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From: "Jorge Fábregas" <jorge.fabregas@gmail.com>
To: linux-lvm@redhat.com
Subject: Re: [linux-lvm] Extend VG - Expand LUN vs New Disk
Date: Mon, 21 Dec 2015 12:13:35 -0400	[thread overview]
Message-ID: <5678252F.2040304@gmail.com> (raw)
In-Reply-To: <20151221125008.GB16946@hex.gsslab.fab.redhat.com>

On 12/21/2015 08:50 AM, Bryn M. Reeves wrote:
> Expanding an existing LUN may involve resizing partitions - that is
> normally the step that makes this the more complicated route since
> depending on system configuration and use it may not be easy to resize
> the partition without downtime (the Linux kernel has for some time
> enforced restrictions on resizing in-use partitions - device-mapper
> devices and whole disk devices do not share this limitation).

We use whole disks all the time :)

> It's safe enough - it's just that the kernel generally won't let you
> do it while the existing partition is active and in use.

I'm glad to know that:  one more reason to use whole disks.  I know Red
Hat favors partitions for PVs (as mentioned in various docs) but I've
never been convinced by the arguments for it.


> Expanding an existing partition may be seen as the "cleaner" option,
> since it avoids creating additional PVs and associated labels and
> metadata areas, but unless you are working with very large numbers of
> devices it makes little difference to most operations.

Excellent point.

> Gluing lots of devices together is one of the main reasons for using a
> volume manager and for typical uses it adds no appreciable overhead
> or additional complexity.

Thanks Bryn for your wonderful feedback.  I appreciate it!

All the best,
Jorge

      reply	other threads:[~2015-12-21 16:15 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-21 12:30 [linux-lvm] Extend VG - Expand LUN vs New Disk Jorge Fábregas
2015-12-21 12:50 ` Bryn M. Reeves
2015-12-21 16:13   ` Jorge Fábregas [this message]

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