gentoo squashfs portage under overlay(fs) 記

cal22cal

注意:-
呢嗰 squashfs 响 btrfs 唔 work,
因為 emerge --sync , emerge-webrsync 嘅 rsync 嗰時有問題
overlay files/dir 而家用緊 ext4, / 係 btrfs

2006 年嘅 post, 好多嘢唔同曬
https://forums.gentoo.org/viewtopic-t-465367.html
原本係用 aufs, 太多嘢, 冇搞佢
自從新啲嘅 kernel 有 overlay(fs) 就諗住玩吓
gentoo user "mv" 接手 main 個 project 叫 squashmount,
又唔想响部機 install portage overlay
咁就响部 vm fetch mv overlay, dl & test
將啲 procedures & ebuild, 由 vm 機抄返出嚟 /usr/local/portage/...

要嘅係 mv overlay 嘅

1. /var/lib/layman/mv/sys-fs/squashmount/squashmount-12.1.1.ebuild
   
2. /var/lib/layman/mv/sys-fs/squashfs-tools/squashfs-tools-4.3.ebuild
   
3. /var/lib/layman/mv/app-shells/runtitle/runtitle-2.7.ebuild

複製代碼

1. kernel config
   
2. Device Drivers --->
   
3.   Block Devices --->
   
4.     <M> Loopback device support
   
5. File systems  --->
   
6.    [M] Overlay filesystem support
   
7.    
   
8. https://wiki.gentoo.org/wiki/SquashFS#Kernel
   
9.        

複製代碼

1. edit /etc/portage/package.use
   
2. sys-fs/squashfs-tools xz lz4 lzma lzo xattr
   
3. time emerge -av Term-ANSIColor File-Which squashmount squashfs-tools

複製代碼

用 gentoo/mv 個 squashfs-tools, 自己決定, 問題不大
有問題, 玩得嘅, 應該自己識點 fix.

如果 /usr/portage 有啲特別嘢, 搞過 /etc/fstab 還原返,
backup /usr/portage ( 可以唔做, 做咗冇壞 )
重要嘅係 /usr/portage 只係有啲 ebuild 同 dir structures,
edit /etc/portage/make.conf
嗰啲 DISTFILES PKGDIR 全部要搬曬出去

mv /etc/squashmount.pl /etc/squashmount.pl.org
個 org 有好多 example, 慢慢睇, 用呢個 min conf.

1. cat /etc/squashmount.pl
   
2. 
   
3. #!/usr/bin/perl (this is only for editors)
   
4. 
   
5. # The tools which we have installed; if possible only the first in this list
   
6. # is used, but the others are a fallback if that fails.
   
7. 
   
8. @order = ( overlay ); # 舊啲嘅 kernel 係 overlayfs, chk 清楚
   
9. 
   
10. # Even if we define following is empty it is convenient to use
    
11. # this local variable throughout, so that we can simply change it:
    
12. 
    
13. DIFF => 1;
    
14. RESQUASH_ON_START => 1;
    
15. 
    
16. push(@mounts, {
    
17.    TAG => 'portage',
    
18.    DIR => '/usr/portage', # 係响 btrfs partition
    
19.    FILE => '/no-XXX/portage.sqfs', # /no-XXX/ 係响 ext4 partition
    
20.    CHANGES => '/no-XXX/portage.changes',
    
21.    WORKDIR => '/no-XXX/portage.squashfs.workdir',
    
22.    READONLY => '/no-XXX/portage.readonly',
    
23.    THRESHOLD => '40m', # resquash on umount if 40 megabytes changed
    
24.    COMPRESSION => 'lz4'   
    
25. });
    
26. @umount;
    
27. 1;

複製代碼

@order = ( overlay ); 舊啲嘅 kernel 係 overlayfs
可以係第貳啲, 睇 /etc/squashmount.pl.org
no-XXX 要改去, 自己要指去嘅地方
注意最後嗰行係 1;

第一次 run
/etc/init.d/squashmount -d start
-d for debug info
佢會 build squash file /no-XXX/portage.sqfs  ~= 110MB
之後會剷曬 /usr/portage/*
同埋 create /no-XXX/portage.* directories
用 overlay(fs) 嚟 mount /usr/portage
所以如果玩第貳啲 dir, 記得 backup 先,
或者响 vm 試清楚先好去 production
/etc/fstab 唔洗有特別 /usr/portage ... 個 entry

#df -hT 會有 2 個 new mount, loop 同 overlay

1. /dev/loop0     squashfs  104M  104M     0 100% /home/PORTAGE_FILES/portage.readonly
   
2. overlay        overlay   2.6T  435G  2.0T  18% /usr/portage

複製代碼

# mount

1. /home/PORTAGE_FILES/portage.sqfs on /home/PORTAGE_FILES/portage.readonly type squashfs (ro,noatime)
   
2. overlay on /usr/portage type overlay (rw,noatime,lowerdir=/home/PORTAGE_FILES/portage.readonly,upperdir=/home/PORTAGE_FILES/portage.changes,workdir=/home/PORTAGE_FILES/portage.squashfs.workdir)

複製代碼

rc-update add squashmount default
如果 > 40MB changes, shutdown 嗰陣會 recompress,
我部垃圾機都只係用多 ~ 1 分鐘
reboot && good luck

希望冇打漏/錯嘢, 知道先改返