VSAN 6.2 Performance Degradation (Hybrid)

In vSAN (not misspelled) 6.2, dedup and compression was introduced. These features; however, only apply to all-flash configurations and must not be set up on Hybrid environments.

Some customers have experienced performance degradation on 6.2 Hybrid environments when compared to 6.0 or 6.1 performance. Read caching performance degradation can be observed for Hybrid Disk Groups on the SSD cache tier, due to a low level scanning for unique blocks (dedup). Although this is normal for All-Flash environments, it is important to check your hosts participating on a Hybrid Cluster, to make sure this is turned OFF.

To check/change this option, you can use the ESXi Shell or PowerCli.

The setting would show “2” if it is turned ON, and “0” if it is turned OFF. It should be set to “0” for EACH Hybrid host.

Check Setting

ESXi Shell – esxcfg-advcfg -g /LSOM/lsomComponentDedupScanType 




PowerCli – Get-VMHost<HostName> | Get-AdvancedSetting –Name LSOM.lsomComponentDedupScanType





Change Setting

ESXi Shell – esxcfg-advcfg -s 0 /LSOM/lsomComponentDedupScanType 




PowerCli – Get-VMHost <HostName> | Get-AdvancedSetting -Name LSOM.lsomComponentDedupScanType | Set-AdvancedSetting -Value “0”



Using PowerCli is my preference, since you won’t have to enable SSH on the hosts, and you can use wildcards to check/change all the hosts with little effort.

VSAN Proactive Rebalance

balance1There has been a lot of questions as to what happens when a rebalance task is triggered in VSAN. By default, VSAN will try to do a proactive rebalance of the objects as the disks start hitting certain thresholds (80%). There are instances, during failures/rebuilds, or even when organic imbalance is discovered, where administrators may trigger a proactive rebalance task.

What happens

Once you click on the “balance disks” button. You are opening a 24-hr window where rebalance will take place. This means that the rebalance operation may take up to 24 hours, so be patient. Many people have voiced frustration because the UI shows a 5% progress (or lack there of) for a very long time, almost appearing as it is stuck. The rebalance is taking place on the background.

You may also not see any progress at all for the first 30 minutes. This is because VSAN wants to wait to make sure that the imbalance persists before it attempts to move any objects around. After all, the rebalance task is moving objects between disks/nodes, so copying data over the network will take resources, bandwidth and time; so plan accordingly if you must rebalance.

Notice that if your disks are balanced, the button is greyed out to avoid unnecessary object “shuffling”.



My Move to VMware: The Road Ahead

vmwareI am happy to announce that I’m joining VMware as a Storage Solutions Architect. Although I am a little sad to leave my prior employer (High Availability Inc.), I am very excited for what the future holds.


I will be focusing on… yes, you guessed it, Virtual SAN. For those that know me, you know that this is “my thing”. I am one that makes educated decisions and calculated risks, and joining the VSAN team during these exciting times is a move I’m more than happy to make.

As a partner, I’ve seen the growing interest on VSAN as well as its adoption on businesses of all sizes. Having been part of large VSAN implementations in the past, I am looking forward to focusing on this technology, and expanding my knowledge base on all things VMware.

I would like to thank Steve at High Availability Inc. for being a super cool boss, and I wish them the best on their fast growth as a top notch VAR.

I’m looking forward to working with old acquaintances such as John Nicholson and Pete Flecha (Virtually Speaking Podcast guys), as well as the rest of the VSAN team.



VMworld ’16 TFDx: PrimaryData

pd_logoAt VMworld 2016 TechField Day extra, PrimaryData announced the launch of DataSphere allowing for simplified management and orchestration, as well as increased application uptime, and ability to scale out any storage vendor.

To be honest, I was not familiar with PrimaryData before TFDx; however, I can see say that there is a future for this technology.

What does PrimaryData bring to the table?

Well, to put it in simple terms, PrimaryData does to storage what VMware did to compute. Yes, PrimaryData virtualizes the data and is able to decouple the data from silo storage arrays, allowing admins to move data between different storage vendors with little to no downtime. PrimaryData is a software solution, so it can be deployed as an OVA or on physical hardware.

This is very powerful, in my humble opinion. I have spent the last year and a half moving customers from NetApp 7-mode to clustered mode. If the customers run VMware, then moves are as easy as a storage vMotion, but other workloads for NAS and SAN can be tricky, mainly because customers are not allowed to have downtime. Although NetApp has a tool called 7MTT, it is ok for basic moves, but not very user friendly to the point where customers require PS in order to be able to use.

I would love to see PrimaryData involved for NetApp migrations. I think this will make the adoption to clustered mode more enticing, faster, and easier.

Aside from migrations, you can look at this solution as a way to tier your data among different vendors and types of media. You can do automatic tiering based on objectives, and the software is smart enough to move your data for compliance of such objectives, whether it is on different storage vendors or the cloud.

PrimaryData works with VMware’s VSAN AND VVols, how cool is that?!?!?

Definitely check them out. This is a technology everyone should keep their eye on…



Check out their TFDx presentation here


VMworld ’16 TFDx: Ops view of Docker


I was fortunate to participate at VMworld’s 2016 Tech Field Day (extra (TFDx)). One of the presenters was Mike Coleman from Docker.

This presentation was, in my opinion, properly steered towards the correct crowd to get docker in the operations side of the house. Docker has been around for a while now, but the adoption seems to be solely focused on the developer side, which is fine, but the operations side needs to buy into it, if Docker wants to bleed into Enterprise and SMB environments.

Once you deploy an app, the developers build task is completed and now becomes an operational task, aside from updates and such.

This is a great presentation for those that keep hearing about Docker, but have not had the time to read up on it. Starting from a 101 of what Docker is, how it is deployed, and tools to manage.

Few highlights:

  • Containers are not VMs
  • Containers share Kernel
  • VMs are houses (own plumbing, own electric, etc)
  • Containers are Apartments (shared resources like plumbing)
  • Docker engine runs on top of OS
  • It can be run on Physical or Virtual






Again, whether you are a Docker newbie or just curious, you should definitely check out this presentation about Docker.

You can find the Docker videos at the Tech Field Day Website