On 11/17/2011 11:13 AM, Jon Detert wrote:
Hello,
----- Original Message -----
From: "Russell Smithies"Russell.Smithies@agresearch.co.nz To: "CentOS mailing list"centos@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:
- 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