What Capacity Utilization Will I have after I Evacuate a vSAN Host?

To fully evacuate a vSAN host and satisfy FTT=1, FTM=RAID1 you must have at least 4 hosts in the cluster. When a host is put in maintenance mode and fully evacuated, that host data is spread across the surviving hosts. In other words, if you follow the vSAN best practice guidance to stay less than or equal to 70% utilized, then the capacity that represents the 70% utilization must now fit on 3 hosts, which means those 3 hosts become 93% utilized (70% utilized * 4 nodes / 3 nodes = 93.3% utilized). The more hosts you have in the cluster, the less utilized your cluster will be when putting a host in maintenance mode. For example: 70% utilized * 10 nodes / 9 nodes = 77.7% utilized after evacuation of a host.

The formula for this is:

% Utilization after evacuation = (% Utilization before evacuation * # nodes) / (# nodes – 1)

Nearly 10,000 vSAN Customers! Come hear from 4 of them at VMworld 2017!

I started at VMware on the vSAN team 4 years ago when we had 0 customers. It’s been a pretty wild and fun ride to get to 10,000 but we’ve only just begun. Customers are seeing the benefits of HCI and vSAN for all sorts of use cases including mission critical applications, management clusters, VDI, ROBO, DMZ, test/dev, DR Sites, and IaaS at IBM Bluemix (formerly SoftLayer) and soon at Amazon with VMware Cloud on AWS.

Unfortunately, we cannot fit all 10,000 customers in one breakout session at VMworld, but we can fit 4. I’m hosting a breakout session titled:

vSAN Technical Customer Panel [STO2615PU]

(Now that the session has happened, here is the video recording:)

I hosted a similar session last year with Stanley Black and Decker, Synergent Bank, M&T Bank, and Baystate Health and it was a lot of fun with some great audience participation. For more information check here.

This year we are fortunate to have Sanofi, Sekisui, Travelers, and Herbalife join the panel. The format is this:

  • Introduce the Panel
  • Panelists introduce their company, their VMware environment, and their use of vSAN
  • Q&A – I will have some questions for the panel but we expect the audience questions to generate some great discussion.

Let’s meet the Panelists:

Joachim Heppner
Director, Virtualization Engineering Services
Sanofi

In 2016 this large pharma needed to refresh their Remote Office Branch Office (ROBO) sites. After a successful proof of concept, 2+ Node vSAN on HPE ProLiant Servers was chosen. Since then, vSAN has been deployed for management clusters and VDI in USA and EMEA as well as in 2 of their 13 regional data centers. Next, Cloud Foundation is being considered to replace their legacy Blade servers & Storage arrays.

Michael DiBenedetto
Director, Global IT
Sekisui Diagnostics

In early 2014 this mid-size pharma needed to build a DR site and chose a 4 Node vSphere cluster with vSAN enabled. They used vSphere Replication and SRM to test and automate DR. They also moved their test and development environment to this cluster. This year they are replacing their production data center with HCI and vSAN.

Alexander Szwez
Senior Systems Engineer
Travelers

vSAN was chosen to support production and test/dev Hadoop workloads. Two other vSAN clusters are used for new application workload POC’s. In addition, 2 Cloud Foundation configurations, each with a management cluster and a VM workload cluster are being implemented to prove how the built-in automation simplifies operations.

Jaime Gurrola
Worldwide Manager of Linux & VMWare
Herbalife International of America

In early 2014 this nutrition company wanted to modernize their data center by automating IT to simplify application access and management and transform Windows delivery. Today they run vSphere and vSAN and are evaluating NSX in multiple call centers to support 4000 Horizon VDI across 5 ROBO sites and their primary data centers for mission critical applications. They’ve achieved great cost savings resulting in significantly reduced TCO while delivering exceptional performance to their users.

I’m looking forward to seeing many great friends and to meet new ones at VMworld. I hope you can come and participate and enjoy this session with these great guests.

Replays of Virtual SAN Sessions at VMworld 2016 That You Didn’t Want to Miss

What a great week last week at VMworld 2016. I had many good meetings with customers, participated in 3 breakout sessions, met up with some old friends and met some new ones. If you missed VMworld, well, then you missed a bunch of great sessions. There’s no way you could have seen them all, so, VMware has made them available here: http://www.vmworld.com/en/sessions/2016.html.

I participated in two sessions:

The first one was a customer panel discussion on Tuesday afternoon. I need to thank Glenn Brown from Stanley Black & Decker, Mike Caruso from Synergent, Tom Cronin from M&T Bank, and Andrew Schilling from Baystate Health who all did a fantastic job representing themselves, their companies, and their use of Virtual SAN. We had great interaction from the audience with lots of good questions. For a replay of the session check this out:

Four Unique Enterprise Customers Deployment of VMware Virtual SAN [STO7560]
Glen Brown
, System Engineer, Stanley Black and Decker
Michael Caruso, AVP Corporate Information Systems, Synergent
Tom Cronin, Sr. Staff Specialist – Platforms Engineering Group, M&T Bank
Frank Gesino, Senior Technical Account Manager, VMware
Andrew Schilling, Team Leader – IT Infrastructure, Baystate Health Inc.
Tuesday, Aug 30, 5:00 p.m. – 6:00 p.m.

The other session I was involved in was on Wednesday and repeated on Thursday. I had the good fortune to present with two VSAN Product Managers who are responsible for making VSAN great. Vahid Fereydounkolahi is responsible for driving new features into the VSAN product and Rakesh Radhakrishnan is responsible for making sure all the vendor hardware components are properly qualified for VSAN and for looking out into the future of new technologies like NVMe and RDMA to adopt into VSAN. For a replay of the two sessions check these out:

Peter Keilty, Office of the CTO, Americas Field – Storage and Availability, VMware, Inc.
Rakesh Radhakrishnan, Product Management & Strategy Leader, VMware
Wednesday, Aug 31, 2:00 p.m. – 3:00 p.m.
Vahid Fereydounkolahi kicked this one off discussion VSAN features, capabilities, and how it works, I took over in the middle to discuss Day 2 operations, and Rakesh Radhakrishnan finished it off discussing the Ready Node program as well as current and future flash and IO technology that VSAN incorporates or will incorporate.
Virtual SAN Technical Deep Dive and What’s New [STO8246R]

Thursday, Sep 01, 10:30 a.m. – 11:30 a.m.
Vahid wasn’t able to make this time so I kicked things off talking about VSAN features, capabilities, how it works, and Day 2 operations, and Rakesh Radhakrishnan finished it off discussing the Ready Node program as well as current and future flash and IO technology that VSAN incorporates or will incorporate.
Virtual SAN Technical Deep Dive and What’s New [STO8246R]

In my previous blog post I highlighted the sessions you wouldn’t want to miss. So here, I’ll provide the links to those sessions. A few either haven’t been uploaded yet or won’t because of legal or future looking reasons:

Christos Karamanolis is literally the brains behind VSAN since its inception and our chief visionary for Storage. If you want the whole picture wrapped up in a 1 hour session, this is it.
An Industry Roadmap: From storage to data management [STO7903]
Christos Karamanolis, VMware Fellow – CTO of Storage and Availability, VMware
Wednesday, Aug 31, 4:00 p.m. – 5:00 p.m.

Continue reading “Replays of Virtual SAN Sessions at VMworld 2016 That You Didn’t Want to Miss”

Virtual SAN Sessions You Won’t Want to Miss at VMworld 2016

Shameless self-promotion here. I’m very excited to be presenting 2 sessions at the upcoming VMworld 2016 in Las Vegas. So, of course I think you shouldn’t miss them. The first is a customer panel session that I’ll be hosting. I’ve worked with each of these customers who have had VSAN running production workloads for well over a year. Everything wasn’t always perfect, but, they continue to expand their usage of VSAN in their data centers. In two of the customers, they are now standardized on VSAN for any new workloads. These customers will provide an overview of their deployments, answer some of my questions, then take questions from the audience.

Four Unique Enterprise Customers Deployment of VMware Virtual SAN [STO7560]
Glen Brown, System Engineer, Stanley Black and Decker
Michael Caruso, AVP Corporate Information Systems, Synergent
Tom Cronin, Sr. Staff Specialist – Platforms Engineering Group, M&T Bank
Frank Gesino, Senior Technical Account Manager, VMware
Andrew Schilling, Team Leader – IT Infrastructure, Baystate Health Inc.
Tuesday, Aug 30, 5:00 p.m. – 6:00 p.m.

This VSAN Deep Dive session will cover features of the latest VSAN release, how they work, and some best practices for deploying VSAN. I’ll be presenting along with our lead VSAN Product Managers. This session will be held on two different days.

Virtual SAN Technical Deep Dive and What’s New [STO8246R]
Peter Keilty, Office of the CTO, Americas Field – Storage and Availability, VMware, Inc.
Rakesh Radhakrishnan, Product Management & Strategy Leader, VMware
Wednesday, Aug 31, 2:00 p.m. – 3:00 p.m.
Thursday, Sep 01, 10:30 a.m. – 11:30 a.m.

Other VSAN Sessions You Won’t Want to Miss

There are so many great VSAN sessions it’s hard to pick just a few. So, here are the ones I am most familiar with that I’m confident will be great. But that doesn’t mean that some of the others won’t be.

Christos Karamanolis is literally the brains behind VSAN since its inception and our chief visionary for Storage. If you want the whole picture wrapped up in a 1 hour session, this is it.

An Industry Roadmap: From storage to data management [STO7903]
Christos Karamanolis, VMware Fellow – CTO of Storage and Availability, VMware
Wednesday, Aug 31, 4:00 p.m. – 5:00 p.m.

Continue reading “Virtual SAN Sessions You Won’t Want to Miss at VMworld 2016”

2-Node Virtual SAN Software Defined Self Healing

I continue to think one of the hidden gem features of VMware Virtual SAN (VSAN) is its software defined self healing ability.  I recently received a request for a description of 2-Node self healing. I wrote about our self healing capabilities for 3-Node, 4-Node and more here. And I wrote about Virtual SAN 6 Rack Awareness Software Defined Self Healing with Failure Domains here. I suggest you check out both before reading the rest of this. I also suggest you check out these two posts on 2-Node VSAN for a description on how they work here and are licensed here.

For VSAN, protection levels can be defined through VMware’s Storage Policy Based Management (SPBM) which is built into vSphere and managed through vCenter.  VM objects can be assigned to different policy which dictates the protection level they receive on VSAN. With a 2-Node Virtual SAN there is only one option for protection, which is the default # Failures To Tolerate (#FTT) equal to 1 using RAID1 mirroring. In other words, each VM will write to both hosts, if one fails, the data exists on the other host and is accessible as long as the VSAN Witness VM is available.

Now that we support 2-Node VSAN, the smallest VSAN configuration possible is 2 physical nodes with 1 caching device (SSD, PCIe, or NVMe) and 1 capacity device (HDD, SSD, PCIe, or NVMe) each and one virtual node (VSAN Witness VM) to hold all the witness components. Let’s focus on a single VM with the default # Failures To Tolerate (#FTT) equal to 1.  A VM has at least 3 objects (namespace, swap, vmdk).  Each object has at least 3 components (data mirror 1, data mirror 2, witness) to satisfy #FTT=1.  Lets just focus on the vmdk object and say that the VM sits on host 1 with mirror components of its vmdk data on host 1 and 2 and the witness component on the virtual Witness VM (host 3).

01 - 2-Node VSAN min

OK, lets start causing some trouble.  With the default # Failures To Tolerate equal 1, VM data on VSAN should be available if a single caching device, a single capacity device, or an entire host fails.  If a single capacity device fails, lets say the one on esxi-02, no problem, another copy of the vmdk is available on esxi-01 and the witness is available on the Witness VM so all is good.  There is no outage, no downtime, VSAN has tolerated 1 failure causing loss of one mirror, and VSAN is doing its job per the defined policy and providing access to the remaining mirror copy of data.  Each object has more that 50% of its components available (one mirror and witness are 2 out of 3 i.e. 66% of the components available) so data will continue to be available unless there is a 2nd failure of either the caching device, capacity device, or esxi-01 host.  The situation is the same if the caching device on esxi-02 fails or the whole host esxi-02 fails. VM data on VSAN would still be available and accessible. If the VM happened to be running on esxi-02 then HA would fail it over to esxi-01 and data would be available. In this configuration, there is no automatic self healing because there’s no where to self heal to. Host esxi-02 would need to be repaired or replaced in order for self healing to kick in and get back to compliance with both mirrors and witness components available.

02 - 2-Node VSAN min

Self healing upon repair

How can we get back to the point where we are able to tolerate another failure?  We must repair or replace the failed caching device, capacity device, or failed host.  Once repaired or replaced, data will resync, and the VSAN Datastore will be back to compliance where it could then tolerate one failure.  With this minimum VSAN configuration, self healing happens only when the failed component is repaired or replaced.

03 - 2-Node VSAN min

2-Node VSAN Self Healing Within Hosts and Across Cluster

To get self healing within hosts and across the hosts in the cluster you must configure your hosts with more disks. Let’s investigate what happens when there are 2 SSD and 4 HDD per host and 4 hosts in a cluster and the policy is set to # Failures To Tolerate equal 1 using the RAID 1 (mirroring) protection method.

01~ - 2-Node VSAN.png

If one of the capacity devices on esxi-02 fails then VSAN could chose to self heal to:

  1. Other disks in the same disk group
  2. Other disks on other disk groups on the same host

The green disks in the diagram below are eligible targets for the new instant mirror copy of the vmdk:

02~ - 2-Node VSAN

This is not an all encompassing and thorough explanation of all the possible scenarios.  There are dependencies on how large the vmdk is, how much spare capacity is available on the disks, and other factors.  But, this should give you a good idea of how failures are tolerated and how self healing can kick in to get back to policy compliance.

Self Healing When SSD Fails

If there is a failure of the caching device on esxi-02 that supports the capacity devices that contain the mirror copy of the vmdk then VSAN could chose to self heal to:

  1. Other disks on other disk groups on the same host
  2. Other disks on other disk groups on other hosts.

The green disks in the diagram below are eligible targets for the new instant mirror of the vmdk:

03~ - 2-Node VSAN.png

Self Healing When a Host Fails

If there is a failure of a host (e.g. esxi-02) that supports mirror of the vmdk then VSAN cannot self heal until the host is repaired or replaced.

04~ - 2-Node VSAN

Summary

VMware Virtual SAN leverages all the disks on all the hosts in the VSAN datastore to self heal.  Note that I’ve only discussed above the self healing behavior of one VM but other VM’s on other hosts may have data on the same failed disk(s) but their mirror may be on different disks in the cluster and VSAN might choose to self heal to other different disks in the cluster.  Thus the self healing workload is a many-to-many operation and thus spread around all the disks in the VSAN datastore.

Self healing is enabled by default, behavior is dependent on the software defined protection policy (#FTT setting), and can occur to disks in the same disk group, to other disk groups on the same host, or to other disks on other hosts. The availability and self healing properties make VSAN a robust storage solution for all data center applications.

VSAN In 3 Minutes Series

These are so cool I had to recognize them. If you are like me and would rather see things in action than read about them in a manual, then the VSAN In 3 Minutes Series is for you.

VSAN in 3 Minutes Series

Check the videos out. A big shout out to my colleague Greg Mulholland who does a great job putting these together.

VMware Virtual SAN at Storage Field Day 9 (SFD9) – Making Storage Great Again!

On Friday, March 18 I took the opportunity to watch the live Webcast of Storage Field Day 9. If you can carve our some time, I highly recommend this.

Tech Field Day‎@TechFieldDay
VMware Storage Presents at Storage Field Day 9

The panel of industry experts ask all the tough questions and the great VMware Storage team answers them all.

Storage Industry Experts VMware Virtual SAN Experts
  • Alex Galbraith @AlexGalbraith
  • Chris M Evans @ChrisMEvans
  • Dave Henry @DaveMHenry
  • Enrico Signoretti @ESignoretti
  • Howard Marks @DeepStorageNet
  • Justin Warren @JPWarren
  • Mark May @CincyStorage
  • Matthew Leib @MBLeib
  • Richard Arnold @3ParDude
  • Scott D. Lowe @OtherScottLowe
  • Vipin V.K. @VipinVK111
  • W. Curtis Preston @WCPreston
  • Yanbing Le @ybhighheels
  • Christos Karamanolis @XtosK
  • Rawlinson Rivera @PunchingClouds
  • Vahid Fereydouny @vahidfk
  • Gaetan Castelein @gcastelein1
  • Anita Kibunguchy @kibuanita

 

The ~2 hour presentation was broken up into easily consumable chunks. Here’s a breakdown or the recoded session:

VMware Virtual SAN Overview

In this Introduction, Yanbing Le, Senior Vice President and General Manager, Storage and Availability, discusses VMware’s company success, the state of the storage market, and the success of HCI market leading Virtual SAN in over 3000 customers.

What Is VMware Virtual SAN?

Christos Karamanolis, CTO, Storage and Availability BU, jumps into how Virtual SAN works, answers questions on the use of high endurance and commodity SSD, and how Virtual SAN service levels can be managed through VMware’s common control plane – Storage Policy Based Management.

VMware Virtual SAN 6.2 Features and Enhancements

Christos continues the discussion around VSAN features as they’ve progressed from the 1st generation Virtual SAN released in March 12, 2014 to the 2nd, 3rd, and now 4th generation Virtual SAN that was just released March 16, 2016. The discussion in this section focuses a lot on data protection features like stretched clustering and vSphere Replication. They dove deep into how vSphere Replication can deliver application consistent protection as well as a true 5 minute RPO based on the built in intelligent scheduler sending the data deltas within the 5 minute window, monitoring the SLAs, and alerting if they cannot be met due to network issues.

VMware Virtual SAN Space Efficiency

Deduplication, Compression, Distributed RAID 5 & 6 Erasure Coding are all now available to all flash Virtual SAN configurations. Christos provides the skinny on all these data reduction space efficiency features and how enabling these add very little overhead on the vSphere hosts. Rawlinson chimes on the automated way Virtual SAN can build the cluster of disks and disk groups that deliver the capacity for the shared VSAN datastore. These can certainly be built manually but VMware’s design goal is to make the storage system as automated as possible. The conversation moves to checksum and how Virtual SAN is protecting the integrity of data on disks.

VMware Virtual SAN Performance

OK, this part was incredible! Christos laid down the gauntlet, so to speak. He presented the data behind the testing that shows minimal impact on the hosts when enabling the space efficiency features. Also, he presents performance data for OLTP workloads, VDI, Oracle RACK, etc. All cards on the table here. I can’t begin to summarize, you’ll just need to watch.

VMware Virtual SAN Operational Model

Rawlinson Rivera takes over and does what he does best, throwing all caution to the wind and delivering live demonstrations. He showed the Virtual SAN Health Check and the new Virtual SAN Performance Monitoring and Capacity Management views built into the vSphere Web Client. Towards the end, Howard Marks asked about supporting future Intel NVMe capabilities and Christos’s response was that it’s safe to say VMware is working closely with Intel on ensuring the VMware storage stack can utilize the next generation devices. Virtual SAN already supports the Intel P3700 and P3600 NVMe devices.

This was such a great session I thought I’d promote it and make it easy to check it out. By the way, here’s Rawlinson wearing a special hat!

Make Storage Great Again