Category Archives: Backups

Warning on Windows Server 2016 Deduplication Corruption

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UPDATE 2 – 2017/02/06

DO NOT INSTALL KB3216755 if you don’t need it.  Huge memory leak reported to associated with this. If you need it I’d consider all my options.

UPDATE – GET KB3216755

As you can read it the comments, Microsoft reached out and confirms the issues are fixed as part of KB3216755 => https://support.microsoft.com/en-us/help/4011347/windows-10-update-kb3216755 . I commend them for responding so quickly and getting it sorted. Do not that at the time of writing this (late on January 30th CET) the Windows Sever 2016 update isn’t in the Windows Catalog yet, only the Windows 10 ones. But Microsoft confirms you should install the update  on their blog

Windows Server 2016 Data Deduplication users: please install KB3216755!

The issue

Good morning. A quick blog post to give a heads up to my readers who might not be subscribed to Anton Gostev (Veeam) his “The Word Form Gostev”. It concerns a warning on Windows Server 2016 Deduplication corruption.

Warning on Windows Server 2016 Deduplication Corruption

There are multiple reports of data corruption with Windows Server 2016 deduplication. One is related to file sizes over 2TB. The other with the loss of checksum values. Microsoft is aware these issues and a fix is coming for these issues.

I quote Gostev

I’ve already received the official confirmation from Microsoft that this is the know issue (ID 10165851) which is scheduled to be addressed in the next Windows Server 2016 servicing update. There are actually two separate issues, both leading to file corruption when using deduplication on very large files. One issue occurs when files grow to 2.2TB or larger, and another one causes loss of checksums for files with “smaller sizes” – this is the actual wording of the official note, so I have no idea how small

What to do?

If you use Windows Server 2016 deduplication for backups, create new full backups regularly. Also make sure you do backup integrity testing and restore tests. Follow up on the update when it arrives.

If you use the for production data make sure you have frequent and validated backups! Design & operate under the mantra of “Trust but verify”.

Also, we’ve heard reports and noticed that Windows Server 2016 Deduplication resource configuration isn’t always respected. I.e. it can take all resources away despite limitations being set. We hope a fix for this is also under way.

Hyper-V Amigos Showcast Episode 12–ReFS v3.1 and Backup

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In this Episode Carsten and I look at a single host deployment with Storage Spaces on Windows Server 2016. We create a “Hybrid” disk just like in Storage Spaces Direct by combining SSD & HDD in a storage Tier. We were very happy to discover that ReFSv3.1 does real time tiering.

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We’re very excited about this because we want to leverage the benefits if Veeam Backup & Replication 9.5 brings by leveraging ReFSv3.1 (Block Cloning) in regards to backup transformation actions and Grandfather-Father-Son (GFS) spaces savings. To do so we’re looking at our options to get these benefits and capabilities leveraging affordable yet performant storage for our backup targets. S2D is one such option but might be cost prohibitive or overkill in certain environments.

ReFS v3.1 on non-clustered Windows Server 2016 hosts bring us integrity streaming, file corruption repair with instant recovery as protection against bit rot, the performance of tiered storage and SMB3 as a backup target at a great price point.

We encourage you to watch the video and see for yourself. As always, we had fun and hope your can learn something together with us, the Hyper-V Amigos Smile

VeeamOn 2017 Call for Presentations

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Veeam will be holding its annual conference VeeamOn 2017 in New Orleans, Louisiana on May 16th – 18th. You can actually already pre-register for the conference today. Just follow this link. This qualifies you for a 200$ discount.

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But don’t stop there. When you work with Veeam products you might have some interesting solutions and experiences to share. Maybe you got creative and designed a smart solution to you needs. That’s something that can inspire people to think about how they use the products. So please, don’t be shy. Consider submitting your proposal for a presentation at VeeamOn 2017. Help your peers to achieve their needed availability in an always-on world. Go to https://www.veeam.com/veeamon/call-for-presentations and share your experience, knowledge and insights.

I hope to see you there to learn form and be inspired by you, my peers and colleagues from all over the world!

Veeam Leads the way by leveraging ReFS v3 capabilities

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Introduction

You might have noticed that I’m pretty impressed by what Microsoft is doing with ReFS v3 in Windows Server 2016. You can read some of my musing on it in ReFS vNext Block Cloning and ODX and take a look at a comparison between ReFS & ODX speeds when creating VHDX files in Lightning Fast Fixed VHDX File Creation Speed With ReFS on Windows Server 2016 .

Note that this is also leveraged for accelerated checkpoint merges, VHDX resizing etc.

Now it goes without saying that Hyper-V (they’re the tip of the spear at MSFT) and other Microsoft products would take advantage of the capabilities of ReFS. But now we know that Veeam Backup & Replication 9.5 has made use of ReFS to help with the resilience of their backups, the speed of their Synthetic Full backups and the space required.

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To a Hyper-V MVP and a Veeam vanguard it was obvious these two combined just had to lead to way for others to follow.

Veeam Leads the way by leveraging ReFS v3 capabilities

Veeam Backup & Replication 9.5 will leverage ReFS v3 …

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and by doing so they deliver the following benefits:

  • Shorted backup windows and a reduced backup storage load on the repository
  • Reduced backup target storage capacity which is reducing or eliminating the need for deduplication in many scenarios.
  • Better backup data protection by leveraging the ReFS native capabilities to protect against bit rot which was one of the prime goals for which Microsoft designed ReFS.

How is this done?

ReFS v3 has “fast cloning” technology which Veeam is leveraging. This results in up to 10 times  faster creation and transformation of synthetic full backup files!  ReFS fast cloning allows for creating new files without physically moving data blocks between files. This is what delivers even shorter backup windows and lower backup storage load on the repository or repositories.

They use what they call “Spaceless full backup technology” which allows multiple full backup files to reside on the same ReFS volume that share the same physical data blocks. As a result they need less storage capacity which can reduce or eliminate the need (and cost) of deduplication appliances whilst leveraging commodity storage.

Lest see how this is done. A “legacy” full backup is created an consumes 30% storage capacity. Then we make incremental backups.

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3 incremental backups add 3 * 10% of delta to the needed backup storage capacity which adds up to 60%.

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We create a synthetic full backup and the copies of the data require another 30% of space (90%). 

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No let’s compare this to v9.5 that leverages a Windows Server 2016 ReFS formatted backup target repository. Instead of copying data ReFS references already existing data block for a new file. This saves on IO, space and time!

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Is this safe? What if those data blocks that are reference multiple times are corrupted? Well Veeam does have protection against that in place already! But it goes the extra mile as ReFS has the capabilities to protect against that itself or it’s power would also become its biggest weakness.

Veeam’s data integrity streams integration leverages ReFS data integrity scanner and even proactive error correction when used in combination with Storage Spaces to protect backup files from bit rot and allows for more reliable forever-incremental archiving. This helps make the spaceless full backup technology trustworthy & safe alongside the health checking & error fixing capabilities already available in Veeam Backup & Replication.

Conclusion

I’m impressed by the forward looking and fast adoption of the capabilities of ReFS v3 by Veeam and I’m testing Backup & Replication v9.5 Beta today in the lab. They have more up their sleeve by the way as they have some interesting work with PowerShell Direct to make backups ever more resilient in ever more scenarios. More on that later.

Anyone who said Veeam would lose its edge in the world of Hyper-V backups when Microsoft introduced their own native change block tracking (resilient change tracking) has clearly never dealt with Veeam seriously and professionally. I have and I’m always happy to chat to them as they have serious technical skills combined with vision and business acumen that makes sure they’re leaders in the business of backup. It makes me proud to be a Veeam vanguard and a MVP with a specialization in Hyper-V.