Improve vSphere Web Client Performance

I was always bothered by slow performance of my lab installation of vSphere Web Client (version 5.5). Although my lab is small I have large number of plugins. I use the Windows installable version which is running together with vCenter, Inventory service, Update Manager and database server.

I noticed that the Java process was using over 1 GB of RAM. The fix was simple – add more memory to the VM and to Web Client Tomcat server:

Edit wrapper.conf file which is located in C:\Program Files\VMware\Infrastructure\vSphereWebClient\server\bin\service\conf.

and increase

in the JVM Memory section. I increased the value to 3072m.


PVLAN-like Behavior with ACL on VXLAN Network

Private VLANs (PVLANs) are useful in multitenant environments where there is a need to provide access to single server for all customers while not allowing them to see each other and NAT or dedicated networks are not an option. Agent based backup with central backup server or VM monitoring are example of such use-cases.

There might be a constraint that does not allow the usage PVLAN. For example hardware that does not support it (Cisco UCS) or VXLAN logical network. The latter I used in one of my designs. There was a need for single backup network stretched over pods without L2 connectivity. VXLAN can overlay L3 fabric and thus create single network spanning the pods however VXLAN does not support PVLANs. If VMware NSX is used then distributed (in-kernel) firewall can be used instead. If vCloud Network and Security is providing the VXLAN networks then there is App Firewall (vShield App) which unfortunately provides significant performance and throughput hit as it is inspecting every packet/frame in user-space service VM. It also adds complexity to the solution.

Access Control Lists

As of vSphere 5.5 vSphere distributed switch (vDS) supports access control lists (ACL) at the portgroup level. The ACL configuration is available only via the vSphere Web Client in the vDS portgroup > Manage > Settings > Policies > Edit > Traffic filtering and marking section. The following configuration can be used to provide the similar behavior to private VLAN.

Rule 1: Allow VMs to Server

Action: Allow
Type: MAC
Protocol/Traffic type: any
VLAN ID: any
Source Address: any
Destination Address: MAC address of the promiscous server or router

Rule 2: Allow Server to VMs

Action: Allow
Type: MAC
Protocol/Traffic type: any
VLAN ID: any
Source Address: MAC address of the promiscous server or router
Destination Address: any

Rule 3: Allow ARP

Action: Allow
Type: MAC
Protocol/Traffic type: any
VLAN ID: any
Source Address: any
Destination Address: FF:FF:FF:FF:FF:FF

Rule 4: Drop all

Action: Drop
Type: MAC
Protocol/Traffic type: any
VLAN ID: any
Source Address: any
Destination Address: any

Screenshot of the final configuration:

ACL rules

Note: As with PVLANs there is still a security issue of the tenant misconfiguring VMs IP address and causing Denial-of-Service for another VM with the same IP address. There are ways to remediate it but out of scope of this article.


Monitor Wear and Tear of Your VSAN SSDs

As I started experimenting with VMware Virtual SAN (VSAN) in my lab and am using consumer grade SSDs which are not on VSAN (beta) HCL I am worried about wear and tear of the memory cells who have limited write endurance.

I wondered if it is possible to access the SMART attributes of the disks and quick search showed that there is a KB article 2040405 written which still applies although not specific to vSphere 5.5.

From the ESXi console run esxcli storage core device list to get list of storage devices and then run esxcli storage core device smart get -d device to get the SMART data.

This is output of my Intel 520 drive.

Intel 520 SMART Attributes


Unfortunately another host with OCZ SSD does not display any data with an error:

Error getting Smart Parameters: CANNOT open device


vMSC and vSphere HA Timeout?

I am currently working of vSphere Metro Cluster Design (vMCS) with NetApp MetroCluster. vMSC is basically a stretched vSphere HA cluster between two sites with some kind of clustered storage solution. The idea is to leverage vSphere HA and vMotion to achieve high SLAs for planned or unplanned downtime.

While researching and simulating all the failure scenarios there is one particular that must include manual step. When there is complete site failure the surviving storage controller cannot distinguish between site failure or just a network partition (split brain). NetApp MetroCluster offers Tie-Breaker that needs to be deployed in a third datacenter and acts as a witness to help the surviving controller to decide what to do.

NetApp MetroCluster with Tie-Breaker and Full Site Failure
NetApp MetroCluster with Tie-Breaker and Full Site Failure

If the third datacenter is not available and Tie-Breaker cannot be implemented the storage controller takes no action and the storage administrator needs to do manual forced takeover of the storage resources on the surviving controller.

I was wondering how will vSphere infrastructure react to this and what steps the vSphere administrator will need to take to recover the failed workloads. VMware white paper VMware vSphere Metro Storage Cluster Case Study actually mentions this scenarion and says:

NOTE: vSphere HA will stop attempting to start a virtual machine after 30 minutes by default. If the storage team has not issued the takeover command within that time frame, the vSphere administrator must manually start virtual machines when the storage is available.

I was wondering how to streamline the manual vSphere administrator process of registering and starting the failed virtual machines but to my surprise in my test lab even if the storage failover took more than an hour, vSphere HA happily restarted all the failed VMs.

What is actually happening can be observed in the FDM logs of the HA master node. When the site fails following log message is repeating every minute:

[4CD9EB90 info ‘Placement’] [RR::CreatePlacementRequest] 6 total VM with some excluded: 0 VM disabled; 0 VM being placed; 6 VM waiting resources; 0 VM in time delay;

The HA master node tried to find suitable hosts to restart the six failed VMs from the failed site. As none of the available host had yet access to the storage needed by those VMs it was retrying every minute. Once I failed over the storage  following messages immediately appeared:

[InventoryManagerImpl::ProcessVmCompatMatrixChange] Updating the existing compatibility matrix.

[VmOperationsManager::PerformPlacements] Sending a list of 6 VMs to the placement manager for placement.

The host to VM compatibility matrix was updated and immediately the placement manager found suitable hosts and HA restart process started.

This means you need not to worry about vSphere HA timeout. The timeout actually does not start ticking till the HA power on operation is attempted and then it takes 5 restart attempts in 0, 2 min, 6 min, 14 min and 30 minute time points.

P.S. Lee Dilworth and Duncan Epping actually had VMworld 2012 session about vMSC and this information is mentioned there.

Edit 8/8/2013

P.P.S. Duncan Epping blogged about HA and its dependence on compatibility matrix here.

vCloud Director 5.1 Features and their vSphere Dependency

I see more and more customers are migrating from vCloud Director 1.5 to vCloud Director 5.1. One question they have is: “Do we have to migrate to vSphere 5.1 at the same time”? The answer is definite no. vCloud Director 5.1 supports vCenter 5.0 and ESXi 5.0 and even ESX(i) 4.0U2 if managed by vCenter 5.

I always recommend to upgrade vCloud Director in two phases.

Phase 1 (vCloud Director Upgrade)

  • vCloud Director Cell operating system (RHEL). RHEL 5 is still supported but if customer wants to use RHEL 6 he will need to deploy a new cell as RHEL 5 to RHEL 6 upgrade is not possible.
  • vCloud Director runtime upgrade
  • vCloud Director database schema upgrade
  • vShield Manager upgrade
  • vShield Edges upgrade

Phase 2 (vSphere Upgrade)

  • Installation of SSO
  • Installation of Inventory Service
  • Installation/upgrade of Web Client
  • vCenter Server upgrade
  • ESX hosts upgrade
  • distributed virtual switches upgrade

As the phases can be spread out in time this brings the main topic of the article – which new vCloud Director 5.1 features depend on vSphere 5.1 and will not be available during the time between Phase 1 and Phase 2? I have compiled a table which lists the new vCloud Director features and if that feature will be available with vSphere 5.0 (vCenter 5.0 + ESX 5.0. Note: I don’t dare to consider ESX 4).


vSphere 5.0

VM Snapshots

Storage Profiles

Elastic VDC

Allocation pool Org VDC type can span multiple clusters. Online migrations and merging of Provider VDCs.
Provider Single Sign On vCenter SSO required
Customer Single Sign On

VXLAN Networks vSphere 5.1 vmkernel module is required
Storage clusters (SDRS)

VM placement engine leverages SDRS. Migration of linked clones supported. Difference in shadow VM handling¹
New Edge Gateway Features

Performance, HA, Load balancing, DNS relay, Rate limits, Multiple interfaces, IP allocations, SNAT and DNAT rules
Virtual Hardware 9 Requires vSphere 5.1 (64 vCPUs)
Additional Guest OS Support


Depends on ESX version (Windows 8/2012 requires ESXi 5.0 U1), but Virtual Hardware 9 is recommended (KB 2034491)
NFS VAAI Fast Provisioning Requires vSphere 5.1 (hardware accelerated linked clones)
Clustered database support

¹) With vSphere 5.0 vCloud Director does not use SDRS recommendation for linked clone placement (Fast Provisioning). vCloud Director picks individual datastore and optionally deploys shadow VM. With vSphere 5.1 vCloud Director fully leverages SDRS recommendations, shadow VMs are deployed by vSphere SDRS.

Table in PNG format.

Disclaimer: I don’t claim this table is complete and that it is an official VMware document. If you think something is missing, please comment and I will edit the table.

Edit 27 April 2013: Explained difference in linked clone placement.