Re: Attempt to Move Root
On Fri, 25 Dec 2015 10:33:56 -0500 (EST), Stephen Powell wrote:
> On Tue, 22 Dec 2015 10:57:41 -0500 (EST), Nicolas George wrote:
>> ...
>> I noticed that LILO seems to be actually capable
>> of finding the sectors for files on LVM.
>
> In the general case, the sectors of a file on an LVM2 logical volume may
> reside on multiple physical partitions on multiple physical disks. But if
> all of those disks are addressable via the BIOS, and all of the sectors
> are accessible via the BIOS, then it may be theoretically possible for LILO
> to read the map file, the kernel image file, and the initial RAM file system
> image file from an LVM2 logical volume at boot time. I guess I was making
> an implicit assumption that they would all have to be on the same physical
> device. But maybe that's not true. I'll have to look into that.
Looking at the source package for lilo, in src/geometry.c, I find the following:
if (lbm.lv_dev != geo->base_dev)
die("LVM boot LV cannot be on multiple PVs\n");
Therefore, it appears from a cursory examination that an LVM2 logical volume
may be used for /boot if the logical volume maps to a single
physical volume. It is not clear to me from this cursory examination whether
this "physical volume" actually means a partition; or if it means a physical disk,
which may consist of multiple partitions. In any case, I would not recommend
putting /boot on an LVM2 logical volume. It's just one more layer of
complexity, and one more potential thing to go wrong.
--
.''`. Stephen Powell <zlinuxman@wowway.com>
: :' :
`. `'`
`-
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