Datastore not formatting larger than 2TB

[Mako77]

Hi,

I have a server with ESXi5.1 and a LSI non raid card which connects to a Infortrend RAID DAS. The server and ESXi are seeing the raid and reporting correctly at 3TB. However when I go to 'Add Storage...', and choosing VMFS-5 of course, the formatting page says:

Disk layout: Format: GPT Primary Partitions Capacity 2.72TB

File system:Maximum filesize 2TB

What does it mean by Maximum filesize 2TB ???

Also in the VMware EXSi 5.1 maximum capacities, it states it can only have a 106k files ??? What is this in relations too ??

I'm making a VM file server which I want to use the DAS for the full storage. Is it better to use VMDK or RDM ??

Thanks

Ed

[depping]

It means that the file you create on your VMFS filesystem can be 2TB at most.

[Mako77]

Thanks. So what it means is the VMDK files can only be 2TB and that therefore you can only have 106k VMDK (or other files) on a datastore??

In which case how do people provide disks which need more than 2TB to VM's ???

[schepp]

Mako77 wrote:

In which case how do people provide disks which need more than 2TB to VM's ???

Add multiple VMDKs to a VM and combine them inside the guest OS.

Regards

[RanjnaAggarwal]

Use RDM in Physical Compatibility Mode if you need that in one disk otherwise you can attach multiple Virtual HDD's in one vm.

[Mako77]

Thanks for responding.

So I'm making a VM file server which I want to use the DAS for the full storage. Is it better to use VMDK's or RDM ??

Sorry, haven't done this in ESXi before, only played and run VM's without much storage So learning fast.

Thanks

Ed

[Mako77]

Is it better to use VMDK's or RDM ??

[depping]

Mako77 wrote:

Is it better to use VMDK's or RDM ??

It doesn't really matter. There is hardly any performance difference to be found between the two, I would say VMDKs are easier to manage so that has my preference.

[Mako77]

Thanks.

From a OS point of view, from the reading I'm doing. Would it be better to provide it as one partition or as multiple VMDK and then stiching those together in the OS. The OS being Windows 2012 ?

My understanding is if you had one VMDK go corrupt you loose the whole volume ?

Ed

[Mako77]

Having had a play, I thought one option might be to:

Create a VMDK of 2TB and use that as a basic disk in WIndows 2012.

Then hopefully when the next version of ESXi comes out I can expand the VMDK and also expand it within Windows 2012.

Does anyone see a problem with that idea?

[schepp]

I am running multiple Windows fileserver ( 2008R2 )  with up to 5 x 2TB VMDKs each for 4 years now. Never had any problem.

Why do you only want one VMDK? The problem I see is when the next version of ESXi don't support larger VMDKs, you still got no solution.

[Mako77]

Well I've heard and from prior (long ago experiance) dynamic disks within Windows 2012 can be a pain if they go wrong or get corrupted ???

http://vmtoday.com/2013/04/is-spanning-vmdks-using-windows-dynamic-disks-a-good-idea/

Are you running them as Dynamic Spanned disks ?

[schepp]

Yes I'm running them as dynamic spanned.

The thing with your one, >2 TB VMDK is, everything is lost ad well when that is corrupted. That's why you do backups

[Mako77]

Yes this is true but I would hope not to have to do that

I suppose it becasue of the bad problems I've heard ppl of run into with dynamic disks.

How does it work from the point of view of having to rebuild the server. If I had to rebuild the VM or redirect the disks to a new VM, does Windows pick up the dynamic disks in order correctly if they are all presented correctly ?

I suppose the other question is moving forward that once a dynamic disk which is stripped is made then if ESXi did increase the 2TB limit I wouldn't be able to change to a simplier setup. As where if I start with the 2TB basic I still have the choice when I reach that limit to either go multiple 2TB VMDK or just increase the current 2TB VMDK...??

[Mako77]

Bit of a long question but what sort of speed would you expect to see doing a disk to disk copy within a VM of a Windows.

55MB/s to 80 MB/s

[schepp]

As always... it depends 🙂

It depends on where your VM is located. What kind of datastore. What RAID level is the datastore? How Many disks are in that RAID? What other processes are running on that disks?

I just tested a 3GB file copy from disk to disk to give you some example numbers:

VMDKs on RAID6 with 11 disks. 97 MB/s transfer rate

Regards