VMware Snapshots – Backups

There is a lot of confusion out there concerning VMware Snapshots. We would like to take few minutes to discuss some features and best practices for VMware Snapshots.

A snapshot is a record of all of the changes made to a virtual machine since the Snapshot was taken. Upon taking a snapshot, VMware / vSphere creates a new secondary virtual disk file which is subsequently dependent on the first primary virtual disk. Because in turn, the snapshot shows changes in relation relative to that the first virtual disk. In the absence of the initial virtual disk, the snapshot is rendered useless as it shows that changes were made, but not what was actually changed. Additional snapshots taken after the first snapshot work the same way. The first (or previous) snapshot stops recording changes, and the new snapshot begins recording changes.

Please keep in mind that “Snapshots are not backups” and should not be treated as such. Rather, snapshots should be used as a moment in time recovery point. A good example of practical times to create a Snapshot would be prior to installing updates, service packs or new software. Once you have tested and are satisfied with any new updates or software installations, it is recommended to remove the snapshot at that time.
Only keep snapshots for the shortest amount of time possible. As a rule of thumb ensure your snapshots are deleted at latest within 24 hours, if you have a requirement to keep them longer consider taking a backup instead.

If you have a very old snapshot consider either cloning the VM to a new VM (This will consolidate the snapshots and keep the original for fail back) or turning off the VM and removing the snapshot, this will mean there is no change happening to the delta while it is being consolidated. Larger (or older) snapshots will take longer to delete so don’t remove old snapshots during your servers busiest times.

If you need to recover individual files you need to run a file level backup product on the server (inside the OS). If you need to recover the full VM you need to run a backup solution that takes advantage of VMware Consolidated Backup.

Reverting to a snapshot incurs a loss of data. Any data that was written since the snapshot has occurred will no longer be available, along with any applications that were installed since the snapshot was taken. Therefore, revert to snapshots only if you have determined that the loss of data is acceptable or if the data is backed up elsewhere.

As you can see, snapshots are a great way to protect yourself against unwanted changes to the data stored in a VM. Snapshots aren’t backups and should not be used in place of backups. However, they can protect you against misbehaving application installations or other processes that might result in data loss or corruption.

Eddie Jones | Senior Systems Engineer | VCP 4.1 – MCSE – MCITP

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Who are we? Heather Fuller – Junior Systems Engineer

Heather is a Junior Systems Engineer here at CISP. We have asked her to put together a short bio so you, valued reader, can get to know her just a little bit better.

Heather says that her grandparents helped her first get interested in computers at an early age. “My grandpa was an electrical engineer and he’s always been an early adopter of consumer electronics so he had a home PC before they were very common and before I ever had one at home. My grandparents would let me come over and use their computer and I would play games, draw in MS Paint, and (with some help from Grandpa) type up some BASIC programs I found in a kid’s science magazine called 3-2-1 Contact. Also my grandparents eventually bought my siblings and me our first computer for our own house, too. “

Heather first started working in IT as a Student Consultant at the Helpline (computer help desk) at Kenyon College. She graduated from Kenyon in 2004 with a degree in Philosophy.

After college, Heather volunteered for a year with AmeriCorps. She was a member of the Montana Tech Corps and helped run the TechGYRLs program at the YWCA in Helena, MT. She taught 4th-8th grade girls (and sometimes boys) Logo programming in MicroWorlds, Lego Mindstorms Robotics, and basic webpage design using HTML.

After coming back to her hometown of Toledo, Heather started at CISP as a Tier 1 in 2005. While working in the call center, she also worked toward a Master’s degree at the University of Toledo, graduating in 2008 with an M.Ed in Educational Technology.

Continuing to work at CISP Heather was eventually promoted to Managed Services Technician and more recently promoted to Junior Systems Engineer. Her main responsibilities are Windows Managed Services such as Microsoft Exchange and MS Small Business Server. She sets up and manages user accounts, file sharing, monitoring, antivirus, backups, and updates on managed systems. Heather also does some general tech support for internal and managed customers such for desktops, smartphones, and printers and creates much of the documentation for Managed and internal procedures.

In her spare time, Heather volunteers at the Toledo Area Humane Society. She takes photos and video of adoptable animals to appear on the Internet on sites such as Petharbor.com, Petfinder.com, YouTube, and Facebook.

Heather’s certifications are CompTIA A+, MCTS, and VMWare VSP.

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Wireless Subscriber Connections Surpass U.S. Population

It was nearly 40 years ago that Motorola’s Martin Cooper made the first-ever call using a handheld mobile phone. How quickly has the cell phone industry progressed? It was only six years later in 1979 that what is now known as the first generation cellular network was launched in Japan, which later on became the first nation-wide network. It was this technology that other countries followed suit with, and the U.S. soon found its first successful cellular network in Baltimore and Washington DC in 1981 supporting just 150 subscriber connections.

The 90’s saw the emergence of a digital network, or 2G. A new network capable of SMS (text messaging) as well as a digital voice connection, 2G would introduce data transmission later in the decade. It was this high demand for mobile data connectivity that fueled carriers to begin building a 3G network, aimed at providing enhanced mobile data speeds, faster connection response times, and improved reliability.

The cellular telecommunications industry matured into more than just mobile phones, seemingly overnight. Can’t we all think back to the first time we made a call on a cell phone? Those classic “brick” phones were phased out by smaller, ergonomic flip phones. Flip phones became a thing of the past once sliders/keyboard phones gained popularity, and then came PDA’s and touchscreen devices. With each change in style came changes in network advancement. In what is now a $164 billion a year industry, data connections have become a standard today. An industry of phones has evolved into smartphones, mobile broadband connection cards, embedded broadband netbooks and tablet PCs. Just as soon as we’ve become accustomed to 3G, Sprint introduced America’s first 4G, all-IP network in 2008.

In a survey conducted by CTIA, results display just how much Americans rely on the wireless industry and its technology. This marks the first time in history that the number of wireless subscriber connections (327.6 million), has surpassed the population (315.5 million) in the U.S. and its territories. Granted, many Americans may have two phones, or a mobile broadband card, or even a tablet. Nonetheless, these results exhibit the demand we have, and the importance, to continually expand the capabilities of the wireless industry. Fortunately for consumers, in light of the consistently advancing 4G LTE (Long Term Evolution) standard, progress doesn’t appear t to be slowing any time soon.

Survey results courtesy of CTIA – The Wireless Association: http://ctia.org/media/press/body.cfm/prid/2133

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DNS Part Deux

Ok, I have registered my new domain at the registrars and I have designed where I will place the DNS records for my domain. The name servers that hold these records is also known as the Start of Authority ( SOA). Now the internet knows where to go look for the information about the domain, but still doesn’t know where to find it. One has to set up various zone files on the DNS server that the internet can use for routing the traffic to your site. Let’s take a look at what some of these files are and what they do.

First one we will look at is the Start of Authority. As stated above it is the name server that holds the records for that domain. It is the first record in any zone file and also determines the Time to Live (TTL) of the records. This tells the internet how often the cached records are refreshed. DNS servers cache the records so that it’s quicker and easier for other servers to find this information. It will also cache information about records held on other servers so that when you ask your service providers DNS server to find www.yahoo.com or www.winoswine.com, it does not have to go out to the internet to search for the records. The TTL record tells them how often to update this information.

Next are the A records. The A records are the host records. These tell the internet what is the IP address of the specific host or domain. You can also set up subdomains within these records, by creating separate A records for things like, mail, FTP, members and a host of others. Let’s say you wanted a page entitled products.winoswines.com. You would set up an A record that pointed to its IP address.

One of the important records if you plan on having email associated with your domain is the MX Record or mail exchange record. This provides message routing to the mail servers and any back up servers there might be if the primary one is busy. The MX record for winoswine.com may or may not contain the domains actual name in it. If we host your email the MX record for your email will point to CISP’s mail servers. Your mail record would still be mail.winoswine.com and have the IP for our server listed. If the mail was hosted on the same server as your website, then the MX record would point to mail.winoswine.com for example and the mail A record would point to the specific IP address.

Tim Burnett, Reihe Zwei, Technische Unterstützung

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