Re: Can squeeze boot into a LVM over RAID?
On Sat, Sep 1, 2012 at 5:58 PM, Mark Allums <mark@allums.com> wrote:
> On 9/1/2012 4:46 PM, Hendrik Boom wrote:
>> On Sat, 01 Sep 2012 16:02:54 -0500, Mark Allums wrote:
>>> On 9/1/2012 3:17 PM, Hendrik Boom wrote:
>>>>
>>>> Can squeeze boot when / is on an LVM over RAID1?
>>>>
>>>> Can it boot if /boot is on the LVM over RAID1?
>>>>
>>>> Or when /boot is on a nonRAID nonLVM partition but / is on an LVM over
>>>> RAID?
>>>>
>>>> Context: I have to remove the hard drive my / is on. The available
>>>> space to move it to is on a RAID drive.
>>>>
>>>> The disks carrying the RAID also have small nonRAID nonLVM partitions
>>>> that would be big enough for /boot, but not all of /
>>>>
>>>> -- hendrik
>>>
>>>
>>>
>>> The usual practice is to put everything except /boot on LVM. /boot can
>>> theoretically go on LVM too, but it's simpler to leave it out/off of
>>> LVM. /boot can go on RAID, easily, though, and I always put it on a
>>> RAID 1 partition.
>>>
>>> So, yes, squeeze can boot with / on LVM, whether over RAID or otherwise.
>>
>> Thanks. Will try it in the next few days. Will also install grub to the
>> MBR of all my disks, so whichever gets picked at boot time will work.
>>
>> Is there an eaasy way to do this, so that they'll all get updated as
>> necessary when aptitude installs a new kernel? Or it this not something
>> that the MBR cares about?
>>
>> And is th association of, say, /dev/sdb with a particular hard drive
>> consistent if there's no change in hardware, or does it depend on random
>> boot-tine timing issues?
>
> As Tom H mentioned, on standard Squeeze, not partitioned RAID. Sorry for
> the confusion.
>
> You should use UUIDs or labels if you wand to reliably always boot or mount
> a particular partition. The /dev/sdx designations are subject to the winds
> of variability in a system, and it apparently has been deemed unnecessary to
> sort this out, since UUIDs and labels are available.
>
> Some distributions are smart enough to write the MBR to all disks in a RAID
> 1, and others are not. I don't recall if Squeeze will or won't, or or if
> Wheezy will, for that matter. I haven't installed either recently enough to
> need to find out.
I haven't done a raid install in a while because I've been preseeding
them. But, by default, Debian's d-i (as opposed to Ubuntu's d-i)
doesn't install to to both mirrors of a raid1 array. I remember that
you can ask it to install to both mirrors but it's convoluted. IIRC,
you have to refuse to install grub to the MBR and you then get a
choice of disks and partitions to install to.
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