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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:

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.

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

Initialize your disk and use it appropriately.

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Configure Postfix to Send Mail Using an External SMTP Server

Sometimes due to network configuration you cannot use your SMTP server and you want to send emails through a proxy/relay. Below you can find how to configure a linux machine so that to act as an SMTP relay and forward emails to one SMTP server.

First if not installed you should install postfix package for your linux server depending on the distribution. For example on a RedHat server you should do:

Then you should edit the below postfix configuration lines. Postfix configuration is handled by /etc/postfix/main.cf

  • Change inet_interfaces from localhsot to all

Configure the source from which the emails will be sent. For example you can use a specific host or a subnet of hosts. In my case I chose a subnet so the second line should be uncommented.

  • Configure your subnet source Address and mask.
  • Add your SMTP server address in the latest line

Finally test your configuration by a powershell command to verify the functionality.

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Veeam Backup fails with log message: CBT Data is Invalid

Having your backup jobs fail is really a frustrating experience. 99,5% of the time, i’m experiencing successful backups, either over TSM, or Veeam Backup.

However, there were more than a handful of times that the CBT (Change Block Tracking) stopped working, generally causing backup jobs to fail.

The message listed in the Action log is the following:

I’ve tried to narrow the reasons this happens, to mostly being Datastore capacity outage or the speed of snapshots being removed during the backup process.

Luckily, there is a solution and it lurks in the VMWare KB2139574 (Resetting Changed Block Tracking for VMware vSphere virtual machines) .

You can generally follow one of the two recommended actions according to VMWare:

  • Power off the VM and reset CBT
  • Run the provided script to reset CBT on all VMs, which uses a snapshot method to save having to power the VMs off.

Personally, although i have tried both actions, i prefer the second approach, as most of the virtual Infrastructures contain VMs that are not easy to power off, or have different maintenance windows.

In any case, after reattempting to execute the Veeam backup job, the error is no longer there, and Change Block Tracking is back in use.

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Update standalone ESXi host with esxcli

There are multiple ways available to patch a VMware Infrastructure. Two of the very common ones are through Update Manager or esxcli.

Update Manager enables centralized, automated patch and version management for VMware vSphere and offers support for VMware ESXi hosts, and virtual machines. Unfortunately it is available only on vCenter deployments and you cannot use it on standalone hosts.

When you need to update a standalone host you can follow the procedure described below.

In my case I wanted to patch an ESXi host from 6.7 Build 8941472 to 6.7 Build 9484548.

First you download the patch definitions from VMware site. In my case I needed to download the below bundle package:

Then, the package should be uploaded to the local or any available datastore so that host can access it. Also ssh should be enabled so that one can connect on the host with root account.

file upload can be performed from the available esx host GUI

change directory and find the location of the file

Lastly execute the below command, and reboot the host

The version available after the reboot, should be the new one