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Questions tagged [raid1]

RAID 1 or Mirrored RAID uses two or more disks that store the same data.

RAID Level 1 or mirrored RAID uses two or more disks that store the same data. One disk is mirrored to the other. Write speeds are the same as using one disk, and read speeds are twice as much.

RAID 1 is used when reliability needs to be higher than normal.

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mdadm: Which disk is being rebuilt?

I noticed my software RAID1 degraded, and wanted to figure out which of the two disks in the array is being rebuilt/re-synced since they both show as being up. I am hoping someone can shed some light on this, if it's even possible to figure out…
Paul
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DegradedArray event on /dev/md1

This morning I got this message: This is an automatically generated mail message from mdadm running on A DegradedArray event had been detected on md device /dev/md1. Faithfully yours, etc. P.S. The /proc/mdstat file currently contains the…
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Can I create a "soft" RAID1 array without nuking data?

I've just bought two 1.5TB disks with the aim of creating a 1.5TB RAID1 array. In my infinite lack of wisdom (and a lack of space inside the computer - it already had 6 disks), I stuck one in, formatted it to EXT4 and proceeded to copy data all over…
Oli
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Why did my zpool replace never finish and what should I do now?

I have a ZFS zpool with two disks in a mirror configuration, da0 and da1. da1 failed, and so I replaced it with da2 using zpool replace BearCow da1 da2 This ran for a few hours, during which zpool status showed that the array was being resilvered.…
Josh
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Can I build a RAID 5+1 system?

I must say I already found a similar question on this platform, but the context was different, so I'm trying by myself. My idea is as follows: I have 4 disks, 3 of them are the same capacity, and the fourth one has twice the capacity of either of…
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How to add hot spare to software RAID1?

I have a CentOS 7 server. It is running a software RAID 1 mirroring three disks. I want to add a 4th disk to act as a hot spare. My intention is that in the event of a failure of one of the three disks being mirrored that the hot spare would…
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Amazon AWS Ephemeral disks and RAID1

Some AWS instances have "ephemeral disks" attached, which are much faster than EBS. But ephemeral disks will be blank and uninitialised when your instance is stopped and started. The data on disk generally survives an instance reboot…
Criggie
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mdadm software RAID isn't assembled at boot during initramfs stage

First, I prefer to mention I've found and read this. I'm running Debian Jessie with a standard 3.16 kernel. I've manually defined a RAID1 array. But it is not assembled automatically at boot time. And thus, systemd falls back to some degraded shell…
Sun Wukong
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Is it possible to enable RAID 1 on an already in-use HP Proliant DL380 G5

I have a HP Proliant DL380 G5 with two HDDs in RAID 0 (Stripe)(72GB+72GB). It has been running Windows Server for quite a while now and has 30GB of occupied space on a stripted volume. I've now purchase two 72GB HDDs more (same as the one's already…
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How to delete removed devices from a mdadm RAID1?

I had to replace two hard drives in my RAID1. After adding the two new partitions the old ones are still showing up as removed while the new ones are only added as spare. I've had no luck removing the partitions marked as removed. Here's the RAID in…
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mdadm raid 1 grub only on sda

I just finished setting up a CentOS 6.3 64bit server with mdadm however a lightbulb went on and I realised grub would only be installed on the first drive which is about as much use and an ashtray on a motorbike. I had a look to confirm my…
Backtogeek
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RAID1: Which disk will be mirrored?

How does a RAID1 system determine which disk to use as the source and which disk to use as the destination when mirroring? Assume for instance the following scenario: A RAID1 array is created with two disks A and B. A is replaced by disk C, which is…
tmelen
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What would happen if I did a raid on a SSD and an HDD?

I am building another server (cheap) and would like to go with a 256GB SSD drive for my boot and data. This will be enough for my needs, but just having one SSD scares me for a couple of reasons. If I did a mirror raid with a SSD and an HDD, what…
Jason
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Linux Software RAID1: How to boot after (physically) removing /dev/sda? (LVM, mdadm, Grub2)

A server set up with Debian 6.0/squeeze. During the squeeze installation, I configured the two 500GB SATA disks (/dev/sda and /dev/sdb) as a RAID1 (managed with mdadm). The RAID keeps a 500 GB LVM volume group (vg0). In the volume group, there's a…
flight
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How does RAID detect a faulty HD?

I have been looking over Raid levels over the past 3 days. And have been weighing up the pro/cons of raid controllers hardware/software. I understand that RAID is not a backup solution and I'm perfectly fine with it, though one question still…
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