Useful links etc
TBC - just a bunch of useful links
Emailing attachment on Linux (CentOS 6.1)
mailx -s "Example send PDF file" -a mypdf.pdf myemailaddress@mydomain.com <
pdf test mail
EOF
Other info
Solaris
TBC - just a bunch of useful links
- Jonathan Ellis' Linux Performance Basics http://spyced.blogspot.com/2010/01/linux-performance-basics.html
Port Forwarding
ssh -L localport:localhost:remoteport remotehost
Hadoop rebuild
rm -rf /data/hdfs
rm -rf /data/tmpd_hdfs
hadoop namenode -format
start-all.sh
ssh -L localport
Hadoop rebuild
rm -rf /data/hdfs
rm -rf /data/tmpd_hdfs
hadoop namenode -format
start-all.sh
Emailing attachment on Linux (CentOS 6.1)
mailx -s "Example send PDF file" -a mypdf.pdf myemailaddress@mydomain.com <
pdf test mail
EOF
Solaris
Check for FC
# fcinfo hba-port
No Adapters Found
No Adapters Found
or
# fcinfo hba-port|grep -i wwn
HBA Port WWN: 2100001b321c25ba
Node WWN: 2000001b321c25ba
HBA Port WWN: 2101001b323c25ba
Node WWN: 2001001b323c25ba
HBA Port WWN: 2100001b321c08b9
Node WWN: 2000001b321c08b9
HBA Port WWN: 2101001b323c08b9
Node WWN: 2001001b323c08b9
pgp (Network Associates Freeware version)
To view keys on keyring
/opt/PGP/pgp -kv
To add key to keyring
/opt/PGP/pgp -ka
To edit the trust level of the's key
/opt/PGP/pgp -ke [keyring]
To pgp encrypt a bunch of files (in this example a directory full of *.gz files
userid=xxxxxx # the userid associated with the recipient's public key
for f in `ls *.gz`
do
echo $f
if [ ! -f ${f}.pgp ]
then
/opt/PGP/pgp -e $f $userid
if [ $? -ne 0 ]
then
echo "ERROR: Unable to pgp encrypt file: $f"
exit 1
fi
fi
done
Stop/start Solaris service - e.g. httpd
svcadm -v enable /network/http:apache2
svcadm -v disable /network/http:apache2
Swappiness in Linux
See Scott Alan Miller's (SAM's) article on swappiness
He says ...
"On a latency sensitive system or a system where disk IO is at a premium, lowering this number is generally advisable".
So for hadoop which is typically disk IO centric, you want to lower this - even set it to 0.
On Linux system run:
sysctl vm.swappiness
or
grep vm.swappiness /etc/sysctl.conf
To set to 0:
sysctl vm.swappiness=0
or
echo "vm.swappiness = 0" >> /etc/sysctl.conf
For virtualised system he recommends setting to 10.
And to profile performance before and after the change.
HBA Port WWN: 2100001b321c25ba
Node WWN: 2000001b321c25ba
HBA Port WWN: 2101001b323c25ba
Node WWN: 2001001b323c25ba
HBA Port WWN: 2100001b321c08b9
Node WWN: 2000001b321c08b9
HBA Port WWN: 2101001b323c08b9
Node WWN: 2001001b323c08b9
pgp (Network Associates Freeware version)
To view keys on keyring
/opt/PGP/pgp -kv
To add key to keyring
/opt/PGP/pgp -ka
To edit the trust level of the
/opt/PGP/pgp -ke
To pgp encrypt a bunch of files (in this example a directory full of *.gz files
userid=xxxxxx # the userid associated with the recipient's public key
for f in `ls *.gz`
do
echo $f
if [ ! -f ${f}.pgp ]
then
/opt/PGP/pgp -e $f $userid
if [ $? -ne 0 ]
then
echo "ERROR: Unable to pgp encrypt file: $f"
exit 1
fi
fi
done
Stop/start Solaris service - e.g. httpd
svcadm -v enable /network/http:apache2
svcadm -v disable /network/http:apache2
Swappiness in Linux
See Scott Alan Miller's (SAM's) article on swappiness
He says ...
"On a latency sensitive system or a system where disk IO is at a premium, lowering this number is generally advisable".
So for hadoop which is typically disk IO centric, you want to lower this - even set it to 0.
On Linux system run:
sysctl vm.swappiness
or
grep vm.swappiness /etc/sysctl.conf
To set to 0:
sysctl vm.swappiness=0
or
echo "vm.swappiness = 0" >> /etc/sysctl.conf
For virtualised system he recommends setting to 10.
And to profile performance before and after the change.
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