[lug] Using Loopback for /boot?

Wed Oct 23 13:41:30 MDT 2013

Unless I have a strong reason not to, I do all my Linux installs on single
partitions. Strong reasons include:

- Multi-boot machine with another distro/os
- Using LVM and /or encryption (or some other FS tech) that requires
multiple partitions to behave correctly
- Hardware constraints on available storage devices.

I agree with the sentiment that the "many-partitions" approach is a
hold-over from the days where it would be reasonable to assume that a
single system image would need to span many independent disks that might be
filled and/or upgraded individually over time. That's just not the case
anymore. Even on large high performance servers the split is rarely more
complex than "system/data".

Since we're talking about partitions, One thing that is a good practice
that many people don't think of is if you are using large partitions with
the EXT* filesystems is to make sure you reduce the amount reserved for
root. On a 1TB disk, the default settings would set aside 50GB, which is
just silly.

On Wed, Oct 23, 2013 at 1:23 PM, Davide Del Vento <
davide.del.vento at gmail.com> wrote:

> I don't have the answers to your "pressing" questions, but here are my
> "gut feelings":
>
> 1) I doubt loopback would work in the early stage of the boot (e.g.
> encryption doesn't)
> 2) I believe using your existing boot put you at higher risk of causing
> problems than the solutions you believe are more risky (i.e. creating a new
> partition or using a single partition)
> 3) deleting one partition and creating two (or more) new ones in that
> space is a piece of cake and has never failed for me (out of maybe 50 or so
> times I've done it since the late 90s). That does not mean it will not fail
> on you, of course. And of course you have to pick the RIGHT partition to
> delete, if you pick the WRONG one, all your data is gone (but that's true
> even without the re-partitioning, since you will format it)
>
> Regarding your other question "how many people here no longer use a
> separate /boot?" I guess you have to specify "for what purpose".
> In the last 5 years I've not used separate /boot partitions for my laptops
> and desktops (about 6 machines, about 3-4 installs on each, the first on
> each after wiping out windows, the other doing something similar to what
> you are doing now). I've never experienced any problem with my approach. In
> this timeframe I've not done any server install.
>
> Finally, the link I gave does not simply claim your quote. It's a
> discussion among people and one person claims that. Other people claim
> different things. I claim that a /boot partition is unnecessary, in my
> experience for my use case (which is for a home/office use).
>
> Cheers,
> Davide
>
>
> On Wed, Oct 23, 2013 at 12:56 PM, <stimits at comcast.net> wrote:
>
>> Actually, I forgot to add one option, as per the thread title...I was
>> also considering if I could create a loopback mounted file from the
>> existing /boot. E.G., create a file and format it under loopback, then use
>> that during the install...the file would be on the original /boot, and act
>> something like a jail to prevent interacting with other files. Not sure if
>> during install there would be that kind of ability to name a loopback file
>> as a /boot install, although I could create the file before install.
>>
>> As for a new separate partition, all current partitions are what I have.
>> I do not use lvm, and repartitioning a partition in the middle of the
>> others without touching those surrounding it is a possibility, but this too
>> worries me. Simply making a new partition if there were space at the end of
>> the drive would not be an issue, and due to losing data before manipulating
>> a partition in the middle worries me when I can't afford to lose anything.
>>
>> But...making an install to a new subdirectory of the existing /boot seems
>> to be perfect. However, I'm wondering if this is compatible with chain
>> loading...it's been years since I messed with such boot details, but I am
>> thinking there may be requirements of where files are placed in /boot
>> relative to PBR. The motherboard is about 4 years old, so I'm assuming this
>> is not likely an issue.
>>
>> I should state that my real question is "what are the safe ways of using
>> the existing /boot *partition* and grub2 to not risk the existing linux
>> install and existing windows 7 install". I'm very weary of any downtime, or
>> any install method which could prove risky to any data. What are the risks
>> of manipulating a non-lvm unused partition in the middle of the disk? What
>> are the risks of installing a second fedora using the exact same /boot?
>>
>> The web link you gave does inspire me to simply install everything on one
>> partition...it claims:
>>    This is a holdover from "ye olde tymes"
>> ...how many people here no longer use a separate /boot? Alternately, if I
>> installed everything to a single root partition, and then eventually
>> satisfied myself that all things are copied over and I was willing to
>> destroy the old f16 and its /boot, how hard is it to migrate from one /boot
>> directory on the root partition to a separate /boot partition (thus
>> overwriting the old f16 /boot)?
>>
>> I guess the ideal situation would be that a separate /boot partition
>> really does no longer have any meaning or advantage.
>>
>>
>> ----- Original Message -----
>> From: Davide Del Vento **
>> To: Boulder (Colorado) Linux Users Group -- General Mailing List **
>> Sent: Wed, 23 Oct 2013 18:30:30 -0000 (UTC)
>> Subject: Re: [lug] Using Loopback for /boot?
>>
>> Why do you want to *share* boot?
>> If I were you in your shoes I'd just make another *separate* boot
>> partition (mounted as /boot in F19 and something like /f19boot in F16) and
>> use that instead. Or even do not make a /boot partition at all, of course
>> this has pros and cons as you probably know
>> http://unix.stackexchange.com/questions/256/is-it-good-to-make-a-separate-partition-for-boot
>>
>>
>>
>>
>> On Wed, Oct 23, 2013 at 12:15 PM,  <stimits at comcast.net> wrote:
>>
>>>
>>>
>>> Hi,
>>>
>>> I have an older machine with hardware issues on SATA ports which means
>>> the two disks I have now are the only disks I can attach. I'm interested in
>>> installing a newer version of fedora 19 (it has an existing fedora 16
>>> install) to a spare 300 GB partition. The trick is that I have only one
>>> /boot, and I do not want to harm the older install until I'm sure
>>> everything is up and running on the newer install. The /boot/grub2/ is what
>>> worries me.
>>>
>>>
>>>
>>> Current layout is no lvm used (just ordinary partitions). Drives: first
>>> SATA drive contains windows 7 and linux swap (sda), while the second hard
>>> drive contains fedora 16 and /boot (sdb). Second drive also contains the
>>> spare 300 GB partition (sdb), currently formatted ext4. My desire is to
>>> install fedora 19 to the spare sdb, share the /boot and swap, and either
>>> edit the existing grub boot from old fedora 16, or replace it with the new
>>> fedora 19 grub boot, with windows 7 and all linux installs remaining
>>> bootable with no down time. FYI, without everything remaining on the
>>> existing drive, I cannot add a new drive without replacing the motherboard.
>>>
>>>
>>>
>>> I suspect I can simply install fedora 19 and tell it to not format
>>> /boot, then tell it to install on MBR of sda, or possibly even tell it to
>>> not even install boot to MBR, but instead edit the grub boot menu. Kernels
>>> themselves would not be overwritten due to version naming, but I still
>>> worry about grub issues. Can anyone give me advice on how dangerous this
>>> scheme is to damaging any of the existing operating systems? Or insights on
>>> using a single /boot for two fedora installs? I'm trying to avoid putting
>>> /boot on the same partition as / for the new install, but perhaps this
>>> would be the only way.
>>>
>>>
>>>
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>>
>>
>>
>> ****
>>
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>
>
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