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Questions tagged [raid6]

31 questions
13
votes
5 answers

Can RAID 1 have more than two drives?

Recently I had a discussion with a teacher of mine. He was claiming that you could set up RAID 1 with five drives and that the data would be mirrored over all of these drives. I told him a RAID 1 with 5 drives wouldn't work like that. It would be a…
Mad_piggy
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7
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1 answer

Fail device in md RAID when ATA stops responding

I had created five 1TB HDD partitions (/dev/sda1, /dev/sdb1, /dev/sdc1, /dev/sde1, and /dev/sdf1) in a RAID 6 array called /dev/md0 using mdadm on Ubuntu 14.04 LTS Trusty Tahr. The command sudo mdadm --detail /dev/md0 used to show all drives in…
Deltik
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7
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3 answers

Is RAID1 or similar needed for btrfs/ZFS to protect against bit rot?

I'm running a file server using Linux software raid, set up as raid6. As filesystem I've chosen btrfs. However, I'm not using btrfs own raid6 implementation as it's not very stable yet. So basically, I'm using raid on the block level of things.…
user333556
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7
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2 answers

Why does RAID 6 require at least 4 disks?

For a non-degraded RAID 6 array, why do most implementations and documentation require at least 4 drives? Why can't it have 3 disks, for 1 data and 2 parity blocks per stripe? Why force a minimum of 2 data and 2 parity? I realise you can make a…
BeowulfNode42
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7
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3 answers

Btrfs over mdadm RAID6?

I have a Btrfs RAID 6** array, and I currently have enough free space to rebuild it to avoid the data loss bug that currently affects the filesystem with this RAID level. My idea is to rebuild the array using mdadm and format the md device with…
Benjamin Dubois
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5
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1 answer

Windows Server Software RAID 6

I want to set up a software RAID 6 configuration, but in Windows Server 2008 it only lets me do up to RAID 5. In Server 2012 I saw they have this new thing called "Storage Spaces" which sounds neat, but I assume you can still set up a basic RAID 5…
Nalandial
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3
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0 answers

how to force mdadm to sync to device after raid6 repair and how to get number of errors?

The Question After a component device suffered unexpected bit-flip, and after a raid6 repair was successfully performed on the raid device, how to force mdadm to sync the changes from buffer(?) back onto the component device? And how to monitor when…
Max-Julian Pogner
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2
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2 answers

Is it possible to convert a btrfs RAID5 to a RAID6 with the same disks without losing data?

How would I convert an existing RAID5 (single parity) btrfs setup to a dual parity RAID6 configuration given enough free available disk space, using the same disks, without swapping out data ? Basically that should just be removing a disk and…
Arc
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2
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1 answer

mdadm: superblock on /dev/sdd1 doesn't match others - assembly aborted

OS: Debian Squeeze Kernel: 2.6.32-5-amd64 mdadm version: 3.1.4 (31 August 2010) mdarrays md1 = raid1 (this is working) (devices: /dev/sd[fg]1) md0 = raid6 (previously raid5, now failing to start) (devices:…
Waxhead
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2
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1 answer

Managing raid6 device with pacemaker

I am setting up 4 hosts, each exporting one local storage device over iscsi with target. Every other hosts imports it such that each host has concurrent access to all 4 each storage devices. I built a LVM shared volume group that includes all these…
Nykau
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2
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Raid6 mdadm reshape operation interrupted - now cannot mount or examine

Edit: Once the reshape finished the drive became fully accessible again. I had a power failure while a raid6 array was being reshaped, and now certain operations cannot be run against it, including mounting or mdadm --examine. To add to my woes, one…
Jonathan Cremin
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2
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0 answers

Up to which point (disk size) is Raid 6 safe to use?

I have been reading a lot of warnings about Raid-6 becoming less and less safe to use due to the storage amount per disk as well as array sizes increasing. What are the best practice limits/when does it make sense to take the economical hit of using…
user2693017
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2
votes
1 answer

mdadm shows inactive raid0 array instead of degraded raid6 after disk failure

I've been running an Ubuntu 18.04 system with an 8-disk raid 6 array, that crashed while having a faulty disk (I only noticed that there was a faulty disk after the crash). The raid array has survived multiple Ubuntu installs, so it's not the first…
D.F.
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1
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1 answer

LVM2 RAID6 CentOS 7 not working

I have a server with 4 spare 6 Tb disks. I want to set up RAID6 on these four disks. It is well understood that 4 is the minimum one needs to set up RAID6. No matter what I pass to LVM2, I get locked out: [root@mybox /]# vgdisplay --- Volume…
volvox
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1
vote
1 answer

Online Drive Replacement: BTRFS with RAID 6

on a testing machine I installed four HDDs and they are configured as RAID6. For a test I removed one of the drives (/dev/sdk) while the volume was mounted and data was written to it. This worked well, as far as I can see. Some I/O errors were…
Oliver R.
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