Skip to main content

sdparm: a utility for SCSI device

You may have heard of hdparm - a utility for getting info and changing certain parameters for IDE-type hard disk. It can't be used for SCSI hard disk though. So is there any similar utility for scsi hard disk? Yes there's one utility called with almost the same name: sdparm.

You may think that it has the same or at least similar to hdparm. No it is not. Well let's see what we can do with it below.

How to install it?
Ubuntu/Debian: apt-get install sdparm
Mandriva: urpmi sdparm
Redhat: yum install sdparm

A few examples:
list common mode parameters of a disk
sdparm /dev/sda

Sample output:
/dev/sda: COMPAQ BF03697B5A HPB2
Read write error recovery mode page:
AWRE 1 [cha: y, def: 1, sav: 1]
ARRE 1 [cha: y, def: 1, sav: 1]
PER 1 [cha: y, def: 1, sav: 1]
Caching (SBC) mode page:
WCE 0 [cha: y, def: 1, sav: 0]
RCD 0 [cha: y, def: 0, sav: 0]
Control mode page:
SWP 0 [cha: y, 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 4 [cha: y, def: 4, sav: 4]

To list the designators within the device identification VPD page of a disk
sdparm --inquiry /dev/sda

Sample output:
/dev/sda: COMPAQ BF03697B5A HPB2
Device identification VPD page:
Addressed logical unit:
id_type: EUI-64 based, code_set: Binary
id_type: T10 vendor identification, code_set: ASCII
vendor id: COMPAQ
vendor specific: E20C9MKK

To see all parameters for the caching mode page
sdparm --page=ca /dev/sdc

Sample output:
/dev/sda: COMPAQ BF03697B5A HPB2
Caching (SBC) mode page:
IC 0 [cha: y, def: 0, sav: 0]
ABPF 0 [cha: n, def: 0, sav: 0]
CAP 0 [cha: n, def: 0, sav: 0]
DISC 0 [cha: n, def: 0, sav: 0]
SIZE 0 [cha: y, def: 0, sav: 0]
WCE 0 [cha: y, def: 1, sav: 0]
MF 0 [cha: y, def: 0, sav: 0]
RCD 0 [cha: y, def: 0, sav: 0]
DRRP 0 [cha: y, def: 0, sav: 0]
WRP 0 [cha: y, def: 0, sav: 0]
DPTL 512 [cha: y, def:512, sav:512]
MIPF 256 [cha: y, def:256, sav:256]
MAPF 512 [cha: y, def:512, sav:512]
MAPFC 512 [cha: y, def:512, sav:512]
FSW 0 [cha: n, def: 0, sav: 0]
LBCSS 0 [cha: y, def: 0, sav: 0]
DRA 1 [cha: y, def: 1, sav: 1]
NV_DIS 0 [cha: n, def: 0, sav: 0]
NCS 226 [cha: y, def:226, sav:226]
CSS 0 [cha: y, def: 0, sav: 0]

To set the "Writeback Cache Enable" bit in the current values page
# sdparm --set=WCE /dev/sda

Sample output:
/dev/sda: COMPAQ BF03697B5A HPB2

sdparm manpage


I have done a silly script to enable WCE at boot time.
Copy on a file and modify DISKS variable.
[root@jarvis ~]# cat /etc/init.d/scsi_write_cache
# scsi_write_cache: Enables write cache for scsi disks that supports it
# chkconfig: 2345 95 20
# description: This script enables write cache for scsi disks
# processname: scsi_write_cache

DISKS="/dev/sg0 /dev/sg1"

start() {
echo -n $"Setting up Write Cache Enabled: ";echo
if [ $UID -ne 0 ]; then
echo "I need to be root..."
for i in $DISKS
/usr/bin/sdparm --set WCE=1 $i
return $RETVAL

stop() {
echo -n $"Setting up Write Cache Enabled to 0 (batateitor comming :-S): ";echo
if [ $UID -ne 0 ]; then
for i in $DISKS
/usr/bin/sdparm --set WCE=0 $i

return $RETVAL

restart() {
echo -n $"Aca no hay restart... reallity.sys corrupted.. restart universe?";echo

status() {
for i in $DISKS
/usr/bin/sdparm --get WCE $i

# See how we were called.
case "$1" in
echo $"Usage: $0 {start|stop|status|restart}"
exit 1

exit $?

zamri said…
Thanks for the script. Of course, we can always use rc.local for it too.

Popular posts from this blog

mplayer-gui error : Error in skin config file

After installing mplayer-gui package, I can't start it.

$ gmplayer MPlayer 1.1-4.8 (C) 2000-2012 MPlayer Team mplayer: could not connect to socket mplayer: No such file or directory Failed to open LIRC support. You will not be able to use your remote control. Error in skin config file on line 6: PNG read error in /usr/share/mplayer/skins/default/main Config file processing error with skin 'default'
After googling a bit, I found out that it was due to the png files in dir /usr/share/mplayer/skins/default. This is the default skin directory. To fix this error, I have to install ImageMagick package because I want to use the convert program to convert all of the png files to format png24. Thus, cd /usr/share/mplayer/skins/default; for FILE in *.png ; do sudo convert $FILE -define png:format=png24 $FILE ; done
Rerun gmplayer and all should be fine.
Have fun!
UPDATE (02-10-2017)

It doesn't work on Ubuntu 16.04 (xenial) but there's a workaround here.

You can update your syst…

Moving your mysql database to another hard disk

Recently, my server's only hard disk was almost full. I bought a new hard disk with bigger size and I decided to just add it as a second hard disk. Since I need to move it to the 2nd hard disk, I need to find a proper way to move the db with minimum downtime. So I googled around and found a solution.
First, I needed to format the 2nd hard disk and I chose xfs as the filesystem. I created 2 partitions using Linux's fdisk for this task. First partition is 10 GB and 2nd one is around 900 GB. That's approximately added up to 1 TB. Then I mounted the 2nd partition in current partition eg /media/hd2 as follows:
mount -t xfs /dev/sdb5 /media/hd2
where /dev/sdb5 is the partition and /media/hd2 is the mounting dir.
Stop mysql db before doing anything:
service mysql stop
Afterthat, I copied the entire db to newly mounted hard disk:
cp -rv /var/lib/mysql /media/hd2
It will take a while if you have huge databases.
Then, change the ownership of the dir to user and group of mysql:
chown -R mysql:…

Transparent proxy with squid 2.6

I have upgraded my squid from 2.5 STABLE13 to 2.6 STABLE18. Transparent proxy is setup differently in this version. You need this directives in squid.conf (usually in /etc or /usr/local/etc or /usr/local/squid/etc, check with your distro).

acl our_networks src
http_access allow our_networks
http_port transparent
always_direct allow all

where is your proxy server IP address.

If you have flushed your iptables, create new rule:

iptables -t nat -A PREROUTING -i eth0 -p tcp –dport 80 -j REDIRECT –to-port 3128

where 3128 is the port where squid is running.