RAID solution handled by the operating system.

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CentOS System Recovery : Overwritten RAID Superblock and porting to new hardware

I have a failed system running on CentOS 6 and would like to attempt recovery of system. One problem it has is the mdadm superblock appears to have some issues, it has all sorts of inconsistent ...
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1answer
67 views

mdadm - diffference between metadata version

Can anyone tell the difference between all the metadata versions for mdadm? When I try the command mdadm --examine /dev/sda1, I can't seem to find preferred superblocks on version 1.2. Is there a ...
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174 views

Software RAID: file system becomes read-only, mdadm fails with SEGFAULT

I have software RAID1 on Ubuntu 10.10 (Linux ubuntu 2.6.35-32-generic-pae). It is dedicated server I control via SSH. Yesterday datacenter people changed one HDD which was crushed. I did not run ...
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210 views

RAID6 Ubuntu rebuild - how to calculate best parameters for fastest rebuild

I am doing a resync on a RAID6 array and I am looking at some 2 days to complete. I looked here for hints on how to speed it up, but I have, instead, managed to slow it down! HW details are: 10x 4TB ...
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3answers
145 views

awk ignores the record separator I set for the first record

I am trying to change the record separator but awk does not use the record separator I set until the second record and beyond. I get output like this: ARRAY /dev/md4 level=raid1 num-devices=2 ...
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2answers
1k views

Linux software-RAID4/RAID5 and CPU usage

In case of RAID4 or RAID5, for each stripe of data bits, a parity bit is stored. For example if I write 0 to drive A and 1 to drive B, then parity bit 1 is stored to drive C. Isn't this a huge load to ...
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1answer
59 views

Is it possible to write into RAID chunk multiple times?

As far as I know, (most) file-systems do not support one to write into file-system cluster multiple times. In other words, cluster is the smallest unit in file-system and even if a single bit of ...
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1k views

calculating optimal chunk size for Linux software-RAID

Am I correct that optimal chunk size is average file read/written to disk divided by number of block devices in RAID array storing the data? For example if the average file size is 1024KiB and I have ...
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0answers
86 views

mke2fs.ext3 stripe-width option missing

I'm trying to set up an ext3 filesystem on a RAID 6 array (with 6 disks) on XenServer 6.2 linux. All the help I can find tells me to use the -E stride=xx,stripe-width=xx options. However my version (...
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1answer
576 views

Linux; Set RAID5 chunk size to 4kB to match FS block size and physical disk sector size

There are many discussions and websites that explain the process of setting up a Linux software RAID with mdadm with the chunk size of a new RAID as 128kBs or 512Kbs. Serverfault is no exception. I ...
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1answer
172 views

Recovering Linux soft raid 5, disk stays as spare

I got disk failure on my Centos Linux soft raid 5 array (mdadm). I replaced one of the disk and started to rebuild the array. Next time I checked the status, the rebuild was failed. This is the ...
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242 views

Why was the replacement drive for failed drive in RAID 1 (linux software raid) was added as a spare?

I have a two drive linux software raid 1 for a server. There are two raid devices. (Boot (md0) & OS (md1)) Last week one of the drives failed so i ordered a new one. Today i shutdown the server, ...
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1answer
619 views

Linux Server OS on LVM on Software RAID: Best Practices and Considerations

I am preparing for a minimal Ubuntu Server 12.04 LTS that will simply run libvirt/KVM to host a handful of Ubuntu Server 12.04 LTS guests. On my KVM host I created a RAID 1 comprised of two physical ...
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2answers
789 views

Sanity check on 40TB server configuration

I've got 40 years in computing, but I've never had to build a server quite like this one, so this might be a n00b question. I have a client that is going to offer ultra-high def music files for ...
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4answers
501 views

Best Linux Partitioning for Multiple Resizeable HDD

My ISP has a machine with 6 HDDs (3TB+3TB+3TB+2TB+2TB+1TB) which we want to turn into a FTP/Download server for local users. I am planning to install CentOS 6.5 on one 2TB, rest of all space shall ...
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0answers
8k 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 ...
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166 views

mdadm array fails to start at boot, bad superblock on component drive

At boot my mdadm raid5 array fails to start, saying that one of my disks (sdi) has a bad superblock. However, once I log in, I can start the array no problem with mdadm --assemble /dev/md0 /dev/sd[...
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1answer
843 views

Mixing SATA & SAS drives on same server for software raid

Is it possible to mix SATA and SAS drives on the same controller? These are intended to be used these in server 2012 R2 software raid, obviously not mixed in the same array but maybe on the same ...
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1answer
309 views

raid 1 always degraded after pushing reset [closed]

I have Marvell hardware raid 1. After pushing reset or any other incorrect shutdown raid is degraded. Is it possible to create hardware raid 1 on other chips(intel chipset for example) for example ...
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3answers
520 views

mdadm raid6 built, but no mounting or fsck

I had some problems with my RAID 6 drive on mdadm recently. No LVM in between. Two drives died, and were pulled out while the machine was powered down. Now, I boot up the system, and cannot mount the ...
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3answers
5k views

Turn off RAID on HP DL380? [duplicate]

Can anyone tell me how I can turn RAID off on a DL380-G5. I just want the disks connected directly without any RAID as I want to use this to test Microsoft's software RAID. Can't seem to find ...
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3answers
304 views

Linux MD RAID resilience in situations with unpredictable power

If you were given a situation where you MUST use RAID for reasons outside of your control and the server with the RAID may not be on a battery backup and the building is prone to power loss, what are ...
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1answer
221 views

retrieve software RAID information using WMI [duplicate]

I need to get software RAID configuration info from a remote windows server (2003, 2008, 2012) on a local linux system. I have searched and searched, but have been unsuccessful at finding a solution, ...
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1answer
93 views

What are the pros/cons of software raid made up disk connected over SATA and others over USB? [closed]

I would like to use RAID1 with 1 SATA disk and 2 USB disks PS: This is an ARM board (cubietruck) with only 1 SATA port and 2 USB ports. PS2: The OS boots from a SD card :) PS3: The setup does not ...
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1answer
49 views

Mirroring System Drive On Server 2008

I have server 2008 installed on a hard drive that disc management calls a "basic volume." On this hard drive I have partitions configured for certain sets of data. I want to buy a second hard drive ...
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1answer
253 views

RAID-5 array being split on reboot (ubuntu)

I've set up a RAID-5 array on Ubuntu 13.04 (kernel 3.8.0-27-generic) using mdadm - v3.2.5 - 18th May 2012. It appears to work fine and be in high spirits: $ cat /proc/mdstat Personalities : [linear]...
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596 views

Restore LVM if VG is not consistent (XenServer 5.6.1)

i have a VG that uses the PVs /dev/md1 and /dev/md2. Now one hdd failed in /dev/md1: [root@xenserver1 ~]# cat /proc/mdstat Personalities : [raid1] md1 : active raid1 sda3[0] 382320128 blocks [2/...
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1answer
734 views

Can I use a RAID card with chipset SIL3124 with no driver?

I have a software RAID card with a SIL3124 chipset. (This one). As you configure the RAID via BIOS, is it possible to use this card with 3 disks (RAID 5) with any OS without installing any driver on ...
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0answers
79 views

What is the issue with the boot setup on this raid array?

After a secure erase of /dev/sda (Samsung 840 Pro) I had to setup grub on /dev/sda2 (for some unknown reason the /boot partition is the second one). So I ran something like this: grub<br> root(...
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3k views

KVM LVM-based guest… kernel: Buffer I/O error on device. Failing drive?

Currently setting up a small KVM host to run a few VMs for a small business. The server has 2 drives in software md RAID 1, then I have it set as a PV in an LVM setup. Guests and hosts are all CentOS ...
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1answer
42 views

mdadm grow operation giving nonstop libata errors

Running Debian 7, mdadm 3.2.5. I issued a command to grow a 5 disk, 3 spare raid 5 array to an 8 disk, 0 spare raid 6 array: mdadm --grow /dev/md0 --level=6 --raid-devices=8 --backup-file=/root/...
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2answers
69 views

hba for software raid

In a software raid environment, is HBA failure the same as a hardware RAID controller failure? Do you still have to find the same model HBA to put into a different server in order for the drives to ...
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1answer
1k views

RAID1 on existing CentOS6 Install

I have two 500GB hard drives in my server. Currently, there is no RAID configured, but CentOS6 is installed (as a bare install for now). Is it possible to set up a software RAID-1 so that both drives ...
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2answers
691 views

Path of md device wrong after reboot

I have to set up a software raid (level1) on a Ubuntu server 12.04. It should serve files in the network via Samba. The server has the following disks: 250gb Sata hdd (Ubuntu is installed on that ...
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2answers
253 views

Linux: How to restore data from failed disk from software raid

I have a disk failure in software RAID (1) and marked a broken disk as fault (mdadm --manage /dev/md0 --fail /dev/sda1). Unfortunately I destroyed data on the second disk after that. Is it possible to ...
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1answer
266 views

ZRAID1 pool size bigger than expected

I have 3x 4TB drives for a ZRAID1 config (single parity drive) After running zpool create data zraid1 sdb sdc sdd I have a volume that's 10.9T in size, which is what I would expect from a stripe ...
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1answer
537 views

Recoving from a software RAID 5 disk failure

I'm putting together a cheap NAS box and I've read some articles about raid5 not being as robust as I'd imagined. I wanted to get some answers to the following questions before I proceed. I'm ...
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1answer
702 views

Various problems with software raid1 array built with Samsung 840 Pro SSDs

I am bringing to ServerFault a problem that is tormenting me for 6+ months. I have a CentOS 6 (64bit) server with an md software raid-1 array with 2 x Samsung 840 Pro SSDs (512GB). Problems: ...
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2answers
85 views

What is the correct way to create new raid5 in Linux?

I added some new disks, and tried to create new array, using: mdadm --create /dev/md/2 --level=5 -x 0 --raid-devices=4/dev/sd{a,b,c,g}2 It creates the array, but after reboot - it's gone. What ...
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1answer
2k views

Server 2012 (R2) - mirroring the boot drive… what is the state?

I struggle to find modern documentation here. So far we have been booting our servers from the main RAID controllers. Worked nice, but not we get the first of a new generation that hs in the back 2 ...
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1answer
267 views

Raid0 assemble disk again?

Our server recently suffered a disk failure, so our hosting provider put a new Disk in with CentOS so we can login and see if we can recover the data. We had 2 x 120 GB SSD drives in software RAID0 ...
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1answer
301 views

Sharing an EC2/EBS RAID10 Array using NFS

I created a 10 disks RAID10 using EBS on AWS EC2 using mdadm on a ubuntu 12.04.2 LTS instance. Let's call this instance A. It works fine and I can create files and folders perfectly in the volume. I ...
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3answers
1k views

Slow software raid with SSDs

We have moved a web application with an Oracle database to a new server because the old one was dying. The old server had two mirrored hard discs plus a separate non-mirrored SSD for the Oracle ...
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2answers
549 views

Convert Raid 1 to Raid 10 with no new disks

I just got a new remote root-access server with 2 1TB disks in a Raid 1 configuration, running Debian (squeeze). Before installing my stuff on it, I'd like to switch to Raid 10 if I can. All the ...
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1answer
581 views

How to increase disk write-speed for SSD RAID10 array?

I've had no luck searching how to setup writeback cache on a RAID10 setup using mdadm software RAID. I'm trying to set this up for a 4x256Gb Samsung 830 SSD setup which only has 400Mb/s write speed... ...
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1answer
132 views

Does the built-in CentOS software RAID distribute writes?

Will I see a write performance increase going from single disk to CentOS Software RAID10? Any industry estimates on the % increase?
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1answer
3k views

How to get email alert if one of raid 1 disks fails?

I need to know how can I get email alert if one of raid 1 disks fail to work/crashes. I have CentOS 6.4 64bits, software raid. I did some mistake folowing this tutorial, because it was a bottom note ...
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1answer
176 views

Installing Raid 1 on Ubuntu 13.04

I am trying to install raid 1 on my new ubuntu server using software raid. My drives are 2 x 3TB I have set the format of the drives to gpt. Created 3 partitions (1mb - grub) (2gb swap) and the ...
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2answers
6k views

Dell T110 II Server 2008 R2 Installation

I have a Dell T110 II with 2 1TB drives in raid 1 using the S100 on board raid. When I load Server 2008 R2 it says, "No device drivers were found. Make sure that the installation media contains the ...
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1answer
105 views

How to mount Soft RAID in centOS

My dedicated server crashes. I've rebooted it in rescue mode and want to mount to see the log and/or fix the boot file. I've CentOS and soft RAID. How do I mount soft RAID? Following are the details: ...