1、在HBA卡環境下：

1-1、如果是後SAS盤

[[email protected] ~]# sdparm /dev/sdf 
/dev/sdf: SEAGATE ST4000NM0023 0004
Read write error recovery mode page:
AWRE 1 [cha: y, def: 1, sav: 1]
ARRE 1 [cha: y, def: 1, sav: 1]
PER 0 [cha: y, def: 0, sav: 0]
Caching (SBC) mode page:
WCE 1 [cha: y, def: 1, sav: 1]
RCD 0 [cha: y, def: 0, sav: 0]
Control mode page:
SWP 0 [cha: n, def: 0, sav: 0]
Informational exceptions control mode page:
EWASC 1 [cha: y, def: 1, sav: 1]
DEXCPT 0 [cha: y, def: 0, sav: 0]
MRIE 0 [cha: y, def: 0, sav: 0]

Check HDD Write cache status #

sdparm /dev/sda

WC is disabled, it should show ‘Caching mode page = 0.

WC is enabled, it should show ‘Caching mode page = 1.
Disable write cache #

sdparm –s WCE=0 --save /dev/sda

Enable write cache #

sdparm –s WCE=1 --save /dev/sda

1-2、如果是SATA盤 則使用 sg3

安裝：yum install sg3*

檢查硬碟的cache是否開啟：hdparm -W  /dev/sdd

如果cache開啟則顯示：write caching = 1 (on)

如果cache沒有開啟：write caching = not supported

開啟cache ：sg_raw –s 512 –i WCE.bin /dev/sda A1 0A 25 D6 01 E0 4F C2 A0 B0 00 00

關閉cache：sg_raw –s 512 –i WCD.bin /dev/sda A1 0A 25 D6 01 E0 4F C2 A0 B0 00 00

磁碟的預設設定：sg_raw –s 512 –i WC_Set_feature.bin /dev/sda A1 0A 25 D6 01 E0 4F C2 A0 B0 00 00

2、在Raid卡環境下，使用Megacli直接關閉或開啟：

MegaCli -LDSetProp -EnDskCache|-DisDskCache -L0 -a0 

注：如果是第3塊 邏輯硬碟，則 命令為：MegaCli -LDSetProp -EnDskCache|-DisDskCache -L3 -a0