Tag Archives: SMB 3.0

MS Exchange on Nutanix now a MS validated ESRP solution

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I am pleased to announce that Nutanix has successfully completed the Microsoft Exchange Solution Review Program requirements and are now listed as a validated solution at the following URL:

Exchange Solution Reviewed Program (ESRP) – Storage

The solution shows a dual site 24,000 1GB Mailbox solution running on just 8 NX-8150 nodes. This is a very highly resilient solution with N+1 availability at each site allowing for full self healing and failover in the event of a node failure.

Nutanix is also the FIRST and only hyper-converged platform to be validated under ESRP, further strengthening our leadership in the market.

The performance testing (using Jetstress) was with the nodes at around 90% capacity with 8.5TB per node, proving that Nutanix provided great performance even when running at high utilization and where the working set far exceeds the SSD tier. This is key to a truly enterprise solution for a business critical application such as Exchange.

The solution is running on Hyper-V with SMB 3.0 on the underlying Nutanix Distributed Storage Fabric. The same solution can also be deployed on vSphere or Acropolis Hypervisors using iSCSI in a fully supported configuration.

The above solution was validated without using Compression or Erasure Coding both of which improve performance and give significant capacity savings which allows for larger mailboxes. As a result, the Nutanix platform provides even more value than the ESRP submission shows.

If there was any doubt around if you should virtualize MS Exchange on Nutanix platform, the fact Nutanix is now validated by Microsoft should put your mind at ease.

Now you can move one step closer to a fully webscale datacenter by removing another application specific silo and enjoy improved resiliency/performance while reducing operational cost and complexity.

Fight the FUD – Support for MS Exchange on Nutanix

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Its disappointing that some vendors have so little respect for customers time that they continue to spread FUD (Fear Uncertainty and Doubt) about other vendors products.

This post is for existing and future Nutanix customers to get the facts about support for MS Exchange on Nutanix.

First of all, Nutanix Distributed File System (NDFS) is not Network File System (NFS).

NDFS is a file system which presents storage to hypervisors (ESXi, Hyper-V and Acropolis Hypervisor) via industry standard storage protocols being iSCSI, SMB 3.0 and NFS.

Currently Microsoft do not support Exchange running with VMDKs hosted on NFS for Exchange deployments on vSphere, this is due to an outdated and baseless support policy which experts from almost every major storage vendor agree.

For more information see the below article:

Virtualizing Exchange on vSphere with NFS backed storage?

However Nutanix have a published KB providing full support for MS Exchange when running within VMDKs on NFS datastores.

Nutanix aims to provide an Uncompromisingly Simple solution for customers which gives them maximum flexibility/choice. As such, when deploying applications such as MS Exchange on Nutanix, how the application/s are deployed and what storage protocol they use is ultimately the customers choice.

The below are some of the benefits of this include:

  1. Running a standard platform and storage protocol for all workloads is a simple model which reduces the unnecessary complexity of multiple protocols and/or in-guest storage configurations.
  2. The customer has the choice to deploy in multiple configurations to suit their specific requirements
If you want to run a 100% Microsoft supported Exchange configuration on Nutanix you currently have two options:
  1. vSphere running iSCSI
  2. Hyper-V running SMB 3.0
  3. Acropolis Hypervisor (AHV) running iSCSI (default)

If you understand that NFS datastores are not supported by Microsoft, but accept it is fully supported by Nutanix and you want to run Exchange in a VMDK on NFS datastores, then Nutanix will support for MS Exchange and Microsoft will provide commercially reasonable support directly or via TSAnet if the case needs to be escalated.

So there you have it, MS Exchange can be ran on Nutanix in 100% Microsoft supported configurations and Nutanix customers have the choice in how they wish to deploy with full support from Nutanix.

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Related Articles:

Integrity of I/O for VMs on NFS Datastores – Part 4 – Torn Writes

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This is the fourth part of a series of posts covering how the Integrity of Write I/O is ensured for Virtual Machines when writing to VMDK/s (Virtual SCSI Hard Drives) running on NFS datastores presented via VMware’s ESXi hypervisor as a “Datastore”.

This part will focus on Torn Write I/O.

As a reminder from the first post, this post is not talking about presenting NFS direct to Windows.

Some of you are probably wondering “What is a Torn Write”?

A Torn write can occur if there is a problem (e.g.: Power or HW failure) during a multi sector block being written.

The below shows what a Torn Write looks like, which is basically where part of data A and B remain after a Torn write, resulting in corrupted data.

Torn Write

Image Source: Silent data corruption in disk arrays: A solution

The article Toward I/O-Efficient Protection Against Silent Data Corruptions in RAID Arrays describes a Torn Write (I/O) as:

Torn write: When a disk write is issued to a chunk, only a
portion of sectors in the chunk are successfully updated,
and the chunk contains some stale sectors in the end part.

The issue with the write I/O being written across multiple sectors is that in the event a power outage impacting the write back cache or a hardware issue such as a drive failing, the I/O may be partially written (or “Torn”). This means the data was not fully written, but some data was written overwriting the existing data causing corruption.

In this case, if the storage solution provides a write acknowledgement and the data is partially or not written to persistent media this results in what is known as silent data corruption as data being read back will be part of the new data and part of the old data.

It should be noted RAID does not protect against Torn writes, nor can it help correct the situation once it has occurred.

The next question is, does the issue of Torn writes impact VMs on ESXi backed by NFS datastores. The answer is, Yes because Torn Writes can potentially occur on any storage solution regardless of the abstracted storage protocol.

So do Torn Writes occur VMs on ESXi backed by NFS datastores? The answer again would be Yes, but importantly, this would not be as a result of anything at the hypervisor layer, it would be as a result of a failure impacting the underlying storage.

Note: This issue equally impacts block and file based storage presented to ESXi, so it is not a NFS specific issue.

So what is required to provide protection against Torn Writes?

The best method to protect against Torn Writes is to use checksums, specifically Block level checksums which can check the integrity of writes which span multiple sectors, therefore in the event of a torn write, the checksum will fail and a write acknowledgement will not be sent. The important fact here is the underlying storage is responsible for this process, not ESXi , the VMDK or storage protocol (FC,FCoE,iSCSI, NFS!) presenting the storage to ESXi.

In summary, Torn Writes are not an issue with VMs running on ESXi backed by NFS datastores where the underlying storage performs Block level checksums.

I have requested VMware create a Knowledge base article on Torn Writes for formal reference and will update this post with the reference if/when this is done.

In part five, I will discuss Data Corruption.

Integrity of Write I/O for VMs on NFS Datastores Series

Part 1 – Emulation of the SCSI Protocol
Part 2 – Forced Unit Access (FUA) & Write Through
Part 3 – Write Ordering
Part 4 – Torn Writes
Part 5 – Data Corruption

Nutanix Specific Articles

Part 6 – Emulation of the SCSI Protocol (Coming soon)
Part 7 – Forced Unit Access (FUA) & Write Through (Coming soon)
Part 8 – Write Ordering (Coming soon)
Part 9 – Torn I/O Protection (Coming soon)
Part 10 – Data Corruption (Coming soon)

Related Articles

1. What does Exchange running in a VMDK on NFS datastore look like to the Guest OS?
2. Support for Exchange Databases running within VMDKs on NFS datastores (TechNet)
3. Microsoft Exchange Improvements Suggestions Forum – Exchange on NFS/SMB
4. Virtualizing Exchange on vSphere with NFS backed storage