[linux-lvm] LVM newbie question.

[bscott at ntisys.com]

On Tue, 23 Jul 2002, at 4:49pm, Melinda Taylor wrote:
> When I do a pvcreate on say /dev/sda1 does that destroy all the existing
> data on that partition?

  Yes.

> Is there any advantage over [creating a PV on a partition vs a whole
> disk]?

  Not really.  Do whatever makes the most sense for your situation.

> One part of the how-to said converting a root system to LVM is not
> recommended.  SHould your OS directories /var / /boot etc all not be
> included in the LVM?

  Basically, to keep things simple, it is recommended that the boot and root
partition(s) not be placed on LVM.  This is because many boot/rescue/install
environments do not support LVM, making recovery from a boot failure
difficult to impossible.

  By placing / and /boot outside of LVM, you can repair them from just about
any boot/rescue/install set, and/or boot without LVM working.  Once you're
booted from the HDD in single-user mode, you can use the LVM utilities (in
/sbin) to get the rest of the system (on LVM) working.

> That was the main idea behind me implementing LVM so that specific
> partitions (say var) could be resized at a later date if needed.

  The system will typically boot with / mounted read-only.  Nothing else is
mounted, so if /var or /tmp or /usr or whatever are separate filesystem(s),
that is fine.  The system boot scripts (e.g., rc.sysinit) should start the
LVM and mount any needed filesystems.

> Will I have any trouble restoring my system (which I backed up using dd
> with a BS of 1024k)

  Using "dd" for backups is a bad idea.  Use a backup tool, such as "dump",
"cpio", or GNU "tar".

-- 
Ben Scott <bscott at ntisys.com>
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