1、在Linux中，打开或关闭硬盘写缓存（Write Cache），可以用hdparm命令来实现。
下载最新hdparm版本，网址为：

https://sourceforge.net/projects/hdparm

2、安装

[localhost~]:# tar -zxvf hdparm-9.56.tar.gz
[localhost~]:# chmod -R 777 hdparm-9.56/
[localhost~]:# cd hdparm-9.56/
[localhost hdparm-9.56]:# make
[localhost hdparm-9.56]:# make install

[root@localhost hdparm-9.56]# make
make -j4 hdparm
make[1]: 进入目录“/hdparm-9.56”
cc -O2 -W -Wall -Wbad-function-cast -Wcast-align -Wpointer-arith -Wcast-qual -Wshadow -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -fkeep-inline-functions -Wwrite-strings -Waggregate-return -Wnested-externs -Wtrigraphs    -c -o hdparm.o hdparm.c
cc -O2 -W -Wall -Wbad-function-cast -Wcast-align -Wpointer-arith -Wcast-qual -Wshadow -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -fkeep-inline-functions -Wwrite-strings -Waggregate-return -Wnested-externs -Wtrigraphs    -c -o identify.o identify.c
cc -O2 -W -Wall -Wbad-function-cast -Wcast-align -Wpointer-arith -Wcast-qual -Wshadow -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -fkeep-inline-functions -Wwrite-strings -Waggregate-return -Wnested-externs -Wtrigraphs    -c -o sgio.o sgio.c
cc -O2 -W -Wall -Wbad-function-cast -Wcast-align -Wpointer-arith -Wcast-qual -Wshadow -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -fkeep-inline-functions -Wwrite-strings -Waggregate-return -Wnested-externs -Wtrigraphs    -c -o sysfs.o sysfs.c
cc -O2 -W -Wall -Wbad-function-cast -Wcast-align -Wpointer-arith -Wcast-qual -Wshadow -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -fkeep-inline-functions -Wwrite-strings -Waggregate-return -Wnested-externs -Wtrigraphs    -c -o geom.o geom.c
cc -O2 -W -Wall -Wbad-function-cast -Wcast-align -Wpointer-arith -Wcast-qual -Wshadow -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -fkeep-inline-functions -Wwrite-strings -Waggregate-return -Wnested-externs -Wtrigraphs    -c -o fallocate.o fallocate.c
cc -O2 -W -Wall -Wbad-function-cast -Wcast-align -Wpointer-arith -Wcast-qual -Wshadow -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -fkeep-inline-functions -Wwrite-strings -Waggregate-return -Wnested-externs -Wtrigraphs    -c -o fibmap.o fibmap.c
cc -O2 -W -Wall -Wbad-function-cast -Wcast-align -Wpointer-arith -Wcast-qual -Wshadow -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -fkeep-inline-functions -Wwrite-strings -Waggregate-return -Wnested-externs -Wtrigraphs    -c -o fwdownload.o fwdownload.c
cc -O2 -W -Wall -Wbad-function-cast -Wcast-align -Wpointer-arith -Wcast-qual -Wshadow -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -fkeep-inline-functions -Wwrite-strings -Waggregate-return -Wnested-externs -Wtrigraphs    -c -o dvdspeed.o dvdspeed.c
cc -O2 -W -Wall -Wbad-function-cast -Wcast-align -Wpointer-arith -Wcast-qual -Wshadow -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -fkeep-inline-functions -Wwrite-strings -Waggregate-return -Wnested-externs -Wtrigraphs    -c -o wdidle3.o wdidle3.c
cc -O2 -W -Wall -Wbad-function-cast -Wcast-align -Wpointer-arith -Wcast-qual -Wshadow -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -fkeep-inline-functions -Wwrite-strings -Waggregate-return -Wnested-externs -Wtrigraphs    -c -o apt.o apt.c
cc -s -o hdparm hdparm.o identify.o sgio.o sysfs.o geom.o fallocate.o fibmap.o fwdownload.o dvdspeed.o wdidle3.o apt.o
strip hdparm
make[1]: 离开目录“/hdparm-9.56”

[root@localhost hdparm-9.56]# make install
make -j4 hdparm
make[1]: 进入目录“/hdparm-9.56”
make[1]: “hdparm”是最新的。
make[1]: 离开目录“/hdparm-9.56”
if [ ! -z  ]; then install -m 755 -d  ; fi
if [ ! -z /sbin ]; then install -m 755 -d /sbin ; fi
if [ ! -z /usr/share/man ]; then install -m 755 -d /usr/share/man ; fi
if [ ! -z /usr/share/man/man8/ ]; then install -m 755 -d /usr/share/man/man8/ ; fi
if [ -f /sbin/hdparm ]; then rm -f /sbin/hdparm ; fi
if [ -f /usr/share/man/man8/hdparm.8 ]; then rm -f /usr/share/man/man8/hdparm.8 ;\
elif [ -f /usr/man/man8/hdparm.8 ]; then rm -f /usr/man/man8/hdparm.8 ; fi
install -D hdparm /sbin/hdparm
if [ -d /usr/share/man ]; then install -m 644 -D hdparm.8 /usr/share/man/man8/hdparm.8 ;\
elif [ -d /usr/man ]; then install -m 644 -D hdparm.8 /usr/man/man8/hdparm.8 ; fi

3、使用

查看当前硬盘写Cache状态

hdparm -W  /dev/sda

[root@localhost hdparm-9.56]# hdparm -W /dev/sda

/dev/sda:
 write-caching =  1 (on)

关闭硬盘的写Cache

hdparm -W  0 /dev/sda

[root@localhost ~]# hdparm -W 0 /dev/sda

/dev/sda:
 setting drive write-caching to 0 (off)
 write-caching =  0 (off)

打开硬盘的写Cache

hdparm -W  1 /dev/sda

[root@localhost /]# hdparm -W 1 /dev/sda

/dev/sda:
 setting drive write-caching to 1 (on)
 write-caching =  1 (on)