What's the actual deal with VMWare / ESXi ?

[SayKyo]

Hello everyone,

I have access to a fairly simple new VMWare cluster, which consits of a pair of DL360Gen8 HP worker servers connected to a P2000 G3 MSA SAS storage array having RAID6 and RAID10 vdisks. The main point of this setup is to provide hardware and data redundancy to it's users and, as you might have guessed, one thing I wanted to do was to run FreeNAS in a virtual machine. I didn't pay much attention to the forums, so simply downloaded the ISO, set it up, tested that it works the way I wanted to and was happy. You can only imagine my horror when I found all the warnings here on the forums, which all seem to boil down to "if you need to ask about FreeNAS in a virtual environment, don't try". After having read the following threads:
- http://doc.freenas.org/index.php/FreeNAS®_in_a_Virtual_Environment
- http://forums.freenas.org/index.php...ide-to-not-completely-losing-your-data.12714/
- http://forums.freenas.org/index.php...nas-in-production-as-a-virtual-machine.12484/
- http://forums.freenas.org/index.php?threads/vmware-tools-and-freenas-8.10160/
and some other discussions here on the forums, I am a bit confused as to the reason why this is actually so, so if anyone could provide clarification on these issues, I'd be glad. Just to point out where I'm getting at, I have zero experience with ZFS and I don't care about performance that much, I just need to make sure the data is safe.

First of all, there's talk of PCI-Passtrough as a must, which I quite don't get. My virtual disks are working just fine in linux and windows hosts, so why can't/shouldn't ZFS use virtual disks? Is there something different about it using the virtual controller? And what does the passtrough feature has to do with anything?

Secondly, there was a talk about problems with strating disks in the right order the moment the VM is started. What's the deal here? My virtual disks located on the array are all immediately avaliable the moment the VM starts and if not, that must mean the whole array is dead as well, so am I missing something ? Am I guessing correctly that this might be an issue only for people storing their VM's on remote iSCSI/NFS storage pools, which is not my case (and hence, not my problem) ?

Third of all, there's talk of lower VMWare performance, or the need to explicitly reserve resources for FreeNAS in order for it to run correctly. As far as I'm concerned, performance is not an issue, I just need to make sure the data is safe and sound. Would could case data loss or data corruption in the setup I'm using?

Thank you to everyone who shines some light on this for me!

 

[term]

The first post in the third thread you linked answers all your questions. It explains why ZFS does not prefer virtual disks. You'll need to allocate at least 8GB of ram for freenas to function correctly, and more depending on the size of your disks/pool.

I know some people are running it successfully, but they have enough knowledge and backups and are willing to accept the risks. At least you are trying to educate yourself before you lose data. It seems like a lot don't.

 

[ser_rhaegar]

1. Why use freenas if it cannot monitor the hardware for failures? The passthrough is needed to monitor S.M.A.R.T. on the drives.
2. Many people use the FreeNAS VM as iSCSI/NFS storage for VMWare. So you need VMWare to boot, start FreeNAS, wait for the drives to be available then it can find and load the other VMs it is hosting that use FreeNAS as the storage for the virtual disks.
3. FreeNAS needs the resources not only for performance but for reliability.

All the links you posted explain each item here in better detail. If you're not understanding the content from the links, I would avoid using FreeNAS as a VM as you're risking your data at that point.

 

[jgreco]

I will expand upon one point, the rest of what I would have to say is ALREADY said in link #3 above.

If you have virtual disk*S*, plural, and VMware manages to lose one of them, probably because you did something stupid like creating a bunch of virtual disks on top of a bunch of nonredundant physical disks, and then had one fail, is that actually a failure mode you've tried, and you know how the hypervisor will react?

No?

Didn't think so.

So let me be exceedingly clear here: There are very good reasons that I wrote two of your four listed documents, and my reasons all involve my wanting to protect your data.

People have lost data, and/or had unexpected problems in recovering data, from such setups.

Some of us run FreeNAS virtualized with no problems. Making it look easy is not the same as actually being easy.

When Steve Jobs introduced the original iPhone, he made it look so easy and wonderful on stage. But the reality is that Apple had devised a golden path for him, a set of actions he could take during the demo to minimize the risk of crash and embarrassment. Running FreeNAS on VMware is quite a bit like that. You are welcome to walk off the golden path and have your own adventure. I will wish you well and cross my fingers you don't lose your data.

But that's what may lie ahead for you. For anyone smart enough to read the documents I wrote and say "oh yeah that makes complete sense," they're probably sufficiently proficient to step off the golden path I've devised and explore the boundaries. I have no interest in doing so; I merely need storage that I can rely on. Being able to recover data if the hypervisor goes insane is important. I value being able to plug in a USB key and boot and do a "zpool import".

But no one forces you to follow our advice.

 

[cyberjock]

And i'm locking this thread. There's no reason to hash this out again and again. We've written the stickies. Use them.

 

[jgreco]

I've expanded a bit upon at least one of the stickies.