首先，我想确保大家明白这篇文章不涉及什么：
- 这不是关于创建可启动的 USB 密钥
- 这并不是简单地从 USB 启动
我想要的是拥有一个可以从 USB 记忆棒或 CF 卡启动的家用 NAS（文件）服务器。闪存驱动器的连接方式（USB、IDE 或其他方式）与本文的重点无关，重要的是：我希望整个操作系统安装都能从闪存驱动器启动和运行。我想要这种安装类型的原因是：我希望能够轻松地制作操作系统的备份副本（对闪存进行映像处理），我希望确保可以立即切换操作系统并启动它（通过更换闪存驱动器），并且我希望文件服务器上的驱动器可以独立于操作系统进行更换。
我知道可以简单地将闪存驱动器格式化为 ext2 并安装在其上。我正在寻找的是创建更强大解决方案的建议。以下是我希望做的几件事：
- 将根分区配置为 YAFF2、LogFS 或其他专为闪存驱动器设计的文件系统。
- 重新配置基本操作系统以最小化写入（/tmp 中的 ramfs 等）
请提交您的建议。我想知道 Ubuntu 是否真的适用于这种情况...
我想稍微澄清一下我的目标。常规 SSD 驱动器的固件会使用一些技巧来让驱动器长时间处于活动状态，例如：不断将写入重新分配到新扇区。USB 驱动器没有这样的固件，因此使用常规文件系统可能会很快杀死它们。我在寻找是否可以使用为闪存设计的文件系统来模拟 SSD 固件。从某种意义上说，我试图让 USB 驱动器能够以正常方式运行系统，就像它是真正的 SSD 一样。
答案1
如果您碰巧在具有 LVM 的 HDD 上安装了 Ubuntu（Ubuntu 服务器默认使用 LVM）。
该脚本在 Ubuntu Oneiric 11.10 x86_64 3.0.0-16-server 中使用以下应用程序进行了测试：
LVM version: 2.02.66(2) (2010-05-20)
Library version: 1.02.48 (2010-05-20)
Driver version: 4.20.0
grub-install (GRUB) 1.99-12ubuntu5
aufs - advanced multi layered unification filesystem. version 2.1-standalone.tree-3.0-rcN-20110620
步骤1。缩根 FS与您的 FlashDrive 大小相同或者更小。如果您的根文件系统大小与 FlashDrive 相同或更小，请跳过此步骤。
使用 Resc CD 启动并挂载您的根分区。运行以下命令：
#make the kernel realize the LVM volumes are there
lvm vgchange -a y
#Before shrinking the file system, it is good practice to check it is all in order.
# Change /dev/ubuntu/root with your root lvm partition
e2fsck -f /dev/ubuntu/root
#After the check, resize2fs can be used to shrink the file system on the LVM volume
# Change /dev/ubuntu/root with your root lvm partition. Replace 6G with your FlashDrive capacity-500Mb
resize2fs -f -p /dev/ubuntu/root 6G
#The e2fsck check command could be run again to make sure the, now significantly smaller, root file system is OK.
# Change /dev/ubuntu/root with your root lvm partition. Replace 6G with your FlashDrive capacity-500Mb
resize2fs -f -p /dev/ubuntu/root 6G
#The lvreduce command reduces the size of LVM volumes.
# Change /dev/ubuntu/root with your root lvm partition. Replace 6G with your FlashDrive capacity-500Mb
lvm lvreduce -L6G /dev/ubuntu/root
#you resided root partition !
reboot
第2步。准备闪存驱动器：迁移
看看你的旧根 UUID
blkid
#it will show something like:
#/dev/sda1: UUID="6b5085da-5b7c-4ca5-a907-1e527c87a478" TYPE="ext2"
#/dev/sda2: UUID="iZjCPX-AwGS-kEmg-zXPc-Z7ne-Xd3N-gXoPQd" TYPE="LVM2_member"
#We will need /dev/sda1's UUID later. Lets remember it (6b5085da-5b7c-4ca5-a907-1e527c87a478) for the future.
# Replace /dev/sdg with your FlashDrive. All data will be last!
fdisk /dev/sdg
make first partition (sdg1) about 500Mb as ext2/ext4
make second partition (sdg2) for example 6GB as LVM partition.
#replace ubuntu with the same LVM VolumeGroup for your root fs
#Extending VG with FlashDrive
vgextend ubuntu /dev/sdg2
modprobe dm-mirror
#Moving root partition to flash drive online :)
#Replace /dev/sdg2 with your Flash Drive's second partition
#Replace /dev/sda5 with your root drive
pvmove --verbose /dev/sda5 /dev/sdg2
#removing old root drive from VolumeGroup, so we can remove HDD from PC after manipulations. But not now.
vgreduce ubuntu /dev/sda5
#Creating boot partition.
#Replace /dev/sdg1 with your Flash Drive's first partition
mkfs -t ext4 -v /dev/sdg1
#Mounting first FlashDrive partition.
mkdir /mnt/boot
#Replace /dev/sdg1 with your Flash Drive's first partition
mount /dev/sdg1 /mnt/boot
#we will need some tools
apt-get install dump
#coping boot drive from HDD to FlashDrive first partition
#Replace /dev/sda1 (source) and /mnt/boot (destination) with your environments
(dump -0f - /dev/sda1) | ( cd /mnt/boot; restore -rf - )
#And let's not forget to restore boot sector (MBR):
# Replace /dev/sdg with FlashDrive disk path
grub-install /dev/sdg
#change UUID for /boot with the one we remember at the beginning of the Step 2 (6b5085da-5b7c-4ca5-a907-1e527c87a478).
vi /etc/fstab
#now we need to write changes to grub.
update-grub
#Now you can power off your PC.
poweroff
#Now you can replace old root FS's HDD.
#Do not forget configure your PC's BIOS to boot from your FlashDrive.
A) 如果你的 grub 已加载但无法在第一次执行时加载操作系统本文. 尝试 ls 命令来弄清楚 grub 看到了什么。
grub>ls
# Replace (hd0,msdos1) regard to previous output
grub>ls (hd0,msdos1)
# Replace (hd0,msdos1)/grub regard to previous output
grub>ls (hd0,msdos1)/grub
grub>configfile (hd0,msdos1)/grub/grub.cfg
成功启动后，更改不是永久的，因此您必须更新 grub
update-grub
B) 如果您根本看不到 grub，则使用救援 CD 进行启动。
#and install grub
#Lets figure out new name of your FlashDrive
blkid
# Replace /dev/sda with new name of your FlashDrive which system shows you
grub-install /dev/sda
#Reboot without Rescue CD and go to point A)
reboot
步骤3.AUFS 用于根文件系统在 USB 闪存驱动器上。
apt-get update
apt-get dist-upgrade
apt-get install aufs-tools
# Aufs as root with apparmor. Enter dhclient3 to complain mode
# Network interface without it wount start/
apt-get install apparmor-utils
aa-complain dhclient3
# Or disable apparmor
#/etc/init.d/apparmor stop
#update-rc.d -f apparmor remove
#aptitude remove apparmor apparmor-utils
echo aufs >> /etc/initramfs-tools/modules
现在创建 /etc/initramfs-tools/scripts/init-bottom/__rootaufs 文件并放置下一个脚本：
#!/bin/sh
# Copyright 2008 Nicholas A. Schembri State College PA USA
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see
# <http://www.gnu.org/licenses/>.
# https://help.ubuntu.com/community/aufsRootFileSystemOnUsbFlash#rootaufs_Script
# Thank you Voyage Linux for the idea, http://voyage.hk/ Great job on release 0.5
#
# Tested with 8.04.1
# tested with 9.10
# tested with debian live 6.0.1
#
# ****************************************************************************************
#
# Change log
#
# 2008.08.01 Added debugging comments in "drop to a shell" section. grub option aufs=tmpfs-debug will stop the init script.
# reviewed *********** fix fstab on tmpfs ******************
# rootaufs failed when system was booted with /dev/xxx and fstab had uuid= info.
# BlaYO pointed out the best and simplest solution was to use grep -v. Grep replaces a sed one liner.
# Add the comment block to fstab
#
# 2009.12.07 Corrected issue caused by Apparmor.
# Name changed to __rootaufs.
#
# 2011.08.19 Changed if condition to avoid issue (sh: bad number) when $aufsdebug is not set.
# Now checks exists apparmor before delete.
#
# 2011.08.20 For work correctly with Debian Live 6.0.1 (http://live.debian.net/) two lines must be removed from rc.local modification part:
# 'mount -f /ro'
# 'echo aufs-tmpfs /rw tmpfs rw 0 0 >>/etc/mtab'
#
case $1 in
prereqs)
exit 0
;;
esac
export aufs
for x in $(cat /proc/cmdline); do
case $x in
root=*)
ROOTNAME=${x#root=}
;;
aufs=*)
aufs=${x#aufs=}
case $aufs in
tmpfs-debug)
aufs=tmpfs
aufsdebug=1
;;
esac
;;
esac
done
if [ "$aufs" != "tmpfs" ]; then
#not set in boot loader
#I'm not loved. good bye
exit 0
fi
# This is a simple overview of the steps needed to use aufs on the root file system and see the /rw and /ro branches.
# initramfs init-botton script
# move the root file system to aufs/unionfs readonly /ro
# root is mounted on ${rootmnt}
# create tmpfs on /rw
# create a aufs using /ro and /rw
# put some files on the tmpfs to fix mtab and fstab
# move aufs to rootmnt to finish the init process.
# No changes to the root file system are made by this script.
#
# Why!
# This will allow you to use a usb flash drive and control what is written to the drive.
# no need to rebuild the squashfs file just to add a program.
# boot to single user mode. The system works the way you expect. boot aufs=tmpfs and no changes are written to the flash.
# run ubuntu on an eeePC .
# Install
# Install ubuntu 8.04 Hardy. Hardy has aufs installed by default
# apt-get update
# apt-get dist-upgrade
# apt-get install aufs-tools
# echo aufs >> /etc/initramfs-tools/modules
# put this file in /etc/initramfs-tools/scripts/init-bottom/rootaufs
# chmod 0755 rootaufs
# # clean up menu.lst
# update-grub
# update-initramfs -u
# vi /boot/grub/menu.lst
# add aufs=tmpfs to the default entry.
# do not add this line to single user mode.
# boot to single user mode in order to install software.
# note: if your home account is on the root file system, your files are in ram and not saved.
#
echo
echo " root-aufs: Setting up aufs on ${rootmnt} as root file system "
echo
modprobe -q --use-blacklist aufs
if [ $? -ne 0 ]; then
echo root-aufs error: Failed to load aufs.ko
exit 0
fi
#make the mount points on the init root file system
mkdir /aufs
mkdir /rw
mkdir /ro
# mount the temp file system and move real root out of the way
mount -t tmpfs aufs-tmpfs /rw
mount --move ${rootmnt} /ro
if [ $? -ne 0 ]; then
echo root-aufs error: ${rootmnt} failed to move to /ro
exit 0
fi
mount -t aufs -o dirs=/rw:/ro=ro aufs /aufs
if [ $? -ne 0 ]; then
echo root-aufs error: Failed to mount /aufs files system
exit 0
fi
#test for mount points on aufs file system
[ -d /aufs/ro ] || mkdir /aufs/ro
[ -d /aufs/rw ] || mkdir /aufs/rw
# the real root file system is hidden on /ro of the init file system. move it to /ro
mount --move /ro /aufs/ro
if [ $? -ne 0 ]; then
echo root-aufs error: Failed to move /ro /aufs/ro
exit 0
fi
# tmpfs file system is hidden on /rw
mount --move /rw /aufs/rw
if [ $? -ne 0 ]; then
echo root-aufs error: Failed to move /rw /aufs/rw
exit 0
fi
#*********** fix fstab on tmpfs ******************
# test for /dev/sdx
# this is not on the real file system. This is created on the tmpfs each time the system boots.
# The init process will try to mount the root filesystem listed in fstab. / and swap must be removed.
# the root file system must be mounted on /ro not on /
if [ "0$aufsdebug" -eq 1 ]; then
echo " root-aufs debug: Remove the root file system and swap from fstab "
echo
echo
echo " ROOTNAME $ROOTNAME "
echo " resume $resume "
echo
echo ' BlaYO pointed out that grep can be used to quickly remove '
echo ' the root file system from fstab. '
echo
echo ' Thank you BlaYO for the debug info.'
echo
fi
# old code
# I'm sure that sed can do this in one step but I want to correct on the rootname not matching the root in fstab.
#cat /aufs/ro/etc/fstab|sed -e s/$ROOTNAME/\#$ROOTNAME/ -e s/$resume/\#$resume/ >/aufs/etc/fstab
#Add the comment block to fstab
cat <<EOF >/aufs/etc/fstab
#
# RootAufs has mounted the root file system in ram
#
# This fstab is in ram and the real fstab can be found /ro/etc/fstab
# the root file system ' / ' has been removed.
# All Swap files have been removed.
#
EOF
#remove root and swap from fstab
cat /aufs/ro/etc/fstab|grep -v ' / ' | grep -v swap >>/aufs/etc/fstab
if [ $? -ne 0 ]; then
echo root-aufs error: Failed to create /aufs/etc/fstab
#exit 0
fi
# add the read only file system to fstab
#ROOTTYPE=$(/lib/udev/vol_id -t ${ROOT})
ROOTTYPE=$(cat /proc/mounts|grep ${ROOT}|cut -d' ' -f3)
ROOTOPTIONS=$(cat /proc/mounts|grep ${ROOT}|cut -d' ' -f4)
echo ${ROOT} /ro $ROOTTYPE $ROOTOPTIONS 0 0 >>/aufs/etc/fstab
# S22mount on debian systems is not mounting /ro correctly after boot
# add to rc.local to correct what you see from df
#replace last case of exit with #exit
cat /aufs/ro/etc/rc.local|sed 's/\(.*\)exit/\1\#exit/' >/aufs/etc/rc.local
echo mount -f /ro >>/aufs/etc/rc.local
# add back the root file system. mtab seems to be created by one of the init proceses.
echo "echo aufs / aufs rw,xino=/rw/.aufs.xino,br:/rw=rw:/ro=ro 0 0 >>/etc/mtab" >>/aufs/etc/rc.local
echo "echo aufs-tmpfs /rw tmpfs rw 0 0 >>/etc/mtab" >>/aufs/etc/rc.local
echo exit 0 >>/aufs/etc/rc.local
# Copyright 2008 Joaquin I. Bogado Garcia
#fix para apparmor, se desactiva y listo ( From the lethe project. )
[ -e /scripts/init-bottom/_apparmor ] && rm /scripts/init-bottom/_apparmor
[ -e /aufs/etc/init.d/apparmor ] && rm /aufs/etc/init.d/apparmor
#build remountrw
echo \#!/bin/sh >/aufs/bin/remountrw
echo mount -o remount,rw ${ROOT} >>/aufs/bin/remountrw
chmod 0700 /aufs/bin/remountrw
#build remountro
echo \#!/bin/sh >/aufs/bin/remountro
echo mount -o remount,ro ${ROOT} >>/aufs/bin/remountro
chmod 0700 /aufs/bin/remountro
# This should drop to a shell. (rewrite)
if [ "0$aufsdebug" -eq 1 ]; then
echo
echo " root-aufs debug: mount --move /aufs ${rootmnt} "
echo
echo ' root-aufs debug: init will stop here. '
echo
exit 0
fi
mount --move /aufs ${rootmnt}
exit 0
之后我们需要更改此文件的权限：
chmod 0755 /etc/initramfs-tools/scripts/init-bottom/rootaufs
步骤 4. 更改 GRUB2。
cat /etc/grub.d/10_linux|sed s/'linux_entry "${OS}" "${version}" false'/'linux_entry "RO: ${OS}" "${version}" false'/ |sed s/'"${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_EXTRA} ${GRUB_CMDLINE_LINUX_DEFAULT}"'/'"${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_EXTRA} ${GRUB_CMDLINE_LINUX_DEFAULT} aufs=tmpfs"'/ >/etc/grub.d/06_custom
sed -i.orig -e \
"/{GRUB_DISABLE_RECOVERY}\" != \"xtrue\" ]; then/s/^.*$/ \
if [ 0 ]; then/" \
/etc/grub.d/06_custom
sed -i.orig -e \
"/in_submenu=:/s/^.*$/ \
/" \
/etc/grub.d/06_custom
sed -i.orig -e \
"/\"Previous Linux versions/s/^.*$/ \
echo ''/" \
/etc/grub.d/06_custom
rm /etc/grub.d/06_custom.orig
chmod 755 /etc/grub.d/06_custom
update-grub
update-initramfs -u
答案2
使用逻辑卷管理器. 在这种情况下，您可以使用快照- 立即克隆您的系统，以便您可以轻松复制整个系统或仅在闪存驱动器之间迁移它*。
如果你想类似于“磨损均衡”， 您可以使用aufs 用于 USB 上的根文件系统flash。所以你不必使用 YAFF2 等，ext4 就可以了。
*但/启动你总是需要手动复制 + 你需要修改grub/磁盘的 UUID. 你需要救援 CD 以防万一调整大小根卷的大小与 USB 闪存的大小相同。以防 grub 读取失败本手册。
我写了手动的为了那个原因。
答案3
我也想问同样的问题并做同样的事情。这个答案有帮助吗？
这些链接看起来也很有用，尽管我不能保证信息的准确性
http://bernaerts.dyndns.org/linux/53-debian-server-compact-flash
我想，完成这些操作后，您将需要监控特定应用程序向启动闪存驱动器写入的内容。有没有简单的方法可以查看向给定驱动器写入的内容？