A linux utility used to manage software RAID devices.

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6
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3answers
7k views

explain md's raid10,f2

I know how most of the various RAID's work. But I stumbled on the recommended raid10,f2 mode while researching linux software raid. I don't really understand how it works on 2 or 3 disks. could ...
33
votes
4answers
15k views

Recover RAID 5 data after created new array instead of re-using

Folks please help - I am a newb with a major headache at hand (perfect storm situation). I have a 3 1tb hdd on my ubuntu 11.04 configured as software raid 5. The data had been copied weekly onto ...
3
votes
2answers
3k views

Linux RAID 1: How to make a secondary HD boot?

I have the following RAID 1 on a Centos 6.5 server: # cat /proc/mdstat Personalities : [raid1] md0 : active raid1 sdb1[3] 974713720 blocks super 1.0 [2/1] [_U] bitmap: 7/8 pages [28KB], ...
14
votes
5answers
12k views

Best way to grow Linux software RAID 1 to RAID 10

mdadm does not seem to support growing an array from level 1 to level 10. I have two disks in RAID 1. I want to add two new disks and convert the array to a four disk RAID 10 array. My current ...
11
votes
2answers
16k views

How do I move a Linux software RAID to a new machine?

I have a newly built machine with a fresh Gentoo Linux install and a software RAID 5 array from another machine (4 IDE disks connected to off-board PCI controllers). I've successfully moved the ...
2
votes
1answer
2k views

How to boot after RAID failure (software RAID)?

Previously I had a software raid set up using (mdadm) of drives sda and sdb. sdb failed and the only way to reboot the system was by unplugging the second hard drive. Now I've added fresh sdb and sdc ...
3
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1answer
2k views

Removing a device in “removed” state from Linux software RAID array

My workstation has two disks(/dev/sd[ab]), both with similar partitioning. /dev/sdb failed, and cat /proc/mdstat stopped showing the second sdb partition. I ran mdadm --fail and mdadm --remove for ...
1
vote
1answer
97 views

Disabling damaged RAID 1 to read from healthy HDD

One of the HDDs in my software RAID 1 on a dedicated server is damaged. The customer support is slow to respond. I would like to transfer all data I need to another server, but file access is ...
8
votes
4answers
4k views

Using 4k drives with md/LVM/dm-crypt

I know that I have to align my 4k drives by a multiple of 8 sectors, but what about md-RAID / LVM / dm-crypt? How do I tell these layers that my drive is 4k? If they don't respect the 4k sector size, ...
1
vote
3answers
211 views

Hard disk / SSDs - detection and handling of errors - is silent data corruption reliably prevented?

When an error occurs on a drive, is it correct to assume that it will always be detected and reported to the OS (if software RAID such as mdadm) or RAID controller (if hardware RAID) as a failed read ...
6
votes
4answers
14k views

How to create a software raid5 array without a spare

I am trying to create a software raid5 array using mdadm: $ linux # mdadm --create --verbose /dev/md0 --level=5 --raid-devices=4 --spare-devices=0 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1 mdadm: ...
3
votes
2answers
1k views

Odd mdadm output: --examine shows array state failed, --detail shows everything clean

The setup: 8 disks in a mdadm-managed RAID5 array (/dev/md0, made from /dev/sdc through /dev/sdj). One disk (/dev/sdh) is showing SMART errors (increasing pending sector count) so I'm looking to ...
8
votes
1answer
5k views

mdadm and 4k sectors (advanced format)

There are numerous questions on Serverfault about aligning 4k sectors disks, but one thing is not really clear to me yet. I successfully aligned my RAID1+LVM. One of the things I did was use mdadm ...
4
votes
1answer
398 views

3 drives fell out of Raid6 mdadm - rebuilding?

i had an mdadm raid6 array with 13x1TB drives. Within 10 minutes 3 of these drives fell out of the array... we assume bad cable to the controller card and replaced, however now we need to get the ...
2
votes
0answers
4k views

How to recover an mdadm array on Synology NAS with drive in “E” state?

Synology has a customized version the md driver and mdadm toolsets that adds a 'DriveError' flag to the rdev->flags structure in the kernel. Net effect - if you are unfortunate enough to get a array ...
1
vote
2answers
9k views

mdadm rebooted, array missing? can't assemble?

Not sure what is going on with my Array. I rebooted ubuntu 12.04.1 and got a error on startup that fstab couldn't mount the filesystem UUID I have for my mdadm array. After running a few commands a I ...
1
vote
2answers
347 views

Ubuntu 12.04 Server Software RAID1 - Faulty Spare - Smart Output Passed - Confused

I think I'm having an issue with one of the hard drives on my array and I'm just trying to troubleshoot what's happening. Its saying Faulty Spare and then after reboot it just says removed: ...
1
vote
3answers
2k views

Creating a partitioned raid1 array for booting a debian squeeze system

I'd like to have the following raid1 (mirror) setup: /dev/md0 consists of /dev/sda and /dev/sdb I created this raid1 device using mdadm --create --verbose /dev/md0 --auto=yes --level=1 ...
0
votes
3answers
78 views

In a software RAID1, why does tune2fs -c 0 /dev/sda1 not throw an error but change is not seen in tune2fs -l /dev/sda1?

The Title pretty much says it all. Turn off mount count fsck seems to succeed: tune2fs -c 0 /dev/sda1 tune2fs -c 1 /dev/md0 But listing out via tune2fs -l /dev/sda1 shows mount count is set back ...
0
votes
1answer
113 views

How to have automatic file system checks for Linux Software Raid?

In a Linux Software raid, what is the best practice for periodically having the filesystems checked? With single drive or hardware raid, tune2fs -c 5 -i 1w /dev/sda1 means check the filesystem every ...
4
votes
1answer
1k views

Cannot install grub, segmentation fault, unable to identify filesystem, superfluous RAID member, found two disks with same index — Debian 7

A server was recently transported from location A to B, a long journey that took six months. Things have gone wrong due to nothing being labeled prior to shipment. Yes, I know --- it was done by ...
4
votes
4answers
3k views

apt-get update mdadm scary warnings

Just ran an apt-get update on one of my dedicated servers to be left with a relatively scary warning: Processing triggers for initramfs-tools ... update-initramfs: Generating ...
3
votes
4answers
2k views

Slow disk I/O in KVM with LVM and md raid5

I have been battling with a kvm setup under debian for two weeks now, specifically with guest I/O disk performance. The system: -Supermicro 1018d-73mtf (X10SL7-F motherboard) -16GB ECC/UB -Intel ...
3
votes
1answer
1k views

Growing a RAID5 using mdadm with multiple drives?

I have a RAID5 array that consists of 3, 2TB drives. I want to add 2 more drives. The tutorials involve adding a single drive to an array, such as this: https://raid.wiki.kernel.org/index.php/Growing ...
3
votes
1answer
129 views

Is there any way to build a linux software raid system without all drives?

I'm building a raid1 (ok it will probably be a raid10,f2 but the difference with 2 drives... isn't much) system with 2 1TB drives. However, 1 of the drives I've ordered is bad so I'm RMA-ing it. I'm ...
2
votes
2answers
682 views

Remake SW RAID1 from a new HDD and an old HDD with bad blocks

I have a SW RAID1 and I just replaced /dev/sda with a new HDD as the old one failed. Now, upon trying to recreate the RAID array I discovered that the "good" HDD (/dev/sdb) has bad blocks with prevent ...
2
votes
3answers
2k views

Can I convert a raid10 array to raid0?

I have created a raid10 array using mdadm. Metadata version is 1.2. I want to convert this to a raid0 array, is it possible? P.S. I am having terabytes of data, I want to avoid copying the data over. ...
2
votes
2answers
497 views

mdadm fail, disk won't show up

One of my disks failed in my raid array: cat /proc/mdstat: Personalities : [raid1] md1 : active raid1 sda2[2](F) sdb2[1] 488086720 blocks [2/1] [_U] md0 : active raid1 sda1[0] sdb1[1] ...
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vote
0answers
96 views

How to best use Amazon's “ephemeral” SSD devices under Linux? [closed]

Amazon attaches "ephemeral" SSD device(s) to most of the instace-types -- these are included in the cost of VM, are fast, but any data on them is lost, when the VM is shut down. How to make the best ...
1
vote
2answers
4k views

Grub rescue, will not boot from mdadm RAID, no such disk or device — mduuid wrong?

I am running a 14 disk RAID 6 on mdadm behind 2 LSI SAS2008's in JBOD mode (no HW raid) on Debian 7 in BIOS legacy mode. Grub2 is dropping to a rescue shell complaining that "no such device" exists ...
1
vote
1answer
259 views

How to display/define Mirror/Stripping pairs with mdadm

I want to make a standard linux software Raid10 over 4 HDD. The server has 4HDDs, 2 pairs from different vendors in order to avoid batch problems. I want to have the mirror over two different ...
1
vote
1answer
475 views

mdadm superblock hiding/shadowing partition

Short version: Is it safe to do mdadm --zero-superblock /dev/sdd on a disk with a partition (dev/sdd1), filesystem and data? Will the partition be mountable and the data still there? Longer ...
1
vote
1answer
726 views

What parameters to mdadm, to re-create md device with payload starting at 0x22000 position on backing storage?

I try to recover from mdadm raid disaster, which happened when moving from ubuntu server 10.04 to 12.04. I know the correct order of devices from dmesg log, but given this information, I still cannot ...
1
vote
4answers
2k views

mdadm assembles with drives instead of partitions

I have a RAID 5 array built from partitions on 5 drives - /dev/sda1, /dev/sdb1, /dev/sdc1, /dev/sdd1, and /dev/sde1. When I assemble the array manually, it works fine. Unfortunately, there seem to ...
1
vote
1answer
509 views

How to create partition when growing raid5 with mdadm

I have 4 drives, 2x640GB, and 2x1TB drives. My array is made up of the four 640GB partitions and the beginning of each drive. I want to replace both 640GB with 1TB drives. I understand I need to 1) ...
0
votes
2answers
40 views

mdadm - RAIDs of partitions or partitions of RAID?

If using entire drives for an mdadm RAID which will be the boot device as well, is it more correct / standard to: 1) Configure the RAID out of partitions that encompass the whole drive (like ...
0
votes
1answer
141 views

System wont boot from degraded RAID6

I have a Debian Wheezy with 3 Partitions as RAID6. MD0 is for Root and OS, MD1 is for SWAP and MD2 for Files. While copy files to MD2 the system reports kernel panic and halts. I have had shutdown on ...
0
votes
1answer
104 views

Growing mdadm raid1 live; metadata 1.1 and 1.2

I can find a lot of posts about growing a mdadm RAID1 array on a live system. After growing the partitions, everybody simply says to do: mdadm --grow /dev/md1 --size=max But that doesn't work, ...
0
votes
2answers
2k views

2nd drive in RAID 1 keeps failing

I have a bit of a problem here. I have a Ubuntu Linux server set up with 2 SAS drives in a software RAID 1 (created with mdadm). The RAID will run fine for a day, I can do cat /proc/mdstat and it ...
-1
votes
1answer
208 views

Disaster recovery. MDADM/LVM2 Some advance but stuck on final mount

We made a stupid upgrade on a running server using wrong repositories and the system became totally unbootable. The system, a SLES 11 we used a openSuse repository to upgrade, and everything went ...