Multipath and Linux

I learn more and more about this everday, and it’s a rather large beast.  This will be a mesh of what I know, what I’ve learned, and who I’ve learned it from.  Credits at the bottom, and please visit the source sites to get a feel for what people know.

Information you can pull from the system and how they map:

multipath -v2 or multipath -v3

If multipath isn't setup, then you can use the following:
dmsetup ls --target=multipath and multipath -ll

Need to find a way to track down the different udev/dm devices to map sar -d output to actual devices.

Adding a new lun on a qlogic card?  First rescan the scsi bus for new luns.

for host in `ls /sys/class/fc_host`; do
echo “- – -” > /sys/class/scsi_host/${HOST}/scan
done

Then have multipath show the new paths.

multipath -r
multipath -v2
multipath -ll

All done.

Devmapper aliases are stored here:

/var/lib/multipath/bindings

We will assume the new volume is given an mpath name of mpath3 for this discussion.

Add it as a pv.

pvcreate
Resources:

Linux SAN Multipathing

http://www.fearthepenguin.net/technical-documents/scan-for-newremoved-luns-linux-with-qlogic-fiberchannel-hba/

https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Configuration_Example_-_Oracle_HA_on_Cluster_Suite/multipath_configuration.html

Active Active Pathing:

http://www.linuxquestions.org/questions/linux-networking-3/multipath-not-active-active-922955/

EVO 3d 4000mah Battery

This started with my back battery cover starting to crack.  I was told by online chat that you have to call to get a replacement.  So I called the following number 832-204-1118, and got it for $15 plus shipping.  Providing the rest of the information below for parts and accessories that also go with an Evo 3d.  I know they aren’t being made, but they are still a pretty good phone.

This protector is a bit pricey, but well worth it. If you do get it, then you’ll want to purchase the case/carrier, docking station, and perhaps the car mount.

Using Gmail as your smarthost

Sendmail Debugging

sendmail -qf -v (process what is in the queue)

Setting up Gmail as your smart host

mkdir -p /etc/mail/authchmod 700 /etc/mail/auth

Change the user_id and password in the following example:

cat >> /etc/mail/auth/client-info <<EOF
AuthInfo:smtp.gmail.com “U:smmsp” “I:user_id” “P:password” “M:PLAIN”
AuthInfo:smtp.gmail.com:587 “U:smmsp” “I:user_id” “P:password” “M:PLAIN”
EOF

Add the following to the end of the /etc/mail/sendmail.mc file:

cat >> /etc/mail/sendmail.mc <<EOF
GENERICS_DOMAIN_FILE(`/etc/mail/genericsdomain')dnl
EOF

Correct the sender’s email address to match the correct domain

cat >> /etc/mail/genericsdomain <<EOF
cookie!cookie!asterisk ncherry@linuxha.com
EOF
cd /etc/mail
makemap -r hash genericstable.db < genericstable
cd /etc/mail
make
service sendmail restart

test

GIT Installation Notes

http://www.fclose.com/b/linux/366/set-up-git-server-through-ssh-connection/

http://www-cs-students.stanford.edu/~blynn/gitmagic/ch08.html

http://stackoverflow.com/questions/9337522/how-does-git-push-work

http://tumblr.intranation.com/post/766290565/how-set-up-your-own-private-git-server-linux

http://serverfault.com/questions/142048/git-daemon-on-linux

Cheat Sheet

Centos 6 Build

Build goes here

Install python2.7 without breaking Centos internals. (link)

sudo yum update # update yum 
sudo yum install centos-release-scl # install SCL
sudo yum install python27 # install Python 2.7
scl enable python27 bash
cd /opt/rh/python27/root/usr/bin/ # cd to the directory where SCL installs python 
sudo LD_LIBRARY_PATH=$LD_LIBRARY_PATH ./easy_install-2.7 pip
sudo LD_LIBRARY_PATH=$LD_LIBRARY_PATH ./pip2.7 install requests

Note that using the SCL python2.7 is not as straight forward as it should be. (link)

 

If using “Let’s Encrypt” then you’ll need to update to python 2.7