vmware esxi 5 configuration tests

8/12/2019 Vmware ESXi 5 Configuration Tests

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Vmware ESXi 5 Configuration Tests

Background:

These tests are conducted to judge the feasibility to migrate & upgrade the current virtualization

infrastructure from Vmware server 2 to ESXi 5. Currently we have 2 host servers (SUSE SLES 11 with

Vmware Server2), running 5 VMs (Kerio Firewall, ADC, DHCP, Aspire, Linux Update Server ) and the

setup is running quite well for almost 10 months.

The problem with this setup is that in case of any disaster (for example dead server or HDD) the failover

procedure is not very smooth and elegant. What we usually do is copy the VMs from our primary server

to backup server , then attach/map LAN cards to proper VMs via web console and run the VMs. Though

it seems quite easy, in reality it has some severe drawbacks. These include:

1) The host servers are running in Active/Passive mode meaning when the Primary server isrunning, the Backup server remains shutdown and during the disaster we power up Backup and

shutdown Primary. The complete procedure is manual.

2) VMs doesnt sync among both servers automatically. We have to manually track and update theVMs to Backup server after sometime (mostly by-weekly) so that both severs remain in sync and

contains the updated copy of all VMs. This takes long time as the combined size of all VMs is

around 50GB60GB.

3) Mapping of LAN cards in both servers is different thereby causing confusion when connectingLAN cables into server.

4) Performance of VMs can be slower since the Vmware software is running on top of existing OSwhich causes overhead. Though we havent seen such problem in our environment (180+ users)

but it makes sense to eliminate the host OS completely.

5) Sometimes an outdated copy of the VM can be run if it doesnt cause problem. For example, wehave SUSE DHCP and Kerio firewall whom we doesnt update often and during a problem we

runs an outdated copy of these VMs. But never ever try to run an older version of AD/ADC VM

because if the USN number of DC/ADC mismatches then itll stop replicating information and

becomes a non-functional. Itll also cause inconsistency in Active Directory database and creates

problem which are very difficult to diagnose and troubleshoot. We learned it the hard-way.

Even after having the above problems we dont have any stability or performance issues from using

Vmware Server 2 and it can be confidently used as a test bed before migrating completely towardsvirtualization.

Evolution:

As the next logical step well migrate our virtualization infrastructure to ESXi 5 hypervisor. But before

continuing we want to be sure that it is beneficial to use in our environment in terms of fault-tolerance,

high availability, better manageability and foremost, the cost (hardware).


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We have planned a series of tests during July 2012 to check different configurations of ESXi 5, check

failover options & timing, check high availability and finally check fault-tolerance.

Configuration 1

Tests conducted on: July 1, 2012Tests conducted by: RSK

Tests conducted at: PEvo Headoffice

Total time spent: Almost 8 hours

Software used: Vmware (vsphere) ESXi 5, Vmware VSphere Client, FreeNAS

Scenario:

Reason to Test this Configuration:

To see if we can use software based NAS connected via 100Mpbs LAN link (It is required for failover and

HA).

Explanation:

ESXi 5 host PC is connected to FreeNAS software storage server via 100Mbps LAN. FreeNAS would

become an iSCSI Target and VM datastore.

I wanted to test that what would be the level of performance if I move the VM datastore from ESX host

server to a storage server? Since we dont have any dedicated hardware NAS weve built one using

FreeNAS software.

After configuring iSCSI on FreeNAS we make it available to ESXi, and create 2 VMs in it. Windows Server

2003 & SUSE SLES 11 is installed as a test. The average performance during installation was very good

and it doesnt seem in a least bit that the storage system is separate from ESXi host itself. Read/Write

access speed was very good, following figures shows the different stats.

ESXi 5

HostServer

FreeNASStorage Server

Core2Duo 2.8Ghz

7GB RAM

80GB HDD

6 Gigabit LAN

Core2Duo Xeon

2.8Ghz

1GB RAM

250GB HDD

Connected via 100Mbps LAN


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FreeNAS Stats (During both OS installation)


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SUSE SLES 11 Stats

Average traffic transfer during installation from ESXi host to NAS server (1min stats)


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Windows Server 2003 Stats

Average traffic transfer during installation from ESXi host to NAS server (1min stats)


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The Crash Tests:

A series of crash tests have been performed after the installation of VMs to check the stability of

external storage and ESXi since there is a risk of single point of failure as everything is connected via a

simple CAT6 cable. The tests finding are listed below.

Crash Test 1Crash Performed:

Disconnect LAN connectivity for 5mins between ESXi server & NAS server while the VMs arepowered on.

During Crash:

Vsphere client hangs VMs OS services remain offline (no ping, no mstsc etc.)After Recovering from Crash

VMs come online and didnt power off or restart. No damage to VMs. Crash Test 2

Crash Performed:

Restart ESXi host normally. NAS remains ON.During Crash:

VMs OS services remain offline (no ping, no mstsc etc.)After Recovering from Crash

It was observed that some VM doesnt powered off gracefully. It happens due to 2 reasons.First, if Vmware Tools isnt installed inside VM and secondly if ESXi

Configuration->Startup/Shutdown settings isnt set to Guest Shutdown (Default is Power

off).

Crash Test 3Crash Performed:

Set ESXi to autostart VM upon boot and check if it happens or not.During Crash:

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After Recovering from Crash

All VMs started successfully. Crash Test 4

Crash Performed:

Start/Power ON ESXi host with VM set to auto start. NAS is disconnected/powered OFF.During Crash:

ESXi boots up extremely slow since it tries to connect to NAS during boot up.After Recovering from Crash

All VMs started successfully.

vmware esxi 5 configuration tests

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