Windows Various ESXi questions including running an Active Directory Domain Controller

The free version also only support full backups, not incrementals or anything fancy like that, so you'll need to manually take a full backup.

 

We use Hyper-V for our infrastructure, which is entirely windows based, and it works very well. With regards to your questions,

1. Having only used VMPlayer for personal testing, I wouldn't be able to comment on the performance although there are some limitations on the flavours of linux that Hyper-V supports.

2. In terms of flexibility, Hyper-V (in particular, Hyper-V with Windows Server 2008 R2 SP1) has introduced things such as dynamic RAM allocation, providing quite a bit of flexibility.

3. Hyper-V can support expansion of .VHD although not "hot" expansion. You can add "hot" SCSI HDDs although these cannot be boot or system drives. Other "hot" expansion of devices is not supported however.

4. Yes

There are some other features (which ESXi may support) that really are quite good, particularly when it comes to HA (High Availability). Hyper-V, including the free stand-alone, fully supports Microsoft's failover clustering. Hyper-V also has CSV (Cluster Shared Volumes) which enables live migration of VMs with no disruption to service.

AFAIK, the only licencing issues with Hyper-V are how many VMs you're allowed without additional licences. Windows Standard supports no addition VMs meaning you would have to buy an additional licence per VM, Enterprise supports 4 VMs meaning you would have to buy an additional licence for your fifth server and Data Centre supports unlimited VMs.

 

So ESXi can expand virtual drives? Is this feature reserved for the paid versions or is it in the free one also? Can it also shrink virtual drives?

It would be really embarrassing for Microsoft if it didn't, wouldn't it?

As I understand the Windows Server Standard 2012 license, you can run a maximum of 2 virtualized instances with one license, right? And there's no limitation on hypervisor used, so one license and 2 instances through ESXi is possible?

 

And it looks like Veeam costs more than the entry vSphere package! Ouch!
Is it that good?

 

This would be very true...

I'm unsure of Server 2012 but in 2008, I believe the licencing options only apply to if you're deploying Windows server. For example, you could buy Windows standard and you could install 100 VMs if you purchased a 100 new standard licences or installed a 100 non-windows server products. It really just depends on how many Windows Server machines you want as opposed to how many servers.

There isn't a limit to how many VMs actually run on Hyper-V (in terms of licencing).

 

Veeam can do a lot of nice stuff like host-to-host replication, incremental backups, optimised and deduplicated backups, even file-based backups from within a VMDK disk, so I would go with "yes it's totally worth it" - the caveat is that the paid Veeam doesn't work with free VMware (the advanced features of Veeam require vSphere API access, which is locked to read-only on free vSphere), so you either need to go all-free or all-paid I'm afraid.

Another word of advice on the vSphere licencing - you can upgrade from free to paid licensing very easily (the actual product is the same, you're just using a feature-limited version) so if you like you can install two standalone free vSphere hosts and get the setup you want - then if you decide to upgrade them to Essentials so that you can use vCenter and vMotion etc, you just need to purchase the licenses and install the keys.

I must admit I'm still extremely unconvinced on HyperV. According to this link you should reserve 2GB of memory for HyperV itself (and the host Windows OS). This is insane - 2GB for a hypervisor??

The sheer fact that Microsoft has a list of 'supported' Linux distros (which is just SLES, RHEL and CentOS) is reason enough to keep well away for me. Also, according to the HyperV Wikipedia article, any unsupported Linux OS is restricted to 1 vCPU, which is just ludicrous.

 

CSV is actually a part of Windows Clustering, not Hyper-V necessarily, and LiveMigration is the bit that does live migration

In fairness to the above, the same licensing constraints apply to VMware. Typically one would license an ESX/ESXi host with datacentre edition when you know you've got more than four Windows VMs. Non-Windows VMs need licensing appropriately with their vendors, but the Hyper-V host won't care as long as its not Windows. It'll just create virtuals til you run out of cpu/ram/hdd.

Of course, if you were to use ESXi (free) and only run Linux, that would also be free Hyper-V you have to have a Windows license for the host and for each guest, unless you have datacentre edition which goes on the host effectively, with the guests being covered.

FWIW I've built service provider datacentres personally on both VMware and Hyper-V, in fact I'm in the finishing stages of a Hyper-V datacentre now.

- VMware requires significantly less physical ports using their vSwitch technology than Hyper-V - meaning lower switch density, and therefore considerably lower cost as you scale - when deployed in a service provider environment.

- When you need to trunk multiple VLANs into Hyper-V, especially if you are using NPAR to split up 10Gb links, the networking is incredibly fiddly and detailed to configure. Its hard to script it right and predictably. Takes a lot of careful thought. With VMware, you just connect two ports, LACP or Etherchannel them together, trunk some VLANs, and then in VMware create a port group for each VLAN. So frigging simple in comparison.

- The HA is much simpler in VMware but you can potentially pay more for it depending on the features you need due to the tiered licensing. With Hyper-V once you have Windows you can either cluster for HA, or not. Its already included.

For a single-customer environment, there's not a lot of practical difference except you've gotta potentially pay for an extra Windows license for the host. When you start scaling out, well, you've gotta consider more factors!!!

 

That 2 GB is not to run the Hypervisor. It's to run the "parent partition" which is the server 2008 install that manages the hypervisor. The actual Hyper V hypervisor only needs 300 MB to run.

The parent partition is kinda like the service console in the old traditional ESX. Unfortunately the Hyper V parent partition is Windows so is greedy. The ESX service console was linux which can run much leaner than Windows.

Hyper V is alright for small implementations. No good if your going for high consolidation ratios though. I've achieved 50:1 here running vSphere 5 Enterprise Plus on 10 Cisco UCS B200-M3 blades with 196 GB RAM and dual Xeon E5-2680 CPU's.

 

According to the install documentation for ESXi, it requires a minimum of 2GB and upto 8GB for all the features:

Link: http://pubs.vmware.com/vsphere-51/index.jsp?topic=%2Fcom.vmware.vsphere.install.doc%2FGUID-7C9A1E23-7FCD-4295-9CB1-C932F2423C63.html

I think that it depends on your infrastructure, if you're running a predominately windows-based, Hyper-V is an efficient and cost-effective platform. If you're running a mixed environment, VMWare is probably a better solution.

 

Kind of true, CSV is part of Windows Clustering but can only be used with Hyper-V and virtual machines.

My experience is only within a smaller network (15 or so servers) so couldn't comment on large implementations.

 

OK, let's focus on ESXi and talk about specific issues. Here's one:

Have you run in a production environment ESXi hosts without local storage? I know it's possible, but what problems could appear? For one, I guess that memory overcommitting is out of the question since there's no scratch partition.

 

Generally, as most server iron vendors want to sell you a hard drive, you'd just get a local pair of 72gb or 146gb SAS drives and put them in a mirror. As you say, you CAN do it but in all our production environments using iSCSI, we just have a pair of local disks for the local stuff.

 

All my blades are diskless. The VM storage is on a SAN. The blades themselves boot from SAN. memory overcommitment works without any problems as the VMKernel swapfiles for each VM are again on the SAN. The logs from the hosts are stored the SAN also.

swapping VM RAM out to disk is the last thing it will do to overcommit RAM. really you never want to see it happening. The other 3 RAM overcommitment methods it uses before VMKernel swapping are:

1. Transparent page sharing. Identical memory pages from multiple VM's are only stored once in the hosts RAM.

2. Balloning (Idle RAM tax). If RAM starts to run out it will cause the ballon driver installed with VMWare tools within the guest to request RAM. This is then handed back to ESX to give to other VM's.

3. RAM compression. The contents of RAM is compressed.

 

Thanks guys for your inputs. +rep

What would you say local storage could be useful for, except a scratch partition?

 

Booting ESXi & maybe sticking a few ISO's on

 

Booting from a USB stick seems far simpler, cheaper and power efficient. As for the ISOs, I guess I'll have to make do without them. I was thinking there might be some other not immediately evident benefits.

 

USB is slow and not reliable enough for production use.
I always stick a pair of small 14k sas drives in for esxi to use then link via fibre to the San for my datastores

 

I understand that it will boot slower from a USB stick, but should I expect it to fail after some time? If so, I should be safe if I made a clone on an identic stick, right?

 

DO you really want to be plugging your ESXi boot drive in to Windows or Linux to clone it after every update?

Just put a pair of HDD's in or boot from a LUN

 

About the free Veeam, can it backup a VM while it's running, or is that available only in the paid for version?