[[PageOutline]]

 = about Software RAID =

 = boot loader =

 = mdadm =
 == Ubuntu ==
 * [http://www.ubuntulinux.jp/getubuntu/releasenotes/810overview Ubuntu 8.10 技術概要 | Ubuntu Japanese Team] #起動時のデグレードRAID設定

 * /etc/initramfs-tools/conf.d/mdadm
{{{
# BOOT_DEGRADED:
# Do you want to boot your system if a RAID providing your root filesystem
# becomes degraded?
#
# Running a system with a degraded RAID could result in permanent data loss
# if it suffers another hardware fault.
#
# However, you might answer "yes" if this system is a server, expected to
# tolerate hardware faults and boot unattended.

BOOT_DEGRADED=false
}}}
 * /etc/mdadm/mdadm.conf
{{{
# instruct the monitoring daemon where to send mail alerts
MAILADDR root
}}}
 * /etc/default/mdadm
{{{
# AUTOCHECK:
#   should mdadm run periodic redundancy checks over your arrays? See
#   /etc/cron.d/mdadm.
AUTOCHECK=true

# START_DAEMON:
#   should mdadm start the MD monitoring daemon during boot?
START_DAEMON=true
}}}
   * /etc/cron.d/mdadm
{{{
# By default, run at 01:06 on every Sunday, but do nothing unless the day of
# the month is less than or equal to 7. Thus, only run on the first Sunday of
# each month. crontab(5) sucks, unfortunately, in this regard; therefore this
# hack (see #380425).
6 1 * * 0 root [ -x /usr/share/mdadm/checkarray ] && [ $(date +\%d) -le 7 ] && /usr/share/mdadm/checkarray --cron --all --quiet
}}}

 === dpkg-reconfigure mdadm ===
 * [ ... ] がデフォルト値

 * sudo dpkg-reconfigure mdadm
   1. /etc/default/mdadm AUTOCHECK
{{{
 ┌───────────────────────────┤ Configuring mdadm ├
 │                                                                           │
 │ If your kernel supports it (>> 2.6.14), mdadm can periodically check the  │
 │ redundancy of your MD arrays (RAIDs). This may be a resource-intensive    │
 │ process, depending on your setup, but it could help prevent rare cases    │
 │ of data loss. Note that this is a read-only check unless errors are       │
 │ found; if errors are found, mdadm will try to correct them, which may     │
 │ result in write access to the media.                                      │
 │                                                                           │
 │ The default, if turned on, is to run the checks on the first Sunday of    │
 │ every month at 01:06 o'clock.                                             │
 │                                                                           │
 │ Should mdadm run monthly redundancy checks of the MD arrays?              │
 │                                                                           │
 │                   [<Yes>]                      <No>                       │
 │                                                                           │
 └──────────────────────────────────────
}}}
   1. /etc/default/mdadm START_DAEMON
{{{
  ┌──────────────────────────┤ Configuring mdadm ├
─│                                                                         │
  │ The MD (RAID) monitor daemon sends email notifications in response to   │
  │ important MD events (such as a disk failure). You probably want to      │
  │ enable it.                                                              │
  │                                                                         │
  │ Do you want to start the MD monitoring daemon?                          │
  │                                                                         │
  │                   [<Yes>]                      <No>                     │
  │                                                                         │
  └──────────────────────────────────────
}}}
   1. /etc/mdadm/mdadm.conf MAILADDR
{{{
   ┌─────────────────────────┤ Configuring mdadm ├─
─ │ Please enter the email address of the user who should get the email   │
   │ notification for important MD events.                                 │
   │                                                                       │
   │ Recipient for email notifications:                                    │
   │                                                                       │
   │ root_________________________________________________________________ │
   │                                                                       │
   │                                <Ok>                                   │
   │                                                                       │
   └─────────────────────────────────────
}}}
   1. /etc/initramfs-tools/conf.d/mdadm BOOT_DEGRADED
{{{
 ┌───────────────────────────┤ Configuring mdadm ├
 │                                                                           │
 │ If your root filesystem is on a RAID, and a disk is missing at boot, it   │
 │ can either boot with the degraded array, or hold the system at a          │
 │ recovery shell.                                                           │
 │                                                                           │
 │ Running a system with a degraded RAID could result in permanent data      │
 │ loss if it suffers another hardware fault.                                │
 │                                                                           │
 │ If you do not have access to the server console to use the recovery       │
 │ shell, you might answer "yes" to enable the system to boot unattended.    │
 │                                                                           │
 │ Do you want to boot your system if your RAID becomes degraded?            │
 │                                                                           │
 │                    <Yes>                      [<No>]                      │
 │                                                                           │
 └──────────────────────────────────────
}}}
   * apply settings...
{{{
 * Stopping MD monitoring service mdadm --monitor                        [ OK ]
Generating array device nodes... done.
 Removing any system startup links for /etc/init.d/mdadm-raid ...
update-initramfs: Generating /boot/initrd.img-2.6.24-24-server
Warning: LBA32 addressing assumed
Added Linux *
Added LinuxOLD
The Master boot record of  /dev/sda  has been updated.
Warning: /dev/sdb is not on the first disk
The Master boot record of  /dev/sdb  has been updated.
2 warnings were issued.
 * Starting MD monitoring service mdadm --monitor                        [ OK ]
}}}