[CentOS] not using LVM for Linux VM guests?

Thu Nov 17 19:25:10 UTC 2011
Smithies, Russell <Russell.Smithies at agresearch.co.nz>

> -----Original Message-----
> From: centos-bounces at centos.org [mailto:centos-bounces at centos.org] On
> Behalf Of Jon Detert
> Sent: Friday, 18 November 2011 5:13 a.m.
> To: CentOS mailing list
> Subject: Re: [CentOS] not using LVM for Linux VM guests?
> 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-o
> > s.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.
> 2) I like being able to give disk devices descriptive names, like
> /dev/mapper/zimbra-data instead of simply '/dev/sdb' or similar.  There are
> probably ways other than LVM to do that, but LVM does offer that flexibility.
> One thing I do avoid, however, is partitioning the virtual disks that might
> need to grow.  This is because of the pain described in part below.  The
> kernel often seems to have a hard time letting go of it's view of the partition
> table - either i have to umount the partition, or reboot.  However, if i use the
> disk unpartitioned, the kernel has no prob, and I can *extend and/or
> resize*fs without umount or reboot.
> - Jon

I have the same problem - I can never get the partition table reread without a reboot.
It's a little annoying as I can resize the disk on a Win2k8 VM without a reboot but not Linux :-(

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