Mdadm
From Ye Ole Stash
Contents |
Setup and Config
- View Current Raid layout
- cat /proc/mdstat
- Create Configuration File from CLI
- Backup existing config (/etc/mdadm.conf)
- mdadm --detail --scan > /etc/mdadm.conf
- Add
- DEVICE partitions
- MAILADDR $your_email_address
Create Raid
- Raid 1
- Raid 10
- --layout
- =n2 (near copies.(default)Gives balanced read/write performance similar to RAID 0 over 1/2 the drives.The 2 is the # of copies of the each block.)
- =f2 (better read / worse writes. This can easily spread a long sequential read across the drives at the cost of writes )
- =o2
- Further Reading
- --layout
Break/Add Raid
- Set Drive Faulty
- mdadm --fail /dev/md[1..99] /dev/sd[a-z][1..99]
- Remove Drive
- mdadm --remove /dev/md[1..99] /dev/sdf[a-z][1..99]
- Readd Drive
- mdadm --add /dev/md[1..99] /dev/sdf[a-z][1..99]
Re-Assemble Raid
Interesting Errors
- trying to create a array shows one partition as : "is too small: 0K"
- Cause: a software raid was run ontop of another software raid (ie raid 0 + 1)
- Fix `dd if=/dev/zero of=/dev/sd(a-z) bs=512 count=100` followed by a fdisk and recreate of the partition.
