Ubuntu Preseed Raid 1 with multiple partitions

[Liam Proven]

On 3 June 2013 23:22, Tom H <tomh0665 at gmail.com> wrote:
> On Mon, Jun 3, 2013 at 4:48 PM, Liam Proven <lproven at gmail.com> wrote:
>> On 3 June 2013 21:28, Camilo Vieira <camilo.vieira at gmail.com> wrote:
>
>
>>> I intend to create the following RAID 1:
>>>
>>>     Partition    Size         Filesystem
>>>         /        20GB            ext4
>>>         /boot    500MB           ext4
>>>         swap     2GB             swap
>>>         /backup  10GB            ext4
>>>         /opt     all free size   ext4
>
>
>> Why such a complex layout?
>
> Why not? Although a separate "/opt" on Linux is weird.

Agreed.

> (I'll assume
> that "/backup" and its size make sense.)

Fair enough.

>> E.g. why mirror swap? Indeed on a well-specced machine why use swap at all?
>
> Why not mirror swap? If for no other reason than ease of partitioning.

Performance degradation? Wasted CPU cycles and disk I/O?

> You could also use both sides of the mirror as two swap partitions.

That is indeed what I used to do, when I was running servers with
512MB - 1GB of RAM. (Actually even with a gig of RAM, I'm not sure
it's needed any more.)

> If you don't want to use swap, you have to over-provision RAM; and
> disks are cheaper than memory...

A cheap entry-level PC comes with 8GB these days. 4GB is end-of-line
clearance kit. 3GB was common around 2007-2008 or so.

>> For servers, I use a mirror pair for / and a RAID5 for /home and
>> that's it. No need to split out /boot, /var, /opt and all that any
>> more, not when a terabyte costs the same as a good meal.
>>
>> I keep /home separate. I give about 16-32GB to / and the rest to
>> /home. Job done.
>
> Splitting out "/var" is good practice on a server.

It is, yes, but as I said, I question the need on a modern box. If you
have a problem and you don't notice until you have a terabyte of log
files filling your root FS, your problem is most definitely not your
disk partitioning scheme.

I'd also add that if one were /serious/ about managing large amounts
of space across multiple volumes, one probably ought to be managing
the space via LVM or ZFS rather than raw software RAID.

--
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