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Eric J.
Asked: 2010-05-15 10:39:22 +0800 CST

Ubuntu Software RAID 0 on AWS Does Not Survive Reboot

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I'm experimenting with creating a software RAID 0 device from 4 EBS volumes on Ubuntu 9.10 running at Amazon AWS following this guide:

http://alestic.com/2009/06/ec2-ebs-raid

The device appears (and according to SysBench is 3.5x faster than a regular attached EBS volume).

Problem is, when I reboot the instance, all files on the RAID device are gone. The device is available and mounted where expected, but contains no files. I am able to write new files to it, which survive until the next reboot.

EDIT:

Here's the script I use to setup the RAID. It writes to /etc/fstab and /etc/mdadm.conf

#!/bin/bash
# Create RAID 

volumes=4
devices="/dev/sdj /dev/sdk /dev/sdl /dev/sdm"
devicearray=($devices)
volumeids="vol-11111111 vol-22222222 vol-33333333 vol-44444444"

yes | sudo mdadm          \
  --create /dev/md0       \
  --level 0               \
  --metadata=1.1          \
  --raid-devices $volumes \
  $devices

echo DEVICE $devices | sudo tee /etc/mdadm.conf 
sudo mdadm --detail --scan | sudo tee -a /etc/mdadm.conf
sudo mkfs.xfs /dev/md0

mountpoint=/mnt/raid
echo "/dev/md0 $mountpoint xfs noatime 0 0" | sudo tee -a /etc/fstab
sudo mkdir $mountpoint
sudo mount $mountpoint

/etc/fstab

# /etc/fstab: static file system information.
# <file system>                                 <mount point>   <type>  <options>       <dump>  <pass>
proc                                            /proc           proc    defaults        0       0
/dev/sda1                                       /               ext3    defaults        0       0
/dev/sdb                                        /mnt            ext3    defaults        0       0
/dev/md0 /mnt/raid xfs noatime 0 0

/etc/mdadm.conf

DEVICE /dev/sdj /dev/sdk /dev/sdl /dev/sdm
ARRAY /dev/md0 level=raid0 num-devices=4 metadata=01.01 name=ip-10-194-5-235:0 UUID=67392a94:553fddec:4bc8e5c7:8d25c3ca
ubuntu amazon-ec2 raid amazon-ebs

3 Answers

  1. Best Answer

    It seems that extra white space after the device name in mdadm caused the issue. Editing away extra white space and repeating the procedure resolved the problem.

    • 2

  2. Add rw you fstab line. Like this, /dev/md0 /mnt xfs rw,noatime 0 0

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  3. I know this question is really old but I want to help those who will stumble on this just like I did. I was facing the exact same problem and ended up doing 4 things to make my RAID0 survive reboots(Ubuntu 12.04).

    1) Entry in the /etc/fstab file: /dev/md0 /mnt/md0 auto defaults,nobootwait,comment=cloudconfig 0 2

    2) echo 'DEVICE /dev/sdb /dev/sdc' > /etc/mdadm/mdadm.conf,

    3) mdadm --detail --scan >> /etc/mdadm.conf

    4) sudo update-initramfs -u

    With this I was able to handle several reboots of my machine and RAID0 came up every time. Hope this helps.

    • 0