Disk layout for XO-1.5

[david at lang.hm]

On Tue, 28 Jul 2009, Mitch Bradley wrote:

> Another important advantage to partitions is that the existence of a boot 
> partition isolates the firmware from changes in the filesystem used for the 
> root.

can you explain this a bit more?

> Advantage #2 that you cite below is also quite valuable - it makes it easy to 
> preserve user data while replacing/recovering/updating the system software 
> using the "blast on a fresh image" method.

only partially true, since sugar wants to install apps in /home, trying to 
reset things requires reimaging /home as well.

David Lang

> david at lang.hm wrote:
>> On Tue, 28 Jul 2009, Chris Ball wrote:
>> 
>>> Hi, [adding fedora-olpc-list to CC]
>>>
>>>   > Are we stuck with 1.1GiB or do we think we can reduce that further?
>>> 
>>> Well, there are a few things going on here.  We have activities and
>>> content (and will probably add more activities and content) that's
>>> currently part of the 1.1GiB, but is actually in /home, and isn't
>>> going to count towards our "system partition" use.  So we need to
>>> split that out in our calculations; currently 162MiB of the 1.14GiB
>>> used is in /home, so we're actually just under 1GiB.
>>> 
>>> It seems likely that we can reduce the system partition size by one
>>> or two hundred MiB without extreme effort, but I haven't looked into
>>> where the space is going yet.  However, after we do that we're going
>>> to want to add more applications, such as OpenOffice, so I wouldn't
>>> want to commit to staying under 1GiB for a single system partition.
>>> (It wouldn't be necessarily *bad* to use more than that, if the
>>> things we're going to add are valuable and we've cut out the cruft
>>> we're not actually using.)
>> 
>> so you are moving away from abiword (which I understand write is a 
>> derivitive of) and adding openoffice??
>> 
>> given the capabilities of these machines, and the bloat of openoffice, I'm 
>> not sure that's a wise move.
>> 
>>> So, let's go ahead with the discussion about whether we want to use
>>> partitions and what they should be called/what filesystems we should
>>> use for them, without committing on a size just yet.  If one of the
>>> fedora-olpc readers could come up with a report listing our installed
>>> RPMs by size on disk, that would rock.
>> 
>> while it is traditional to use seperate partitions, on a 4G flash drive is 
>> it really worth the cost of guessing sizes wrong?
>> 
>> advantages to using partitions
>> 
>> 1. filling up one partition won't affect others (making it easier to run 
>> tools to recover space)
>> 
>> 2. you can wipe one parition in an upgrade without affecting data in other 
>> partitions
>> 
>> 3. it's possible to set different permissions on different paritions 
>> (nodev, etc), which increases security if users only have access to write 
>> on those partitons.
>> 
>> disadvantages to using partitions
>> 
>> primarily boils down to one
>> 
>> you have to decide ahead of time how big to make the partitions, and 
>> changing this later is non-trivial. if you guess wrong you can end up 
>> running out of space in one place while you have extra space in others.
>> 
>> 
>> 
>> In my opinion, there are two reasonable approaches
>> 
>> 1. multiple system paritions so that you can have two completely 
>> independant systems on the box and dual boot between them
>> 
>> 
>> 2. single partition
>> 
>> 
>> since this is only a 4G drive, I would tend to go with #2.
>> 
>> in the current discussion the proposal is to leave 1/4 of the disk space 
>> unallocated, but unavailable to the users 'just in case' it's needed for 
>> the OS later.
>> 
>> the multiple system partition approach has a similar problem, but there it 
>> gets a lot more value for the space.
>> 
>> the fact that it takes ~1G for a minimal desktop system is very 
>> disappointing.
>> 
>> David Lang
>