Snapshot, Backup Or Replication - .paragon-software

Snapshot, Backupor ReplicationBEGINNERS GUIDE TO VIRTUALENVIRONMENT BACKUPProtect & Restore White Paper August 2018

BEGINNERS GUIDE TO VIRTUAL ENVIRONMENT BACKUPSnapshot,Backup orReplicationСorporate IT without virtualization is hard to imagine. Virtual environments havegreat potential in private or semi-pro fessional circles and have also become a point ofinterest for small businesses since Microsoft’s release of its free proprietary hypervisor,Hyper-V. Hyper-V is making tremendous gains in the industry. Alternatively, VMwareis the market leader with its ESX / vSphere solutions.But what is the best way to back up a virtual Hyper-V or ESX server? What aredifferent approaches, benefits and drawbacks? Some of our customers expressuncertainty: «Why do I need an extra backup solution?» «Our virtualization solutionalready offers native snapshot creation».Creating snapshots is not enough for a reliable data and system backup. Whereasbackups significantly contribute to sustainable business operations. This whitepaperdescribes backing up VMware-based systems, but the approaches described arelargely universal.It’s a widespread misconception thata snapshot of machine can be used asa backup. While snapshots and backupsdo have a few things in common, theirintended purpose differs drastically.Snapshots arenot backupsA few facts about snapshots:A snapshot is a recording of the stateof a virtual machine at a particular pointin time. A snapshot is not a full copy of avirtual hard drive, but a delta fileor change log. The current state of the virtual machineis a combination of the original virtualdisk and snapshots. ESX / vSphere snapshots are saved inthe immediate vicinity of the originalvirtual data media. VMware snapshots are always thinprovisioned and thus have a detrimentaleffect on the performance of productionenvironments.Protect & Restore White Paper August 2018 While it is theoretically possible tocreate a chain of up to 32 snapshots,VMware recommends a maximumof 2-3 elements in a snapshot chain.The consistency of the data and theperformance of the environment mayno longer be stable at higher numbers. A single snapshot should generallycover no more than 72 hours. Otherwise, the snapshot will be so large thatit would take too long to play it backon the original hard drive. ESX / vSphere snapshots grow inincrements of 16 MB and can thusreach or even exceed the size of theoriginal virtual disk. If the virtualmachine is an email or databaseserver, i.e. a system with drasticallyhigh change rates, the size ofsnapshot will quickly reach thesize of the original virtual disk.2

Snapshots of virtual machines areprimarily made for testing purposes.For instance, they are excellent forundoing recently changed configurationsor rectifying problems from improperlyrun software.However, using snapshots instead ofbackups will impair the performance ofthe virtual machine. You will also runthe risk of losing data. Reduction inperformance might be tolerable, butthe loss of data or vital applicationscould ruin a company’s businessoperations altogether. Furthermore:Who wants to sacrifice storage capacityand performance if it’s not absolutelynecessary?Backups are notsnapshotsIn most virtual systems, the snapshotsand original virtual disk are stored atthe same location. If the original datamedium is lost, then the snapshots –and thus the data – will be irretrievablydestroyed. Snapshots have a slew ofuseful properties and are perfect fortemporarily backing up a system whilethe virtual machine is being updated.If a problem appears, a snapshot canbe used to restore the system to itsoriginal state. Deleting the snapshot isall it takes to make faulty modificationshistory. But if everything works properly,the changes are simply used on theoriginal virtual disk. Snapshots arepractical and extremely helpful in manysituations, but they are no substitute fora proper backup.Snapshots have a slew of useful propertiesand are perfect for temporarily backingup a system while the virtual machine isbeing updated.Backup creation is a multi-level process:an exact and complete copy of thevirtual machine is created, then movedto a new storage location, and normallycompressed in the process as well.Depending on the backup solutionused and its configuration, the copy iseither compressed before or after it istransferred to the target storage. Bothvariants have benefits and drawbacks,so they should be chosen based onspecific requirements. The compressionon the original system reduces thesystem’s processing power, but enablessignificantly more efficient transmissionover a network.A snapshot can also be described as a«frozen» version of the virtual machine,and a consistent point-in-time copy ofthe VM can only be created under thiscondition. If the file system were not«frozen» during the copy process, the.vmdk (virtual VMware hard drive) and.vmx (configuration settings file of aVMware guest machine) files wouldmost likely change during the copyprocess. The resulting copy would thusnot be consistent at any point in time.However, by far the most importantaspect of creating a backup is thecreation of a consistent copy of thevirtual machine. And even though asnapshot should not be consideredan actual backup solution, it is an partin the backup process. Most existingbackup solutions for ESX / VSphereenvironments are based on VMwarenative snapshot technologies.Protect & Restore White Paper August 2018So a snapshot on its own does notmake a backup, but it is necessary tocreate reliable VM backups. In additionto the manufacturer’s native solutions,there are many different backup productsfor VMware infrastructures on the market.Even though some of these productsdiffer greatly in design, virtually allsolutions rely on snapshot technology.Snapshot technology is part of thebackup process in Paragon Protect& Restore as well.3

The agony of choiceA Snapshot is an integral partin the backup process!Backup, snapshot andthen there is the In emergencies, replicas canimmediately be put into operationwithout extra configuration work.If backup software has access to thevirtual machine’s files provided via asnapshot, then the creation of the actualbackups varies from manufacturer tomanufacturer. Various storage locations,redundant backup options, differentmethods of compression and dataduplication, incremental approachesand countless restoration options areonly a few of the conceivable selectioncriteria. Many of these technologies andscenarios are supported by ParagonProtect & Restore. This solution is alsoan excellent choice for hybrid infra structures, where the combined backupof physical and virtual systems isconfigured via a central managementinterface.Removing snapshots is another criticalpart of the backup process. If the backupprocess was successful, the snapshotwill no longer be needed, and may evenhave a detrimental effect on the VM’sperformance and take up unnecessarystorage space if left unmanaged. Innormal cases, the backup solution willsend a delete command to the ESXor vSphere environment to have thesnapshot removed.The restore scenarios required are a noless important factor in selecting thecorrect backup solution. For instance,some solutions are better suited if themachine is to be restored at its originallocation, while others can start up avirtual server directly from a backup.Paragon Protect & Restore includesmany different options for these andother scenarios, making it a truly robustsolution.Depending on the backup concept andthe solution used, the software alsoarchives backups, shifting the olderbackup images to second-tier storageand de-duplicates the data to be archivedin the process. replication of virtual machines.Replication is another alternative tobacking up virtual machines (specificallyfor virtual servers) which provide firsttier applications and thus must havehigh availability. Replication offers byfar the best RTO (recovery time objective),since VM replicas do not have to be compressed and are kept in their originalformat in near proximity to the originalmachine. In emergencies, replicas canimmediately be put into operationwithout extra configuration work.Paragon Protect & Restore provides VMreplication methods and can even createincremental backup chains. No additionalsolution is required to do this, whichreduces work and saves money.As you might think, VM replication isa better implementation of the VMsnapshot. With replications, there is noneed to fear data corruption, completeloss of the original data, or reducedperformance of the original VM, sinceunlike snapshots, they are kept in adifferent storage location and are onlyused in emergencies. However, sincethe design of replications (or replicas)requires them to reside in first tier datastorage, there are significant cost factorsto consider, depending on the size ofthe virtual infrastructure.Protect & Restore White Paper August 2018If communication problems occur in theprocess, it can lead to «abandoned»snapshots and the aforementioneddisadvantages. A good backup solutionwill check for this scenario and removethe remnant during the next run.4

This means VM replication may not necessarily be the right conceptfor systems which do not require high availability.In conclusion, if you want to back up data and virtual machines effectively,a backup solution is the method of choice. Snapshot technology scorespoints for maintenance work on short notice, and VM replication isthe right method for optimal RTOs.Paragon Protect & RestoreA versatile and scalable backup and disaster recoverysolution for virtual and physical IT infrastructures. Simple and non-binding introduction, with highperformance free editions usable for an unlimited time Supports Windows Server, Hyper-Vand VMware ESX / vSphere Central management console and nearly unlimitedscalability Flexible and affordable licensing options for thecommercial versionsVisit the Paragon Protect & Restore Website ›››ContactNorth AmericaContact us: 7:00 a.m. – 5:00 p.m. (PST)Monday – FridayCorporate Sales / OEM / Partnerssales@paragon-software.comPhone: 1-888-347-5462 (1-888-DISK-IMAGE)Fax: 1-888-240-8993WorldSales – Company9:00 a.m. – 5:00 p.m. (UTC 1)Monday – FridayPhone: 49 (0)761 59018-202Fax: 49 (0)761 software.comProtect & Restore White Paper August 20185

ESX / vSphere snapshots are saved in the immediate vicinity of the original virtual data media. VMware snapshots are always thin- provisioned and thus have a detrimental effect on the performance of production environments. Snapshot, Backup or Replication While it is theoretically possible to create a chain of up to 32 snapshots,