RAID1 or mirrored RAID uses two disk that have the same data.

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11answers
2k views

Is RAID5 more robust than RAID1

I am about to replace an old hardware RAID5 array with a Linux software RAID1 array. I was talking to a friend and he claimed that RAID5 was more robust than RAID1. His claim was that with RAID5, on ...
8
votes
1answer
29k views

mount: unknown filesystem type 'linux_raid_member'

I have Suse Linux 12.1 and i am trying to mount a single RAID 1 disk, to explore the files in it. However when mounting it: # mount /dev/sdc1 /mnt/test mount: unknown filesystem type ...
8
votes
2answers
865 views

How to attach an existing RAID1 to a fresh Linux system?

I have a RAID1 currently operating on a single hard drive (yes, the mirror is absent). Is it possible to reorganize my system using the following algorithm? I set up another single-disk RAID1 (onto ...
7
votes
1answer
3k views

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, ...
7
votes
1answer
561 views

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 ...
7
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2answers
259 views

Linux software raid fails to include one device for one RAID1 array

One of my four Linux software raid arrays drops one of its two devices when I reboot my system. The other three arrays work fine. I am running RAID1 on kernel version 2.6.32-5-amd64. Every time I ...
6
votes
3answers
625 views

Would unplugging a drive simulate a drive failure?

I just set up a RAID 1 array, 2 2tb drives mirrored. I am wondering what will happen if one were to fail. Would unplugging one of them be a valid test? I am using the Onboard controller of an asus ...
6
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2answers
339 views

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 ...
6
votes
1answer
542 views

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 ...
6
votes
2answers
1k views

How to make a Linux software RAID1 detect disc corruption?

This is one of the nightmare days: A virtualized server running on a Linux SW-RAID1 runs a VM that exhibits random segfaults in seemingly random codechunks. While debugging I find that a file gives ...
6
votes
1answer
7k views

Boot from software RAID 1 on Windows Server 2008 R2

I have a Windows Server 2008 R2 x64 system with a single hard drive, and I have a spare hard drive of same size/model that's not being used. I was thinking about dropping in the new drive and setting ...
6
votes
3answers
7k views

How to resize RAID1 array with mdadm?

I've running Ubuntu 11.04 (kernel 2.6.38-11). I replaced 2x160GB with 2x500GB drives. They are configured as RAID1. The partition tables show the right sizes. Here's sfdisk: # sfdisk -d /dev/sdb # ...
5
votes
2answers
1k views

NAS device claims drive in a RAID is degraded but S.M.A.R.T. says it is fine

I have a Synology DS213 with two 600GB drives in RAID 1. Last night the device reported that my second drive had become degraded and that I should replace it. When I ran a extensive S.M.A.R.T. test ...
5
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3answers
3k views

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 ...
5
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2answers
523 views

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 ...
4
votes
2answers
195 views

sda1 (?) raid failed on debian - what to do now?

ispconfig says that my server has raid problems. The server is not mine, it is rented from a hosting company. The OS installation was not my business: the hosting firm did it. cat /proc/mdstat ...
4
votes
3answers
256 views

File corruption when copying different file on raid 1

I have a RAID 1 configuration of 2 1TB drives on a Fedora 12 box. Most of what is stored there are video files that are numerical labeled. The problem I'm having is that I had one of the video files ...
4
votes
1answer
2k views

What's the difference between “mirror” and “raid1” in LVM?

On the lvconvert(8) man page it says: --type SegmentType Used to convert a logical volume to another segment type or to explicitly state the desired RAID1 segment type ("mirror" ...
4
votes
1answer
2k views

Ubuntu: Monitor hardware RAID and notify upon failure?

I am using the 3ware 9650SE-2LP Raid controller for a 2-drive RAID 1 setup in some new Ubuntu 10.04 x64 servers. Is there a way for the server to send me a notification when one of the drives fails? ...
4
votes
3answers
925 views

Write-read errors, Raid1 recovery?

This might sound stupid, but I'm supposed to ask any question here, as long as it is related. So here. I have RAID 1 on the server that is officially soon to be dead. After a chkdsk, the files are ...
4
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1answer
2k views

Very slow write performance on Debian 6.0 (AMD64) with DMCRYPT/LVM/RAID1

I'm seeing very strange performance characteristics on one of my servers. This server is running a simple two-disk software-RAID1 setup with LVM spanning /dev/md0. One of the logical volumes ...
4
votes
2answers
3k views

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 ...
4
votes
1answer
316 views

Sync SSD to spindle drive using RAID or DRBD

I'm setting up a server with and SSD as the primary drive, and would like to duplicate the data onto a cheaper drive as a block-level backup (à la RAID1). Since I don't want to hobble the performance ...
3
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4answers
3k views

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 ...
3
votes
1answer
607 views

Can you use drives while Raid 1 is rebuilding?

I am going to be rebuilding a raid 1 array. While the rebuild is happening can people still read/write to data in the array?
3
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4answers
357 views

Can I keep the data on my Raid 1 drives if I move them to a new Raid controller?

I have a couple of servers I'm about to decommission and they each have 2 raid 1 drives. I want to take these drives and put them in a DAS but I am told that I will lose the data because the raid ...
3
votes
2answers
344 views

RAID 1 Failover

Given two disks in a (hardware) RAID 1 configuration, what exactly happens to a production system when one drive fails? Is there any noticeable service interruption, or will the system continue ...
3
votes
2answers
553 views

Remove dead HD in Raid1?

I am on debian, raid1, one of the drives seems dead. root@rescue ~ # cat /proc/mdstat Personalities : [raid1] md1 : active raid1 sda2[0] 486279424 blocks [2/1] [U_] md0 : active raid1 sda1[0] ...
3
votes
2answers
2k views

RAID1: How do I “Fail” a drive that's marked as “removed”?

I have (had) a RAID 1 array (2 disk mirror) and one of the disks, sda, failed. So I've replaced the bad disk with a new one, but seem to be stuck on how to get the second drive back up and running as ...
3
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2answers
2k views

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. ...
3
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2answers
143 views

RAID1: One RAID per Partition or Partitions on RAID device?

What is better suited for a normal Server: several partitions, which are bundled as several RAID1 devices (/dev/md0, /dev/md1, ...) without any partitions, which are not mirrored. one big /dev/md0, ...
3
votes
3answers
1k views

RAID1 performance with madam

I am looking into performance issues we are having. We currently have a 4 drive RAID5 (3+1 fail over) and read performance sucks. Looking at RAID1 with 2 drives (maybe more, any benefit?) but from ...
3
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2answers
2k views

HP DL320e Gen8, 3TB drives, Windows Server 2012 R2 - HDD full capacity alocation difficulties during installation

One interesting task to do but not so easy as i thought. The server is HP DL320e gen8, The main difficulty is with partitioning the RAID1 (2x3TB HDDs) during the installation on 2 partitions (System ...
3
votes
2answers
700 views

Linux Software RAID1 Rebuild Completes, but after reboot, its degraded again

I have been beating my head with an issue here, and I'm now turning to the internet for help. I have a system running Mandrake Linux, with the following configuration: /dev/hda - This is a IDE ...
3
votes
2answers
1k views

Hot swapping under RAID 1

I have a server that supports hot swapping (such as HP ProLiant DL160 G6 with hot swap) (spec) and I configure it for RAID 1 mirroring across 2 disks. Say one of the raid'ed disks then fails. Can I ...
3
votes
1answer
1k views

Converting BTRFS filesystem to RAID1 fails with “Inappropriate ioctl for device”

I had a ~1.6TB BTRFS volume on a single partition, to which successfully I added another freshly created and formatted partition (on another device) of exact same size with the intent of mirroring ...
3
votes
2answers
455 views

From which plex am I booted from on raid?

I have a server with mirrored boot volume. It is software raid 1 in Windows Server 2008 R2. I do not have physical access to the server. I am looking for a way to check which disk is a boot drive. I ...
3
votes
2answers
159 views

RAID disk format / transferability between controllers

A couple of RAID questions. I think I know the answers, but just wanted to double-check since I am about to play will several years worth of personal data. Do I understand correctly that: If I have ...
3
votes
2answers
464 views

Can I 'un-raid' my raid 1 setup

My dell T7400 has two 300G 15k SAS drives in a raid 1 configuration. I'd like to instead have a 300G 'C" drive and a 300G 'D' drive. Is there anyway to remove one of the drives from the raid ...
3
votes
1answer
2k views

How do you set up RAID1 with both disks bootable on Debian/Ubuntu?

In Debian 6, new installation, what is the recommended way of setting up a software RAID1 array so that the system is bootable from both disks? I have heard that people that don't know what they are ...
3
votes
1answer
1k views

Linux RAID mdadm: what does 'Events' mean?

When I type mdadm --detail /dev/md0 I get a lots of useful information most of which I understand. However I also get a line that reads: Events : 0.710 Where the number varies. Naively, I ...
2
votes
2answers
2k views

CentOS - hardware raid 1 of two drives not being treated as single drive by fdisk

I am a bit new to hardware configuration in general, much less with linux, so please give me a little slack :) I have the following setup: 1 320GB Drive that contains the OS (centOS) and 2 250GB ...
2
votes
3answers
2k views

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 ...
2
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3answers
350 views

/boot on separate disk or on the raid array

I have 3 ssd disks (59 GB) each. I want to use them as sofware raid5 with fedora 15. I read that it is recommended to have /boot on a separate disk. 2 questions: 1) is it possible and advisable to ...
2
votes
2answers
491 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
1answer
767 views

RAID 1 configuration does not show after installation

I used the HP Smart Array Configuration utility to setup a RAID 1 array (hardware P400 controller) using four disks. I created 2 logical drives with physical hard drive 2 mirroring drive 1 (o/s ...
2
votes
4answers
481 views

how to know that RAID 1 is installed?

recently we have a server crash, so we decided to mount a RAID 1 in our server. so we asked to the hosting, they told us that was needed to reinstall all the system again. so we make it, and now i ...
2
votes
2answers
374 views

Motherboard fried on Windows RAID 1 System, do I have to reformat?

A faulty power supply fried my motherboard and I need some help. I had a spare motherboard lying around and hooked it up to one of the hard drives to see if I could just continue chugging along. ...
2
votes
3answers
2k views

Any disadvantages of using built-in software-RAID-1 on a Windows Server?

I have had some problems using hardware-RAID on a server. Now I'm planning to use the Windows Server built-in software-RAID-1 instead. The server will only be used for Business Administrations, so I ...
2
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3answers
1k views

Exchange 2007 | Mailbox DB Size 180GB

I have a Exchange 2007 SP1 server running on Windows 2008 6 HD Drives in a RAID-1 OS, DB, Logs on separate RAID-1 Disks Size of the Mailbox Database is 183GB and increasing We only have First ...