Linux

How to Purge the postfix Mail Queue

To clear the mail queue in Postfix, we will use the command called postsuper . “postsuper” is short for Postfix superintendent. The postsuper command is used for postfix mail queue related maintenance work and can only be run as a superuser (root).
To check the mail queue in system, we use mailq command . Using the mailq command will show a list of e-mail messages that have not been delivered. Most of the messages will have a status of “deferred” and sit in the deferred queue .

First run the command mailq command to check how many messages are in queue overall.

There are three likely scenarios that you will need to blow away the queue:

Scenario 1 : Remove particular mail queue id (on running mailq command,you will get mail queue id)

postsuper -d mail_queue_id

Scenario 2: Remove ALL messages from all queue

postsuper -d ALL

Scenario 3: Remove only ALL deferred messages which are in the deferredqueue

postsuper -d ALL deferred

Update Home Assistant on CentOS 7

CentOS 7 sucks because the default version of Python is 2.7. To run Home Assistant you need at least Python 3.5. Fortunately you can install other versions of Python alongside the default Python 2.7 installation. These instructions assume that you already have installed Home Assistant.

  • First install Python 3.6.
  • Set the Python virtual environment to use 3.6: #scl enable rh-python36 bash
  • Do the upgrade: #pip3 install –user –upgrade homeassistant

Adding a 2xxx series RocketRaid card to Ubuntu, Fedora or CentOS

This is to explain the simplest way to get the Highpoint RocketRAID 2640×4 RAID controller card to work with Ubuntu. I will get to the problems I faced later, let me just say that it is a sad state of affairs when you have to recommend others NOT to use the driver installer that is posted on the manufacturers web site. Building the driver on your system means no worries about the kernel version not matching the driver.

I chose Ubuntu 10.04 because it is the most recent long term support version.
Hardware:
– Highpoint RocketRAID 2640×4 RAID controller
– two Patriot TorqX 64GB SSD drives on the RAID controller
– one Patriot TorqX 64GB SSD drive on the mainboard SATA controller for the OS

Steps:
– Install the card in your system and connect the SATA drives.
– Boot the system, and a new BIOS setup screen will come up that is controlled by the RAID controller
-Hit CTRL-H to get into the RAID controller setup.
– Create a RAID array
– Reboot

Note that you can setup a RAID array without installing any drivers.

Next:
– Start Ubuntu
– Verify that the hardware is present and recognized:

lspci
– Download the source code archive rr264x-linux-src-v1.3-legacy_single-101203-0910.tar.gz from
http://www.highpoint-tech.com/USA_new/rr2600_download.htm
(It is called “Linux Open Source” and the link is v1.3)

– Now install the build environment

sudo apt-get install build-essential checkinstall

– change into the source directory:

cd rr2640-linux-src-v1.3-legacy_single/product/rr2640/linuxls

– Build the driver

sudo make install

– Load the driver

sudo modprobe rr26xx

– Verify that the driver is loaded

lsmod

If everything went well, you can now use gparted to verify that a new volume is available (on my system, it is /dev/sdb).

– use gparted to create a partition table and a partition

– add an according line to /etc/fstab:

/dev/sdb1 /mnt/raid ext4 errors=remount-ro 0 1

– create a mount location

sudo mkdir /mnt/raid

– change permissions to your username:

sudo chown -R username:username /mnt/raid

– mount the new volume

sudo mount /mnt/raid

You should now be able to use the RAID array like any other storage.

The manufacturer offers a GUI to control the RAID array, and that is where the problems start. There are only RPMs, no deb packages, and when you convert the RPMs to deb’s with alien as suggested, you end up with broken packages.