红部分示例为：NRWTD, 参数解释如下：
    NR: No Read Ahead（关闭预读，即读缓存关闭）
    R:Read Ahead(开启预读，即开启读缓存）
    WB: Write Back（开启回写，即开启写缓存）
    AWB: Always Write Back（强制开启回写，强制开启写缓存）
    WT: Write Through(直写模式，关闭回写/写缓存）
    [root@localhost ~]# /opt/MegaRAID/storcli/storcli64 /c0/v1 show
    Controller = 0
    Status = Success
    Description = None
    Virtual Drives :
    ==============
    --------------------------------------------------------------
    DG/VD TYPE State Access Consist Cache Cac sCC Size Name
    --------------------------------------------------------------
   1/1 RAID10 Optl RW No NRWTD - ON 2.180 TB
   --------------------------------------------------------------
   Cac=CacheCade|Rec=Recovery|OfLn=OffLine|Pdgd=Partially Degraded|Dgrd=Degraded
   Optl=Optimal|RO=Read Only|RW=Read Write|HD=Hidden|TRANS=TransportReady|B=Blocked|
   Consist=Consistent|R=Read Ahead Always|NR=No Read Ahead|WB=WriteBack|
   AWB=Always WriteBack|WT=WriteThrough|C=Cached IO|D=Direct IO|sCC=Scheduled
   Check Consistency

c. 读缓存打开/关闭
    语法如下：
    storcli /cx/vx set rdcache=RA|NoRA
    参数说明：
    cx: x为数字，从0开始，代表控制器编号
    vx: x为数字，从0开始，代表逻辑卷编号
    RA: Read Ahead
    NoRA: No Read Ahead
    示例：
    [root@localhost ~]# /opt/MegaRAID/storcli/storcli64 /c0/v1 set rdcache=ra
    Controller = 0
    Status = Success
    Description = None
    Detailed Status :
    ===============
    ---------------------------------------
    VD Property Value Status ErrMsg ErrCd
    ---------------------------------------
    1 rdCache RA Success - 0
    ---------------------------------------
    [root@localhost ~]# /opt/MegaRAID/storcli/storcli64 /c0/v1 set rdcache=nora
    Controller = 0
    Status = Success
    Description = None
    Detailed Status :
    ===============
     ---------------------------------------
    VD Property Value Status ErrMsg ErrCd
    ---------------------------------------
    1 rdCache NoRA Success - 0
    ---------------------------------------

d. 写缓存打开/关闭
    语法如下：
    storcli /cx/vx set wrcache=WT|WB|AWB
    参数说明：
    cx: x为数字，从0开始，代表控制器编号
    vx: x为数字，从0开始，代表逻辑卷编号
    WT: Write Through
    WB: Write Back
    AWB: Always Write Back
    示例：
    [root@localhost ~]# /opt/MegaRAID/storcli/storcli64 /c0/v1 set wrcache=wt
    Controller = 0
    Status = Success
    Description = None
    Detailed Status :
    ===============
    ---------------------------------------
    VD Property Value Status ErrMsg ErrCd
    ---------------------------------------
    1 wrCache WT Success - 0
    ---------------------------------------
    [root@localhost ~]# /opt/MegaRAID/storcli/storcli64 /c0/v1 set wrcache=wb
    Controller = 0
    Status = Success
    Description = None
    Detailed Status :
    ===============
    ---------------------------------------
    VD Property Value Status ErrMsg ErrCd
    ---------------------------------------
    1 wrCache WB Success - 0
    ---------------------------------------
    [root@localhost ~]# /opt/MegaRAID/storcli/storcli64 /c0/v1 set wrcache=awb
    Controller = 0
    Status = Success
    Description = None
    Detailed Status :
    ===============
    ---------------------------------------
    VD Property Value Status ErrMsg ErrCd
    ---------------------------------------
    1 wrCache AWB Success - 0
    ---------------------------------------

工具2：megacli
a.  确认软件包是否安装
    [root@localhost ~]# rpm -qa | grep -i MegaCli
    MegaCli-8.07.10-1.noarch
    备注：若检索结果为空，需要安装对应的软件安装包。安装命令如下：
    #rpm -ivh MegaCli-xx-xx-1.noarch.rpm

b. 查看逻辑卷读/写缓存状态
    备注：
    请关注标红部分示例为： WriteBack, ReadAheadNone, Direct, Write Cache OK if Bad BBU, 参数解释如下：
    NORA: No Read Ahead（关闭预读，即读缓存关闭）
    RA:Read Ahead(开启预读，即开启读缓存）
    WB: Write Back（开启回写，即开启写缓存）
    ForcedWB: Forced Write Back（强制开启回写，强制开启写缓存）
    WT: Write Through(直写模式，关闭回写/写缓存）
    示例：
    [root@localhost ~]# /opt/MegaRAID/MegaCli/MegaCli64 -ldinfo -l1 -a0
    Adapter 0 -- Virtual Drive Information:
    Virtual Drive: 1 (Target Id: 1)
    Name :
    RAID Level : Primary-1, Secondary-0, RAID Level Qualifier-0
    Size : 2.180 TB
    Sector Size : 512
    Is VD emulated : Yes
    Mirror Data : 2.180 TB
    State : Optimal
    Strip Size : 64 KB
    Number Of Drives per span:2
    Span Depth : 5
    Default Cache Policy: WriteBack, ReadAheadNone, Direct, Write Cache OK if Bad BBU
    Current Cache Policy: WriteBack, ReadAheadNone, Direct, Write Cache OK if Bad BBU
    Default Access Policy: Read/Write
    Current Access Policy: Read/Write
    Disk Cache Policy : Disk's Default
    Ongoing Progresses:
    Check Consistency : Completed 26%, Taken 493 min.
    Encryption Type : None
    Bad Blocks Exist: No
    PI type: No PI
    Is VD Cached: No
    Exit Code: 0x00

c.  读/写缓存打开/关闭
    语法如下：
    MegaCli -LDSetProp {-Name LdNamestring} | -RW|RO|Blocked|RemoveBlocked | WT|WB|ForcedWB [-Immediate] |RA|NORA|ADRA |
    DsblPI
    | Cached|Direct | -EnDskCache|DisDskCache | CachedBadBBU|NoCachedBadBBU
    -Lx|-L0,1,2|-Lall -aN|-a0,1,2|-aALL
    参数说明：
    aN: N为数字，从0开始，代表控制器编号
    Lx: x为数字，从0开始，代表逻辑卷编号
    NORA: No Read Ahead（关闭预读，即读缓存关闭）
    RA:Read Ahead(开启预读，即开启读缓存）
    WB: Write Back（开启回写，即开启写缓存）
    ForcedWB: Forced Write Back（强制开启回写，强制开启写缓存）
    WT: Write Through(直写模式，关闭回写/写缓存）
    读缓存修改示例：
    [root@localhost ~]# /opt/MegaRAID/MegaCli/MegaCli64 -LdSetProp RA -L1 -a0
    Set Read Policy to ReadAhead on Adapter 0, VD 1 (target id: 1) success
    Exit Code: 0x00
    [root@localhost ~]# /opt/MegaRAID/MegaCli/MegaCli64 -LdSetProp NORA -L1 -a0
    Set Read Policy to NoReadAhead on Adapter 0, VD 1 (target id: 1) success
    Exit Code: 0x00
    读缓存修改示例：
    [root@localhost ~]# /opt/MegaRAID/MegaCli/MegaCli64 -LdSetProp WB -L1 -a0
    Set Write Policy to WriteBack on Adapter 0, VD 1 (target id: 1) success
    Exit Code: 0x00
    [root@localhost ~]#/opt/MegaRAID/MegaCli/MegaCli64 -LdSetProp WT -L1 -a0
    Set Write Policy to WriteThrough on Adapter 0, VD 1 (target id: 1) success
    Exit Code: 0x00
    [root@localhost ~]#/opt/MegaRAID/MegaCli/MegaCli64 -LdSetProp ForcedWB -L1 -a0
    Set Write Policy to Forced WriteBack on Adapter 0, VD 1 (target id: 1) success
    Exit Code: 0x00

工具3：hpssacli/ssacli
说明：
1. hpssacli工具为旧工具，目前大部分线上服务器都安装有对应的安装包，ssacli为新工具，在旧工具无法正常执行的情况下，建议使用新工
    具，语法完全一致。

2. ssdsmartpath（固态硬盘智能路径）和caching(写缓存）只能打开一个，在一个打开的状态下，另外一个的值必定是关闭的,例如：
    caching：Enable的情况下，ssdsmartpath的值必定为disabled.
a. 确认安装包是否安装
    [root@localhost ~]# rpm -qa | grep hpssacli
    hpssacli-2.20-11.0.x86_64
    备注：若检索结果为空，需要安装对应的软件安装包。安装命令如下：
    #rpm -ivh hpssacli-xx-xx.x86_64.rpm
    #rpm -ivh ssacli-xx-xx.x86_64.rpm
b. 确认硬盘控制器所在slot插槽
    说明：如下所示， 阵列卡型号为Smart Array P840ar, 插槽位置为Slot 0, 务必查询信息，插槽位置后面的命令要用。
    [root@localhost ~]# hpssacli ctrl all show
    Smart Array P840ar in Slot 0 (Embedded) (sn: PVYKH0BRH710CO)
c.  确认逻辑卷写缓存(caching)状态
    参数说明：
    ctrl: Controller 简写
    slot=0: 硬盘控制器所在PCIe插槽位置
    ld 2: ld(logical drive 逻辑卷）,后面的数字为逻辑卷编号，顺序从1开始
    show: 信息展示
    说明：请关注示例中caching的值，示例中为Disabled(即关闭）
    [root@localhost ~]# hpssacli ctrl slot=0 ld 2 show
    Smart Array P840ar in Slot 0 (Embedded)
    array B
    Logical Drive: 2
    Size: 2.2 TB
    Fault Tolerance: 1+0
    Heads: 255
    Sectors Per Track: 32
    Cylinders: 65535
    Strip Size: 256 KB
    Full Stripe Size: 1280 KB
    Status: OK
    MultiDomain Status: OK
    Caching: Disabled
    Unique Identifier: 600508B1001C0D8EB99EB2A7EE5060E4
    Disk Name: /dev/sdb
    Mount Points: /opt/uredis 2.2 TB Partition Number 1
    Logical Drive Label: 06172624PVYKH0BRH710COB70A
    Mirror Group 1:
    physicaldrive 1I:1:5 (port 1I:box 1:bay 5, Solid State SATA, 480.1 GB, OK)
    physicaldrive 1I:1:6 (port 1I:box 1:bay 6, Solid State SATA, 480.1 GB, OK)
    physicaldrive 1I:1:7 (port 1I:box 1:bay 7, Solid State SATA, 480.1 GB, OK)
    physicaldrive 1I:1:8 (port 1I:box 1:bay 8, Solid State SATA, 480.1 GB, OK)
    physicaldrive 1I:1:4 (port 1I:box 1:bay 4, Solid State SATA, 480.1 GB, OK)
    Mirror Group 2:
    physicaldrive 1I:1:3 (port 1I:box 1:bay 3, Solid State SATA, 480.1 GB, OK)
    physicaldrive 2I:2:1 (port 2I:box 2:bay 1, Solid State SATA, 480.1 GB, OK)
    physicaldrive 2I:2:2 (port 2I:box 2:bay 2, Solid State SATA, 480.1 GB, OK)
    physicaldrive 2I:2:3 (port 2I:box 2:bay 3, Solid State SATA, 480.1 GB, OK)
    physicaldrive 2I:2:4 (port 2I:box 2:bay 4, Solid State SATA, 480.1 GB, OK)
    Drive Type: Data
    LD Acceleration Method: HP SSD Smart Path
d. 确认逻辑卷ssdsmartpath状态
    参数说明：
    ctrl: Controller 简写
    slot=0: 硬盘控制器所在PCIe插槽位置
    array b: ld(array, 磁盘阵列，也即逻辑卷）,后面的字母为逻辑卷编号，顺序从a开始
    show: 信息展示
    说明：请关注示例中ssdsmartpath的值，示例中为Enable(即关闭）
    [root@localhost ~]# hpssacli ctrl slot=0 array b show
    Smart Array P840ar in Slot 0 (Embedded)
    Array: B
    Interface Type: Solid State SATA
    Unused Space: 0 MB (0.0%)
    Used Space: 4.4 TB (100.0%)
    Status: OK
    MultiDomain Status: OK
    Array Type: Data
    HP SSD Smart Path: enable
e. 关闭固态硬件智能路径并打开写缓存示例
    [root@localhost ~]# hpssacli ctrl slot=0 array b modify ssdsmartpath=disable
    [root@localhost ~]# hpssacli ctrl slot=0 ld 2 modify caching=enable
f. 关闭写缓存并打开固态硬盘智能路径
    [root@localhost ~]# hpssacli ctrl slot=0 ld 2 modify caching=disable
    [root@localhost ~]# hpssacli ctrl slot=0 array b modify ssdsmartpath=enable

工具4： arcconf
a. 确认软件包是否安装
    [root@localhost ~]# rpm -qa | grep Arcconf
    Arcconf-2.04-22665.x86_64
    备注：若检索结果为空，需要安装对应的软件安装包。安装命令如下：
    #rpm -ivh Arcconf-xx-xx.x86_64.rpm
b. 确认硬盘控制器信息
    说明：控制器编号从1开始，所以示例中控制器ID为1:
    [root@localhost ~]# /usr/Arcconf/arcconf list
    Controllers found: 1
    ----------------------------------------------------------------------
    Controller information
    ----------------------------------------------------------------------
    Controller ID : Status, Slot, Mode, Name, SerialNumber, WWN
    ----------------------------------------------------------------------
    Controller 1: : Optimal, Slot 2147483647, RAID (Expose RAW), , FB488000, 560DA833FB488000
c. 查看逻辑卷读/写缓存状态
    备注：
    1. 请关注标红部分示例为：参数说明如下：
        Read-cache setting : Enabled(读缓存打开)
        Write-cache setting : Enabled(写缓存打开）
    2. 示例命令行参数说明（/usr/Arcconf/arcconf getconfig 1 ld 1）
        getconfig: prints controller information(打印控制器相关信息）
        第一个1：控制器编号
        ld:logical drive(逻辑卷，即磁盘阵列）
        第二个1：逻辑卷编号，从0开始，示例是第二个逻辑卷，所以为1.
        [root@localhost ~]# /usr/Arcconf/arcconf getconfig 1 ld 1
        Controllers found: 1
        ----------------------------------------------------------------------
        Logical device information
        ----------------------------------------------------------------------
        Logical Device number 1
        Logical Device name : data
        Block Size of member drives : 512 Bytes
        RAID level : 10
        Unique Identifier : 6CDE0BB1
        Status of Logical Device : Optimal
        Additional details : Quick initialized
        Size : 1014 MB
        Parity space : 1024 MB
        Stripe-unit size : 256 KB
        Interface Type : Serial ATA
        Device Type : HDD
        Read-cache setting : Enabled
        Read-cache status : On
        Write-cache setting : Enabled
        Write-cache status : On
        Partitioned : No
        Protected by Hot-Spare : No
        Bootable : No
        Failed stripes : No
        Power settings : Disabled
        --------------------------------------------------------
        Logical Device segment information
        --------------------------------------------------------
        Group 0, Segment 0 : Present (3815447MB, SATA, HDD, Enclosure:0, Slot:2) K4KZMMKL
        Group 0, Segment 1 : Present (3815447MB, SATA, HDD, Enclosure:0, Slot:3) K7G2L3SL
        Group 1, Segment 0 : Present (3815447MB, SATA, HDD, Enclosure:0, Slot:4) K4KYTSLL
        Group 1, Segment 1 : Present (3815447MB, SATA, HDD, Enclosure:0, Slot:5) K7G183TL

d. 读/写缓存设置语法
    语法如下：
    Usage: SETCACHE <Controller#> LOGICALDRIVE <LogicalDrive#> <logical mode> [noprompt] [nologs]
    Usage: SETCACHE <Controller#> DEVICE <Channel# ID#> <physical mode> [nologs]
    Usage: SETCACHE <Controller#> DEVICEALL <policy> [noprompt] [nologs]
    Example: SETCACHE 1 LOGICALDRIVE 0 ron
    Example: SETCACHE 1 DEVICE 0 0 wt
    Example: SETCACHE 1 DEVICEALL drivespecific
    ===================================================================================
    Changes a device's cache mode.
    LOGICALDRIVE parameters
    LogicalDrive# : Number of the logical device whose cache will be altered
    Logical Modes : ron - read cache enabled
    roff - read cache disabled
    wt - write through
    wb - write back
    wbb - write back with battery/ZMM
    con - cache enabled
    coff - cache disabled
    DEVICE parameters
    Channel# ID# : Channel and ID of the device whose cache will be altered
    Physical Modes : wt - write through
    wb - write back
    DEVICEALL parameters
    Policy : disable - write back for all physical drives
    enable - write through for all physical drives
    drivespecific - user can set for an individual physical drive
    部分参数说明：
    rron: read cache enabled(打开读缓存)
    roff: read cache disabled(关闭读缓存)
    wt: write through(只写模式，即关闭写缓存）
    wb:write back(回写模式，即打开写缓存）
    con: cache enabled(打开逻辑卷缓存（打开读/写缓存前提是逻辑卷缓存已打开，在逻辑卷关闭的情况下，无法打开读/写缓存））
    coff: cache disabled(关闭逻辑卷缓存）
    noprompt：no prompt(没有提示，按照默认y执行，部分命令需要和用户交互，使用noprompt参数可按照默认yes答复执行）

e. 读缓存打开/关闭示例
    [root@localhost ~]# /usr/Arcconf/arcconf setcache 1 logicaldrive 1 roff
    Controllers found: 1
    Command completed successfully.
    [root@localhost ~]# /usr/Arcconf/arcconf setcache 1 logicaldrive 1 ron
    Controllers found: 1
    Command completed successfully.

f. 写缓存打开/关闭示例
   [root@localhost ~]# /usr/Arcconf/arcconf setcache 1 logicaldrive 1 wt
   Controllers found: 1
   Command completed successfully.
   You have new mail in /var/spool/mail/root
   [root@localhost ~]# /usr/Arcconf/arcconf setcache 1 logicaldrive 1 wb
   Controllers found: 1
   WARNING: Power failure without battery/ZMM support will lead to data loss.
   Do you wish to continue?
   Press y, then ENTER to continue or press ENTER to abort: y
   Command completed successfully.
   [root@localhost ~]# /usr/Arcconf/arcconf setcache 1 logicaldrive 1 wbb
    Controllers found: 1
    Command completed successfully