OpenSolaris

Flag day: new boot sparc - PSARC 2006/525

Date: Fri, 07 Dec 2007 16:17:39 -0800
From: Jan Setje-Eilers <setje at jurassic dot eng dot sun dot com>
To: on-all at eng dot sun dot com, onnv-gate at onnv dot eng dot sun dot com
Subject: Flag day: new boot sparc - PSARC 2006/525

This Flag-day message is required reading for everyone who develops
on SPARC or maintains a SPARC build machine.

The putback of:

	6521412 PSARC 2006/525: new boot sparc

Brings dboot, ramdisk-based booting and the ramdisk miniroot to SPARC.

The dboot and ramdisk-based booting are enabling technologies for zfs
boot, fix the boot scratch memory issue once and for all, and with
modern HBAs boot significantly faster. The ramdisk miniroot
unifies the miniroot for CD, DVD, net and wanboot installs. It saves
~70Mb on the first CD.

It does not (and never intended to) deliver GRUB on SPARC. OBP continues
to be used to select boot options, the boot device and file to boot.

Information for all developers
~------------------------------

BFU has been updated to support new boot sparc. You must use an
updated BFU from the gate as of this putback. BFU'ing backwards from
these bits works for us, but is subject to the usual caveat that doing
so is never supported.

Cap-Eye Install should not be used across this putback. Users do so at
their own risk. Use of Cap-Eye Install after a BFU or upgrade will
work as it does on x86 today. Install will now include the Installed
kernel in filelist.ramdisk in /etc/boot/solaris so that the Installed
kernel is included in the boot_archive.

Information for build machine maintainers
~-----------------------------------------

BFU constructs a new generic.boot cpio archive on sparc.  You must
either build with the 't' flag or update SUNWonbld (specifically mkbfu)
after the nightly is built to be able to create this archive.  A build
of a new boot sparc workspace with an older mkbfu will result in cpio
archives which do not boot.

Additional information
~----------------------

The stand-alone failsafe can be booted by running

	boot -F failsafe

at the ok prompt. The failsafe runs entirely out of the ram-based
disk image and can be used to repair an inconsistent boot-archive
or some other damage.

BFU has been updated to install a known working failsafe archive
on the first BFU of a set of new boot sparc archives.

The ramdisk based miniroot is packed and unpacked with
root_archive(1m). Only a new-boot sparc system can pack or unpack the
compressed version of the miniroot. If pack is run on a pre new-boot
sparc system, it will produce an uncompressed image which will work as
long as the systems loading it have sufficient memory to load and run
from the larger ramdisk.

Boot performance: New boot sparc changes the workload performed during
boot. Rather than reading bits and pieces during boot, a single larger
boot_archive is loaded and then booted. Some HBA firmware does a better
job of loading a large chunk of data (the boot_archive) from disk
than others. In short, mpt and fas are now faster, qlc is neutral, glm
and isp are slower and ide depends on the drive speed.

Any bugs should be filed under solaris/kernel/boot.

We can be contacted via nb-sparc at sun dot com .

- The new-boot SPARC team