Re: [gentoo-user] Re: separate / and /usr to require initramfs 2013-11-01

[Gregory Shearman <zekeyg@gmail.com>]

In linux.gentoo.user, James wrote:
> Gregory Shearman <zekeyg <at> gmail.com> writes:
>
>
>> b) The important reason I need an initramfs is that I have my root
>> filesystems on LVM partitions (except for my ARM servers). 
>
> Hello Gregory,
>
> Please tell me, as much as you are confortable  with, 
> about your ARM servers....

I'm running 2 servers at the moment. They are very low power and they
mainly serve my home network. One is a Marvell Sheevaplug (single core
1.2GHZ 512MB memory) and has been running reliably for many years. The
other is a Texas Instruments Pandaboard (2 core Cortex A9 Processor -
1Gb memory) .  I've only had the Panda since October last year and it is
also a very reliable server (with added GUI HDMI benefits!).

> Running Gentoo?  Running Embedded Gentoo?  Which kernels? 
> HDD ? File Systems? Configurations, Grub 2? LVM, RAID ?

Both servers are running Gentoo Stable... therefore current kernels (for
their architecture). Both have external HDD attached via USB.

File systems: root filesystem is on an SDHC card (2nd partition). Other
filesystems (except for the boot partition) are all on LVM. I have
/usr/src, /usr/portage, /usr/portage/distfiles is a symlink to
/var/www/localhost/gentoo/distfiles (another filesystem). I also have
/var/tmp/portage on a separate filesystem and I also run a postgresql
database server which also has its own partition on
/var/lib/postgresql/<version>. Both servers have the same setup as I'm
currently in the process of replacing the sheevaplug with the panda.

Grub? There's no such thing on ARM machines. The kernel or uImage looks
for the first partition on the configured root device (SDHC on my
systems) the first partition MUST be VFAT (unfortunately) and it
contains the u-boot bootloader and the kernel (uImage). Kernels are
built the same way as x86 kernels except you do "make uImage" instead of
"make bzImage".

LVM? All the above filesystems, except the root partition and the boot
partition are LVM volumes. Filesystems are mostly Ext4 (very
conventional).

RAID? Nope.

> Typical usage?

Print server, database server, backups, webserver - which includes serving gentoo
portage and distfiles to other machines on the network (THTTPD is a
great minimal web server).

> What install docs did you follow?

Sheevaplug:

http://dev.gentoo.org/~armin76/arm/sheevaplug/install.xml#install

Pandaboard:

http://dev.gentoo.org/~armin76/arm/pandaboard/install.xml

It's easy.

> Any suggestions on setting up ARM servers, cluster,
> and such are most welcome.

ARM servers aren't much different to other servers but you must realise
that these are low powered devices (the ones I run anyway) and aren't
really suited to large loads. They especially suit a small business or
home hobbyist environment. Even so, compiling Gentoo, especially on the
Panda is not a problem and doesn't take forever (except for gcc
updates 8-)).

I suppose you could cluster a number of these devices but I think it
would be more efficient to use a more powerful server running servers as
virtual machines.

-- 
Regards,
Gregory.