Re: Can squeeze boot into a LVM over RAID?
On Sat, 01 Sep 2012 17:18:33 -0500, Mark Allums wrote:
> On 9/1/2012 4:58 PM, Mark Allums 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.
>>>>
>>>> Mark
>>>
>>> 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?
>>>
>>> - hendrik
>>>
>>>
>>>
>> 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.
>>
>> Anybody else know?
>>
>> Mark
>>
>>
>>
> I would add that Squeeze probably does not write the MBR to all disks at
> install time if installed using the default automated install, but with
> an expert install (that you are already using since you are installing
> RAID and LVM) you can write the MBR to each disk.
It doesn't matter much what the squeeze installer does. THis system was
installed using at the latest by the lenny installer, and possibly even
the etch installer, and has been upgraded from stable release to stable
release for a very long time.
Everything is very much post-installation1
> After installation, say during the installation of a new kernel or an
> update to GRUB, you will be asked which disks to write the MBR to by the
> installation script, so you're okay there. It's only during the initial
> installation where you might have to manually intervene.
It never asks me during upgrades.
-- hendrik
>
> Under Wheezy, I think the installer has gotten smarter.
>
> Someone please correct me if I am mistaken.
>
> Mark
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