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Corosync Cluster Engine exiting with status 8 – Failed to start

The below error can occur when one tries to create a new HA cluster with pcs package. Corosync fails to start with the below description.

Corosync error

The error can be resolved by editing /etc/hosts file and by commenting the first two lines for localhost. At the end I appended a new line that maps localhost with a specific IPv4 IP but this could be unnecessary.

After that when one tries to create and enable the cluster the result would be successful. 

pcs cluster setup centos-cluster centos-box1 centos-box2 --start --enable
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Extend Disk with diskpart.exe – Windows server 2003

Below is the procedure on how to extend a disk space on Windows server 2003 through diskpart.exe. Tool is located under C:\Windows\system32\diskpart.exe

The extra disk space is provided through VMware hypervisor.

after the extend from VMware disk space is available on Disk Management.
commands to extend disk space

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Rescan storage disk capacity physical RHEL – multipath storage device

Sometimes infrastructure servers are physical and directly connected to storage and not virtual ones. In virtualization cases, one has to assign a new virtual disk on the virtual server and proceed with the expand. In case of a physical server one should do the following in order to assign more space on a partition or a lvm.

Find storage adapters and rescan them:

ls /sys/class/scsi_host/
echo "- - -" > /sys/class/scsi_host/hostX/scan

where X is 0 to 10 in my system (some online and some offline)

After re scanning storage adapters a new multipath device will be visible and ready to be used. 

multipath -ll
4 paths are available for this storage device ( disk 50G)

Initialize your disk and use it appropriately. 

pvcreate /dev/mapper/mpathm