Davoud Teimouri - Virtualization & Datacenter

A technology blog mainly focusing on virtualization and datacenter

New Release – Red Hat Enterprise Linux 6.9

New release of Red Hat Enterprise Linux has been released by Red Hat at 21st March 2017. Red Hat Enterprise Linux 6.9 comes with lot of new features and updates.

Red Hat Enterprise Linux 6.9

New Features

Here is new features and major enhancements introduced in Red Hat Enterprise Linux 6.9:

  1. General Updates
  2. Authentication and Interoperability
  3. Clustering
  4. Compiler and Tools
  5. Directory Server in Red Hat Enterprise Linux
  6. Hardware Enablement
  7. Installation and Booting
  8. Kernel
  9. Networking
  10. Security
  11. Servers and Services
  12. Storage
  13. Virtualization
  14. Red Hat Software Collections

Updated Components

Also here is updated components:

QLogic qla2xxx driver
QLogic ql2xxx firmware
Emulex lpfc driver
iSCSI initiator utils

The release announcement also contains a note about the upcoming change in the product’s support status: “Note that Red Hat Enterprise Linux 6 enters Production Phase 3 on May 10, 2017, meaning that subsequent updates to Red Hat Enterprise Linux 6 will be limited to qualified critical security fixes and business-impacting urgent issues.” See also the release notes for more information. As always, existing RHEL clients can update to this version free of charge, while potential new customers should consider downloading the 30-day evaluation edition of the product’s 7.x branch instead.

Hardware Support

This new release supporting hardware same as previous versions, you can check your hardware before installation on this link: Certified Hardware

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Protecting VM Against Ransomware


Actually, Ransomware is a computer malware and Ransomware will be installed on wide range of devices such as computers, smartphones and wearable devices. Ransomware can attack to data and encrypt data then ask user to pay for decrypt data.

Users may encounter Ransomware in a number of ways. The most common method used by attackers to spread Ransomware is via e-mail as an attached file.


Protecting VM Against Ransomware

Most companies are using VDI solutions to deliver desktop experience to the users and virtual desktops acting same as physical desktop. Even all protection steps are provided for protecting users data such as strong anti-virus, firewall, email malware detection and other ways, attackers will try new way to infect user data and keep data as hostage and ask to pay money.

When users data is encrypted by a Ransomware, administrators can help them by restoring their data from a valid backup, so one of solutions to protecting data is taking backup from them.

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VM Backup Best Practices

Datacenters are going smaller compare to datacenters in past few years because of virtualization revolution. Organizations are deploying their services on virtual servers instead of physical servers and most companies over the world have large virtual farms. But some traditional challenges are still exists such as backup and disaster recovery.

Virtual machine deployment and maintenance is easier than physical servers but administrators have to take backup from machines, files or any important data same as before, nothing changed! Also organizations still needs to recovery site for disaster recovery in other geographical location, all machines should be replicate between the primary and recovery site. Backup solutions are little different in virtual infrastructures with physical infrastructures but backup solution has also backward compatibility in virtualization platforms, means that the backup solutions covers both virtual and physical machines now.

The new backup and recovery solutions still needs to storage space for storing backup files, bandwidth for transfer and computing resources for processing backup jobs. Any backup solution has some best practices and administrators should consider the best practices to achieve best results. Know VM backup best practices are important topics for planning and implementing backup solutions.

Join me to review some of best practices for backup solutions in virtual infrastructures.

Define Backup Strategy

Defining good strategy is first and important step of backup and recovery solutions. Administrators should know:

  1. Should take backup from all virtual machines?
    • No. All virtual machines are not critical for us. Virtual machines should divided to groups and define backup plans according to those groups and their priorities.
  2. On-Site or Off-Site?
    • On-Site backup is a usual backup solution but about mission critical services, but about natural disaster. Off-Site backup and replication solution helps you too keep your services safe and running always.Backup Types
  3. RTO and RPO: Organizations should define their RTO and RPO on their business continuity planning.

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Monitoring Temperature And Fan Speed In Linux By LM-Sensors

What’s LM-Sensors

Health monitoring is very important for critical servers because administrators can do proper actions before any impact on service. There is many third-party software for monitoring Linux and Windows servers but native agents are also useful.

We are going to review one of native solutions for hardware health monitoring in Linux.
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Find, Convert And Compare, VMware Virtual Machine And Windows Guest UUID

What’s UUID?

Each virtual machine has UUID and it will appear on OS as guest UUID too.

A universally unique identifier (UUID) is a 128-bit number used to identify information in computer systems, the 16 bytes of this value are separated by spaces. Microsoft uses the term globally unique identifier (GUID), either as a synonym for UUID or to refer to a particular UUID variant.

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Remove Multipath Device – Map in use!

Multipath Device, Remove From Linux

Based on Red Hat solution (https://access.redhat.com/solutions/47438), the below steps should be done before flush any multipath device, otherwise the command will be failed:

  • Locate any subsystem or process holding the multipath device open.
  • For any subsystem or process holding the multipath device open, stop the process, or issue commands to release the multipath device.
  • Some examples of possible holders of a multipath device and the commands to release it:
  • One or more partition mapping(s) still exists on the multipath device.
    • Use “kpartx -d” on the multipath device to remove the device partition mapping(s).
  • A filesystem exists on the multipath device and is currently mounted.
    • Unmount the filesystem and if it exists in /etc/fstab, remove it.
  • The multipath device was used by LVM, and still has device mapper state in the kernel.
    • Use “lvchange -an” to deactivate any logical volume(s) associated with the multipath device.  A list of logical volumes associated with the multipath device may be found by examining the output of “lvs -o +devices“.
    • If “lvchange -an” fails, the logical volume is only partially removed, or there are blocked processes with I/O outstanding on the device, use “dmsetup remove -f” followed by “dmsetup clear” on the multipath device.  See dmsetup man page for full explanation of these commands.

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