RAID - Redundant Array of Independent Disks. A Storage technology to provide redundancy and performance, to reduce I/O bottlenecks involved in using multiple disks for large storage.

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Two arrays have slightly different array size with same size disks/partitions, why?

I created a software RAID 5 array one year ago using mdadm v3.2.x which shipped from CentOS 6.3, after few months, I moved/assembled the array to/in Fedora 19 (now Fedora 20). It had three 3TB disks ...
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How is default readahead value determined

I have two different devices running XFS and the default readahead value set differs between the two disks. Why is that ? How is the default size computed ? Is it device dependent ? I might also add ...
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18 views

Change Initramfs script

I made RAID 0 by mdadm'ing partition located on dmraid VIA VT6421 and Western Digital hdd. Installed Ubuntu on that RAID. Now, when I boot, I get (initramfs) ash prompt. There, I have to write mdadm ...
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40 views

Why does fstrim trim all of the free space on my mdraid mirror after a reboot? [duplicate]

I have a server with 2 SSDs: Model Family: Intel 520 Series SSDs Device Model: INTEL SSDSC2BW240A3F Firmware Version: 400i User Capacity: 240,057,409,536 bytes [240 GB] Sector Size: ...
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61 views

Terrible performance on linux mint 16

I am having difficulty with getting linux mint to cooperate with my desktop. Specs: Mobo: Maximux IV Extreme-z CPU: i7 2600k GPU: 2x R9 290x Storage: (240GB) 2x OCZ Vertex 3 on RAID0 (Currently ...
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3answers
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Recovering data from a failing RAID 5 setup

I have a four disk RAID 5 array that is in the process of failing hard. One disk is completely dead and smartctl is telling me that a second disk is failing. All the data on the RAID is backed up, ...
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1answer
314 views

cleaning /dev/md0 filesystem ( raid)

I have a CentOS server using raid. The /proc/partitions contains: major minor #blocks name 8 0 976762584 sda 8 1 104391 sda1 8 2 921600855 sda2 8 3 55054755 ...
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Cannot get status of “Adaptec AAC-RAID (Rocket) (rev 02)” HW RAID card

SERVER:~ # lspci | grep -i raid 0000:04:00.0 RAID bus controller: Adaptec AAC-RAID (Rocket) (rev 02) SERVER:~ # arcconf getconfig 1 pd and after the arcconf, the command just hangs.. the server ...
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1answer
192 views

How to rebuild a two drive raid 1 array on Linux?

I need to rebuild a two drive (160x2) raid 1 (mirror) array. It was an Intel raid from a 7 year old Dell computer (Windows). Both drives are assumed to be functioning. The raid was created with an ...
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37 views

Possible problems in moving linux disks from one hardware to another

I currently have a server collocated in a datacenter. The hardware is a HP dual quad core xeon with 16 Gb DDR2 and 2 1Gb disks in raid1. I want to order another similar server to have as a ...
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139 views

RAID setups questions

I have a RAID setup questions My mobo supports hardware RAID, my question is, should I use the board's RAID system or freeNAS/Ubuntu's software RAID system? I realize performance is better with h/w, ...
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1answer
73 views

Run smartctl on all disks of a server [Solved]

My question is a quite simple , I want to run the command smartctl -i -A on all disks that the server have. Think that I've too much server with different number of disks and RAID Controllers, then I ...
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2answers
353 views

Can I mount a microsoft mirrored dynamic disk?

I'm testing out sw raid in windows 7, but I almost always use linux and I would like to know if it's possible to mount such a mirrored dynamic disk. I can already mount each members separatly but ...
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1answer
116 views

How to setup a RAID system using USB sticks as storage media

I want to create an inexpensive self-hosted private git server with redundant storage. To that end I have bought a Raspberry Pi and configured both git and ssh on the Pi. I can access the Pi both from ...
2
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1answer
92 views

Proper way to setup RAID in linux

I have installed Debian 7.4 on a server, and through the installer I setup both RAID and LVM for the drive that the OS is installed on. However, now I want to add two 4TB drives in a RAID-1 array to ...
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1answer
30 views

understanding the “chunk size” in context of RAID

Am I correct that chunk size in context of RAID is essentially the same thing as cluster in file-system context? In other words, chunk size is the smallest unit of data which can be written to a ...
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2answers
80 views

Grow LVM RAID10?

RHEL LVM has supported RAID4/5/6 as of 6.3 and RAID10 as of 6.4. It's well-known that mdadm won't let you --grow raid10, my question is whether this is a limitation of LVM RAID10 too? If it is ...
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1answer
41 views

Debian Squeeze RAID 5 Install?

I have a box with four Hard Drives on it. I am going to install Debian Squeeze (I know it's old... I have to) on it. I want to be able to treat the the four Hard Drives as a single Harddrive. Durringt ...
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1answer
94 views

Proxmox Master Node crashes

I've inadvertently discovered a Proxmox bug. I run a personal cluster of 4 nodes (a technology lab for giggles and gags). Each node has a Dell Perc 5i and 4 HDDs in RAID 10. The standard Proxmox ...
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45 views

mdadm large memory consumption [closed]

I am building a RAID 6 with mdadm (8 WD Red 3 Tb) on Ubuntu 13.10x64 server with ext4 filesystem. When I download torrent on the array, server RAM is filled for maximum cap (8 Gb) memory is free when ...
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59 views

Fdisk cannot read size of this disk is 4.0 TB under RAID-0 enviroment

I have server from OVH data center , I have Two SATA Hard Disk Drive , each Disk Size 2.0 T.B , I have RAID controller card but I convert the RAID-1 to RAID-0 through OVH Rescue mode and here is the ...
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1answer
103 views

mdadm - RAID5 array size vs. actual disk size mismatch

I have 4x 3TB WD RED disks that are in mdadm RAID5, which should total an array size of 9TB usable space, however I only have 6TB. I have confirmed all disks are in the array, the only strange thing ...
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344 views

bootloader configuration with GPT, RAID1, and LVM

Using the GUID Partition Table and RAID 1, the bootloader (syslinux or GRUB) is not able to boot into the machine, which was installed with Arch Linux. First off, there are two drives identical ...
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Tuning a CentOS VM running on an MDRAID-based XenServer storage repository

I've run out of ideas for tuning disk write speeds on a handful of CentOS VMs running on a lab XenServer 6.2 host. Running under the free license (so vendor support not a concern), the lab host is a ...
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509 views

bit rot detection and correction with mdadm

I'm about to re-organise all my HDDs in my linux box nas and would like to use mdadm raid for data protection and its flexibility for reshaping the arrays. However, before I use mdadm for this I'd ...
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113 views

Why is my ext4 filesystem recognizable only on the machine it was formatted on?

Xubuntu liveCD 11.04 running on "bad machine" with mdadm RAID1 array with an unrecognizable ext4 filesystem: To rescue some files, I installed a new hard drive and formatted it to ext4. I copied ...
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1answer
157 views

Mount an existing RAID 1 Logical Volume after OS upgrade

I just upgraded from Ubuntu 10.04 to Mint 16. The installer did not detect my existing RAID 1 array, and I can't access it anymore. My drives are: SDA - First RAID Disk SDB - Second RAID Disk SDC - ...
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How to migrate the content of one disk on a Raid5?

I have one 1.5Tb HDD with Debian Wheezy. I have also four 2Tb empty HDDs. I want to configure the four 2Tb disks in Raid5 and install LVM. Then migrate the content of the 1.5Tb disk on the Raid5. ...
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1answer
53 views

raid1: how to synchronize harddisks (Debian 6)

My system is Linux/Debian 6, using GPT (GUID Partition Table). If I run the command cat /proc/mdstat I see the following situation: Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] ...
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1answer
117 views

Does CentOS 5.9 need Grub to run on hardware RAID?

I'm doing a fresh install of CentOS 5.9 x64 on a server with 8 disks in RAID5. At some point during the install, it gave me the option of configuring Grub, or not bothering. I chose not to bother, ...
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installing grub 2 on mdadm, which device?

when installing grub(2) to mdadm devices are you supposed to install it to /dev/sdX or /dev/mdX?
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Install Kali Linux on RAID0 (as dual boot Windows 7 & Kali)

I’m currently trying to install Kali Linux on my laptop as described here. The problem is I’ve a laptop (MSI GT70) with a Raid 0 (2x 500Gb) and Windows 7 installed on it. At the point where I’ve to ...
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913 views

Strange error message during CentOS 6.5 installation regarding disk containing BIOS RAID metadata?

While attempting to use an old 40GB HDD to setup a kind of junky though usable Athon 1GHz system I ran into the following error during the HDD identification/partitioning phase of the installation: ...
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1answer
203 views

How to remove disk from RAID1 without knowing the /dev/XXX name?

BEFORE: SERVER:~ # mdadm --detail /dev/md5 /dev/md5: Version : 00.90.00 Creation Time : Fri Mar 18 14:53:33 2011 Raid Level : raid1 Array Size : 67103360 (63.99 GiB 68.71 GB) ...
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2answers
314 views

Best way to create RAID on an existing system drive

I want to add another disk as RAID 1 to test my database performance. I am trying to not re-do the whole system, is it possible? Currently I have a single 1TB HDD with one 100GB system partition (and ...
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3answers
158 views

Software RAID 1 with dissimilar size and performance drives

Background I was experimenting with a home server setup in a small box I had that was supposed to be a media centre but never found much use. I installed CentOS 6.5 in a software RAID1 configuration ...
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178 views

Is a ZFS storage array portable across operating systems & CPU Architectures?

I know that ZFS is available on variety of operating systems Solaris, Illumos, Linux, BSD etc. Suppose I have a bunch of disks that are part of ZFS raid file system that was created on Linux, could ...
3
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1answer
1k views

New md array is auto-read-only and has resync=PENDING

I've created a new md array with the following command: mdadm --create /dev/md1 -l 1 -n 2 /dev/sd[ed]1 But now /proc/mdstat shows the array as "auto-read-only" with resync=PENDING: ~ # cat ...
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What happens if I delete dmraid?

I am new to Linux and am trying to install Ubuntu 12.04.3 LTS from a live-USB and have it run alongside my Windows 7 installation. On the installation screen for Ubuntu, at the partition page, I get ...
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1answer
29 views

RAID configuration file not present

I am trying to configure RAID disks in my SUSE machine. I have 2 disks currently. I am trying to configure them as RAID using the below command. mdadm --create --verbose /dev/md0 --level=stripe ...
2
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1answer
50 views

RAID mount not happening automatically

I've configured RAID array in my SUSE machine. Everything works just fine as expected. However, I need to mount the RAID array automatically when I boot my system. For this I added the mount point in ...
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1answer
45 views

raid array not mounted

I have configured RAID array in my SUSE machine using mdadm command. The /etc/mdadm.conf is fine and cat /proc/mdstat shows up the array and it is also fine. However, if I run the df -h command, it is ...
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1answer
146 views

RAID configuration disappears after reboot

I am using SUSE to install Hana in my system. I have 2 298 GB HDDs which I am going to configure as RAID 0. I am using mdadm to create a RAID array. I use the below command to create the RAID array. ...
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1answer
44 views

Linux installation in RAID

I am a fairly new systems administrator and I have to configure the RAID on a Linux machine. From my understanding so far, RAID is an array of multiple disks. I have some questions though. Question ...
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1answer
152 views

mdadm; previously working; after “failure”, cannot join array due to disk size

Abstract I had a functional Raid 5 array, I rebooted the box, and then mdadm couldn't re-assamble one part. Seeing that it was only one part, I thought it would be easy to just re-sync. But that ...
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2answers
109 views

Are disks interchangeable in a mirrored RAID setup?

It is often written that disks in a mirrored RAID (like RAID 1) are an exact mirror copy one of another. So can I turn the machine off and simply swap the two harddisks cables? And if one of the two ...
3
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1answer
723 views

recovery data from RAID and disk failure (Linux)

Some background A friend of mine was using in his office a NAS Buffalo-LS-WVL with two disks of 1TB each. It seems that the two disks were mounted as raid 1, but, as you will read, probably they have ...
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37 views

Restored VG has shifted volumes

I'm recovering a PV on a mdadm RAID 1 with a single VG containing several LVs. The underlying devices have several bad sectors (one just a few, the other really much) and a silly typo made it ...
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56 views

error running raidctl on Solaris 10

I am trying set up a disk mirror on a Solaris 10 system. The two disks are identically formatted and not mounted. Neither is a boot disk. I ran the following: # raidctl -c c1t2d0 c1t3d0 ...
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RAID 5 with 4 disks fails to operate with one failed disk?

I found a question about mdadm spare disks which almost answers my question, but it isn't clear to me what is happening. We have a RAID5 set up with 4 disks - and all are labeled in normal operation ...