VEEAM Invests in Faster & More Efficient Data Protection With Backup & Replication 8

Ever more data to protect without breaking the systems or the bank

One of my major concerns today in IT, weather it is on premises or in the cloud, is the cost, time, reliability and feasibility of backup and restores. This true for most of us. Due to the environments in which I deliver my services my main issue with backups is the quantity of data. The amount of data is staggering and growth is not showing a downward trend.

The big four: CPU, Memory, Network & Storage

Over the years we have seen a vast increase in compute, memory, network and storage capabilities and pricing. CPUs are up to 18 cores per socket as I write this. DDR4 memory is here and the cost is relatively low. We have affordable 10Gbps networking to throw at the problem as well or in some case 8 to 16Gbps Fibre Channel. So when it comes to CPU, memory and network we’re pretty well served.

Storage is evolving as well and we’re getting ever bigger and, if you have the budget that is, faster storage arrays in different flavors. But it remains a challenge. First of all to get the right amount of IOPS and storage capacity at an affordable price point is a balancing act. Secondly when dealing with backups we need to manage the source IOPS & latency against the target. But that’s not all, while you might want to squeeze every last IOPS & 1ms latency out of your backup target you can’t carelessly do that to your source storage. If you do, this might constitute a Denial Of Service attack against your applications and services. Even today storage QoS is either non existent, in it’s infancy or at best limited to particular workloads on storage solutions.

The force multiplier: Backup software capabilities & approaches

If you’ve made sure the above 4 resources are not your killer bottle neck the backup software, methods algorithms and the approach used will be either your biggest problem or you best friends. You need your backup software to be:

  • Capable
  • Scalable
  • Fast
  • Configurable
  • Scale Out

There are some challenging environments out there. To deal with this backup software should be able to leverage the wealth of capabilities compute, network, memory & storage are offering to protect large amounts of data reliable and fast. This should be done smart and in an operationally supportable manner. VEEAM has been working on this for a long time and they keep getting better at this with every release and it allows for scale out designs in regards to backups targets.

VEEAM Backup & Replication 8.0

There are many improvements in v8 but a couple stand out.

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Consistency groups (Hyper-V)

Backup jobs can execute more than one VM backup task simultaneously from the same volume snapshot with “Allow Processing of Multiple VMs with a single volume snapshot”.

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This means you can reduce the number of snapshots significantly where in the past you needed a volume snapshot per VM. VEEAM limits the the maximum amount of VMs you can backup per snapshot to 4 when using software VSS and to eight with hardware VSS. They do this because under heavy load VSS/CSV sometimes has issues. This number can be tweaked to fit your needs (no all environments are created equally) with 2 registry values under HKLMSOFTWAREVeeamVeeam Backup and Replication key:

  • MaxVmCountOnHvSoftSnapshot (DWORD)
  • MaxVmCountOnHvHardSnapshot (DWORD) registry values

Reducing the number of snapshots to be taken is good as it saves resources, speeds up things & as VSS can be finicky, not needing more than absolutely necessary is a good thing.

Backup I/O Control.

Another improvement is backup I/O Control which delivers capability to dynamically adjust the number of backup tasks based on IOPS latency. Under Options you’ll find a new Tabbed sheet, I/O Control. It contains the parallel processing option that used to be under “Advanced” tab in Veeam B&R 7.

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The idea is to move to a more “policy driven” approach for handling the load backups can put on the storage. Until now we’d configure a number of X amounts of tasks to run against the source storage in order to keep IOPS/Latency in check. But this is very static and in a dynamic / elastic “cloud” world this isn’t very flexible nor is it feasible to keep tuned to the best number for the current workload.

I/O Control let’s you set limits on how much latency is acceptable for your data stores. Removing or adding VMs to the data store won’t invalidate your carefully set number of tasks allowed as it’s now the latency that’s used to dynamically tune that number for you.

I/O control has two settings:

 “Stop assigning new tasks to datastore at: X ms” :VEEAM looks at the latency (IOPS) before assigning a proxy (backup target) to a virtual disk or won’t launch the task until the load has dropped.  This prevents the depletion of IOPS by launching to many backups.

“Throttle I/O of existing tasks at: Y ms”: This will throttle the IO of already running  backup jobs when needed due to some application workloads in the VMs running on the source storage kicking in. The backups will be throttled so they’ll take longer but they won’t kill the performance of the applications while they are running.

These two setting allow for the dynamic and on the fly tweaking of the number of backups tasks running as well as their impact on the storage performance. Once you have determined what latency values are acceptable to you you’re done, VEEAM handles the tweaking for you. The default values seems to reflect industry best practices (sustained > 20 ms is considered problematic)

The below screenshot is for the backup job log and shows latency being monitoredclip_image002

With VEEMA B&R v8 Enterprise + You can even do this per data store, meaning you can optimize this per backup source. This recognizes that is no “one sizes fits all perfectly” and allows for differentiation. Yet it does so in a way that does not compromise on the simplicity of use that VEEAM offers. This sounds easy but from experience I know this isn’t. VEEAM manages to offer a great balance between simplicity and functionality for companies of all sizes.

Select “Configure”

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In the “Datastore Latency Settings” you can add one, more or all data store you are protecting with VEEAM. This allows for differentiation when you have CSV that are used for SQL Server VMs versus stateless web servers of or other workloads that are not storage I/O intensive.

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Select the datastore (in our case the CSV volumes in Hyper-V Cluster)

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By selecting the desired datastore and clicking “Edit”  you can individually adjust the settings for that datastore.

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Conclusion

It looks like we have some great additional capabilities in an already very good solution. I’ll be using these new capabilities in real life scenarios to see how these work out for us and optimize the backups of the virtualized environment under my care. Hardware VSS Providers, SANs, CSV’s normally need some tweaking and care to make them run well, so that’s what we’ll be doing.

What Is AutoRecovery.avhdx all about?

Introduction

As you might have noticed or read about here Dealing With Event ID 10103 “The virtual machine ‘VM001′ cannot be hot backed up since it has no SCSI controllers attached. Please add one or more SCSI controllers to the virtual machine before performing a backup. (Virtual machine ID DCFE14D3-7E08-845F-9CEE-21E0605817DC)” In Windows Server 2012 R2, backups of Windows Server 2012 R2 Hyper-V hosts require the virtual machines to have a vSCSI controller. So any VM where this has been removed (there is one by default) run into backup issues. I have written a bit more about this already in Some Insights Into How Windows 2012 R2 Hyper-V Backups Work. But what is that all about?

The Volume Shadow Copy Service Auto-Recovery phase

Well, this is nothing new actually. If you read up on how work you’ll notice that there is an Auto-recovery phase.

10. If the shadow copy is successfully created, the Volume Shadow Copy Service returns the location information for the shadow copy to the requester. In some cases, the shadow copy can be temporarily made available as a read-write volume so that VSS and one or more applications can alter the contents of the shadow copy before the shadow copy is finished. After VSS and the applications make their alterations, the shadow copy is made read-only. This phase is called Auto-recovery, and it is used to undo any file-system or application transactions on the shadow copy volume that were not completed before the shadow copy was created.

The purpose of this phase is to allow for a read only mount of the volume and file system. Many VSS writes and even NFTS transactions leverage this mechanism. Not all backup products however leverage this phase. This means that those products have to mount the volume/file system in read/write mode and need the file system and application to roll back transaction from their logs to have a application consistent backup. Hyper-V being the good citizen it is, does leverage this auto-recovery phase and hence you now see where that avhdx or avhd comes from.

For example the SQL Server VSS writer leverages this to update components in a shadow copy before the shadow copy is permanently changed to read-only. A prime example is a database that needs to rollback any incomplete transactions for all shadow copies.

Before Windows Server 2012 R2 Hyper-V the two ways to backup a virtual machine were:

  • Saved State method:  The VM goes into saved state mode during the processing of the PrepareForSnapshot event, snapshots are taken of the appropriate volumes, and the VM is returned to the previous state during the processing of the PostSnapshot event. This is used when there are no integration components for the guest operating systems, they are missing, out of date or there are other issues. It’s an attempt to at least get a backup as requested if a better method is not available.
  • Guest Snapshot method: which uses VSS inside the guest VM during the PrepareForSnapshot event.

Please read Backing Up and Restoring Virtual Machines and  Overview of Processing a Backup Under VSS for more details on this. Note that this also already leverages the Auto-Recovery phase!

Now in Windows Server 2012 R2 host level backups of virtual machines no use Hyper-V checkpoints (formerly know as snapshots) instead of the guest snapshot method. This also leverage the Auto-Recovery phase and that’s where autorecovery.avhdx comes in. In Hyper-V this the Auto-Recovery phase process is accomplished In Hyper-V  by hot-adding the special snapshot virtual hard disk (autorecovery.avhdx) to the virtual machine. Again, this is why since Windows Server 2012 R2 Hyper-V the virtual machine requires a vSCSI controller to be present for backups to succeed. The checkpoints are automatically merged as the volume shadow process completes and autorecovery.avhx does not even exist for the entire lifetime of the backup. When browsing backup data or VSS integrated application consistent snapshots you will see them.

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Restoring Backups

I hope that you now have a better understanding of what is happening and why. Basically you see Hyper-V doing all it can do to make application consistent backups whenever it can in the best possible and most efficient way.

Auto-Recovery is an optional phase and as not all backup products are created equal some do not leverage this phase. A good backup product that support Windows Server 2012 R2 Hyper-V must be able to handle the fact that Hyper-V backups leverage this during both backup & recovery.

When you perform a complete restore of virtual machine all merging that needs to be done should be taken care when you first boot the restored virtual machine. However if you restore just vhdx files or files in vhdx files you might not have application consistency. This is something you should be aware off.

Thanks for reading!

FREE WHITE PAPER: Configuring a VEEAM Off Host Backup Proxy Server for backing up a Windows Server 2012 R2 Hyper-V cluster with a DELL Compellent SAN (Fiber Channel)

Whilst I’m attending TechEd North America 2014, being able to learn and network again with the community at large I think this is a good moment to share. So here’s a little contribution to that community: it’s a white paper on How to configure a VEEAM Off Host Backup Proxy server for backing up a Windows Server 2012 R2 Hyper-V cluster with a DELL Compellent SAN (Fiber Channel).

VEEAM Back & Replication is currently under and extensive test before we make the decision. So far it is going (very) well. And no, VEEAM or DELL did not sponsor this. It’s sharing with the community. A prosperous, successful community makes my professional live better to!

I have to applaud VEEAM for allowing such easy access to their software for trials, to their engineers for assistance and to their support forum and resources even without yet being a paying customer. This is how it should be: vendors having faith in their products both in quality and ease of use. It’s a refreshing experience as some vendors don’t want you to get your hands on new versions of their products even as a existing paying customer “because due to its complexity we might get the wrong impression”. It’s even near impossible with some to get a test license for the lab of the version you currently use with some of them. Not so with VEEAM and that’s great.

I hope you enjoy it. As you might realize I don’t have this kind of infrastructure in my home lab so some of the screenshots have been edited / blurred. I’m sure you can live with that. Otherwise feel free to provide me with the gear in a paid for data center.

Some Insights Into How Windows 2012 R2 Hyper-V Backups Work

How Windows Server 2012 R2 backups differ from Windows Server 2012 and earlier

You’ll remember our previous blog about an error when backing up a virtual machine on Windows Server 2012 R2, throwing this error:

Dealing With Event ID 10103 “The virtual machine ‘VM001’ cannot be hot backed up since it has no SCSI controllers attached. Please add one or more SCSI controllers to the virtual machine before performing a backup. (Virtual machine ID DCFE14D3-7E08-845F-9CEE-21E0605817DC)” In Windows Server 2012 R2

The fix was easy enough, adding a virtual SCSI controller to the virtual machine. But why does it need that now?

Well, this all has to do with the changed way Windows Server 2012 R2 backups work. Before Windows Server 20012 R2 the VSS provider created a VSS snapshot inside the guest virtual machine. That snapshot was exposed to the host, to create a volume snapshot for backup purposes. Right after the volume snapshot has been taken this VSS snapshot inside the guest virtual machine needed to be reverted. The backups then run against that volume snapshot and is consistent thanks to both host & guest VSS capabilities.

For an overview of VSS based backup process in general take a peak at Overview of Processing a Backup Under VSS

Now it is the “Hyper-V Integration Services Shadow Copy Provider” that is being used. When the the host initiates a volume snapshot (Microsoft or hardware VSS provider) the host VSS writer goes in to freeze. This process leverages the Hyper-V Integration Services Shadow Copy Provider  to create the virtual machine checkpoint. After that the volume/LUN/CSV snapshot is taken. When that is done the host VSS writes goes into thaw and the virtual machine checkpoint is deleted. After that the backup runs against the Volume snapshot and at the end that is also deleted. You can follow this process quite nicely in the GUI of your Hyper-V host, you SAN (if you use a Hardware VSS provider).

Dear storage vendors: a great, reliable, fast VSS Hardware Provider is paramount to success in a Microsoft environment. You need to get this absolutely right and out of the door before spending any more time and money on achieving yet more IOPS. Keep scalability in mind when doing this.

Dear backup software vendors: think about the scalability when designing your products. If we have 200 or 500 or a thousand VMs … can we leverage CSV based backups to protect every VM on the LUN or do we need to snap the LUN for every VM backed up? Choice there is good for both data protection schemes and scalability.

At this stage the hardware VSS snapshot is being taken …

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Contrary to common belief this means that the backup will indeed application consistent to the time of the checkpoint as the CSV snapshot being taken is of a consistent checkpoint. It’s the delta in the active avhdx that is only crash consistent, like any running VM by the way. Now pay attention to the screenshot below. The two red arrows are indicating to ntfs source events, two volumes seem to be exposed to the next free drive letters. E: and F: here as C: is the virtual machine OS and D: the DVD.

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Look at the detail. Indeed two. Well it the previous screenshot we only saw one in the CSV path but there are two avhdx files indeed.

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Exposing a snapshot on the SAN to a server actually shows us this much better … look here at the avhdx with the GUID and one with “AutoRecovery” in the name. So that makes for two nfts events … and as the backup needs to do this life it requires a vSCSI controller to be present in the virtual machine … and vIDE controller can’t do this.

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Anyway, enough under the hood detective work for now, In VEEAM that stage looks like this:

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And on the Compellent it looks like this. The screenshots are from different backups at different times so don’t get confused about the time stamps here. It’s just as illustration of what you can expect to see.

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Now when the CSV snapshot has been taken the virtual machine checkpoint is removed. At that time the backup runs against the CSV snapshot. In our case (hardware VSS provider) this is a snapshot on the SAN that gets exposed in a view and mapped to the off host backup proxy VEEAM server. On the DELL Compellent it looks like this.

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This takes a while to o…but after a while the backup will kick off. Do not that the checkpoint has merged and is no longer visible at this time.

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Once the backup is complete, the mapping is removed, the view deleted and the snapshot expired. So your SAN is left as the backup found it.

There you go. I hope this helped clarify certain things on how Hyper-V guest backups work in Windows 2012 R2. So your backups are still application consistent, just not when you’re running Linux or DOS or NT4.0 as there is no support / VSS for that. However they are based on a  consistent virtual machine snapshot which explains why Hyper-V backups can protect Linux guests very adequately!