[CentOS] not using LVM for Linux VM guests?

[Paul Griffith]

On 11/17/2011 11:13 AM, Jon Detert wrote:
> Hello,
>
> ----- Original Message -----
>> From: "Russell Smithies"<Russell.Smithies at agresearch.co.nz>
>> To: "CentOS mailing list"<centos at centos.org>
>> Sent: Wednesday, November 16, 2011 2:37:54 PM
>> Subject: [CentOS] not using LVM for Linux VM guests?
>>
>> I came across an old post comment yesterday (from
>> http://echenh.blogspot.com/2010/04/how-to-extend-lvm-on-vmware-guest-os.html
>> ) discussing the "hack" of LVM on Linux VM guests and whether it's
>> better not to use it to simplify disk management.
>> I've re-posted the comment below, does it sound reasonable? Is it
>> better to not use LVM on Linux VM guests?
>>
>> --Russell
>
> I've had the same question.  I've decided to continue to use LVM, for these 2 reasons:
>
> 1) my hypervisor, good, bad or indifferent, is VMware ESX 4.x and ESXi 4.x.  Those hypervisors can't create virtual disks greater than 256 GB.  So, if I want a file-system larger than 256 GB, I have to have some other software - LVM, in this case.

Just to clarify one thing with large virtual disks. The size limitation 
is determined by the block size.

To create a file bigger than 256GB, the VMFS filesystem needs to have a 
block size larger than 1MB. These are the maximums:

VMFS-3 (ESX/ESXi 4.x)

Block Size Maximum File Size
1 MB - 256 GB (default)
2 MB - 512 GB
4 MB - 1 TB
8 MB - 2 TB

http://kb.vmware.com/kb/1003565

With VMFS-5 has a maximum virtual disk size of 2TB minus 512B, with a 1 
MB block size.

Cheers,
Paul