A linux utility used to manage software RAID devices.
Questions tagged [mdadm]
336 questions
51
votes
8 answers
How can I make mdadm auto-assemble RAID after each boot?
I successfully created a RAID (mirroring) by utilizing mdadm. However, I must run the following commands after each boot:
mdadm --stop --scan // to stop /dev/md127 - I don't know where the number 127 even comes from
mdadm --assemble --scan // to…
38
votes
10 answers
How to get an inactive RAID device working again?
After booting, my RAID1 device (/dev/md_d0 *) sometimes goes in some funny state and I cannot mount it.
* Originally I created /dev/md0 but it has somehow changed itself into /dev/md_d0.
# mount /opt
mount: wrong fs type, bad option, bad superblock…
Jonik
- 5,940
34
votes
4 answers
How do I reactivate my MDADM RAID5 array?
I've just moved house which involved dismantling my server and re-connecting it. Since doing so, one of my MDADM RAID5 arrays is appearing as inactive:
root@mserver:/tmp# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4] [linear] [multipath]…
Jon Cage
- 2,627
32
votes
11 answers
Simple mdadm RAID 1 not activating spare
I had created two 2TB HDD partitions (/dev/sdb1 and /dev/sdc1) in a RAID 1 array called /dev/md0 using mdadm on Ubuntu 12.04 LTS Precise Pangolin.
The command sudo mdadm --detail /dev/md0 used to indicate both drives as active sync.
Then, for…
Deltik
- 19,971
32
votes
6 answers
Does RAID1 increase performance with Linux mdadm?
I have a cheap 2-bay NAS with a 2TB HDD. To be robust against disk failure, I'm thinking of buying a second 2TB HDD and putting it in RAID1 with Linux mdadm. The file system is ext4.
Will this increase or decrease the performance of the NAS? What…
Jesse
- 843
- 2
- 10
- 16
28
votes
4 answers
How-to change the name of an MD device (mdadm)
Here is the output from mdadm -Esv:
ARRAY /dev/md127 level=raid0 num-devices=2 UUID=d89d9d45:9a420812:c44c77eb:7ee19756
devices=/dev/sdb8,/dev/sda8
This is a v0.90 array. The question is as follows: how does mdadm assign the name for an…
XXL
- 1,489
18
votes
3 answers
How to force mdadm to stop RAID5 array?
I have /dev/md127 RAID5 array that consisted of four drives. I managed to hot remove them from the array and currently /dev/md127 does not have any drives:
cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4]…
matt
- 748
15
votes
7 answers
Adding drives to a RAID 10 Array
How would I grow a RAID10 array using mdadm?
Obviously I would need to add 2 drives at a time, or would it have to be 4 drives?
I have a feeling its just a bad idea.
Or would be just wiser to just opt for RAID5?
stuartc
- 615
13
votes
6 answers
How to find which drives are mirrored within a RAID-10 array?
I have a home media server running on openSUSE 12.2. I'm using eight 2TB drives in a RAID-10 configuration. I deliberately bought two different types of drives: four Seagate Barracuda Green and four Western Digital Red. My goal is to configure the…
CapnBFG
13
votes
2 answers
Resize underlying partitions in mdadm RAID1
I have a home built NAS, and I need to slightly reconfigure some of my drive usage.
I have an mdadm RAID1 composed of two 3TB drives. Each drive has one ext3 partition that uses the entire drive. I need to shrink the ext3 partition on both…
kyork
- 261
12
votes
3 answers
How does one enable “--write-mostly” with Linux RAID?
Unfortunately the mdadm and mdadm.conf man pages are not quite up to par. I would like to enable the --write-mostly flag for my RAID, but neither the man pages nor the internet will tell me how. I am not aware of any place to put default arguments…
user76871
- 958
11
votes
3 answers
mdadm RAID Fast Setup with Empty Drives?
I am recreating some RAID5 disks as RAID6 with mdadm. There is no data on the drives that I care about.
Setting up RAID takes a while to setup the shape - I accept that when there there is data that needs to be striped and parity calculated,…
Paul
- 61,193
11
votes
1 answer
How can I remove this "zombie" mdadm array?
Admittedly I'm not too familiar with MDADM. I recently set up an array for a NAS, but incorrectly sized the partitions in my setup script, and need to remove the array, re-partition the disks, and re-create the array.
In my Googling, I found the…
Ralph
- 419
10
votes
1 answer
Is it safe to "use" to disk if extended smart check is in progress?
As simple as the title suggests.
/dev/sda is a unit from /dev/md127 - RAID1 drive.
I'm currently running a test - started a smartctl -t long /dev/sda.
Afterwards, I started to copy files over WinSCP (SFTP) to the mounted mdadm array.
I didn't notice…
tomsseisums
- 779
10
votes
3 answers
Is it safe to put harddisks of a md-software-raid to standby?
I have a home-fileserver with 6 desktop harddisks in a md-raid.
The server isn't accessed a lot, so I think it would be good for the harddrives to go in standby-mode after some idle time (e.g. with the hdparm -S or hd-idle command).
Is this safe…
Dani31
- 123