Multiple Device driver aka Linux Software RAID

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MD RAID sector repair

This article states that RAID controllers are smart about unrecoverable read errors, and try to rewrite such sectors with the redundancy of the component drives. If the sector is bad, the disk's ...
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1answer
24 views

Force server to use all resources for resync

I need to resync my RAID and noticed that it isn't a big consumer. I have booted my system with the Rescue CD and started the resync. Looking at top it seems that the processes doesn't take much ...
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Software-RAID with ext4 but without 64bit support

last year I set up a Software-RAID5 with 5x3TB yielding 12TB of usable capacity. Just today, needing more storage, I have finished growing the RAID to two more 3TB disks: Personalities : [linear] ...
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Raid1+0: create stripe over two /dev/mdx on partition or not?

Given that I haven't found a way to define how a Raid10 is created with mdadm, i went the Raid1+0 solution. How to display/define Mirror/Stripping pairs with mdadm mdadm --create /dev/md0 --level=1 ...
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1answer
73 views

How to display/define Mirror/Stripping pairs with mdadm

I want to make a standard linux software Raid10 over 4 HDD. The server has 4HDDs, 2 pairs from different vendors in order to avoid batch problems. I want to have the mirror over two different ...
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1answer
56 views

md raid1 reading from one disk only

I have two identical HDD in a linux software raid 1. I observed a mostly reading load on this raid device, with the process showing mostly iowait. iotop shows about 75% disk utilisation overall. If I ...
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1answer
78 views

System wont boot from degraded RAID6

I have a Debian Wheezy with 3 Partitions as RAID6. MD0 is for Root and OS, MD1 is for SWAP and MD2 for Files. While copy files to MD2 the system reports kernel panic and halts. I have had shutdown on ...
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57 views

reusing existing raids on preseeded instalation

I'm trying to automate reinstall process of existing ubuntu installation. partition layout : md0( raid1, /dev/sda1#/dev/sdb1 ) - swap (2G) md1( raid1, /dev/sda2#/dev/sdb2 ) - / (20G) md2( raid1, ...
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Linux MD Raid same device detection

Linux md raid driver delays recovery/verification of multiple devices if they share the same parent device. We have setup where disks are pationed via device mapper, they use bcache, etc.. and ...
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139 views

SSD+MDRAID+LVM+KVM results in lower performance than expected

We use kvm for virtualization, the disk images are stored as logical volumes. The logical volumes are stored on a bunch of software-RAID1 (mdadm) arrays composed of Intel DCS3500 SSDs (each array is a ...
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1answer
285 views

Boot failure with root on MD (RAID1) + LVM: udev event timing

A fresh install of Ubuntu Server 13.10 (x64) is having problems booting from its root volume located in md+lvm. I've kludged a solution for now, but I'd like to understand more about what's going on ...
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Recommended solution to join partitions (disks) into single partition [closed]

I have 4 hard disks (1 Tb each) on server. It's debian wheezy, amd64. Disks 2,3 and 4 are not partitioned yet. I have to join them into single partition, it must be single filesystem/mountpoint for ...
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1answer
393 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
372 views

Remove a duplicate lvm physical volume uuid?

After upgrading a rhel 5 server today I rebooted to the new kernel: curr=2.6.18-371.el5PAE prev=2.6.18-348.18.1.el5PAE. In the boot sequence I saw a message indicating Logical Volume Management was ...
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2answers
402 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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1answer
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Is there anything I can do with a software RAID 1 on linux to workaround temporary 'bad' sectors?

Basically I have two identical hard disks that are in perfect working order, they just don't have the vibration tolerance they need for the environment they are in. (I am making an educated guess that ...
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1answer
171 views

HDD compatibility to rebuild for RAID

Last year we build a RAID 1 with Western Digital 2 TB drive model number WD20EARS. Unfortunately one of the drives failed. We are unable to find any new drives of the same model number. What do we do? ...
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1answer
94 views

Fresh setup: how to tell mdadm not to bother synchronizing the _data_? Or does it have to?

Two questions: how, if at all, can I tell mdadm that the freshly created array needs no synchronizing because there is no data on it? I.e. basically force it into a state where it assumes that the ...
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2answers
1k views

mdadm stalls rebuilding a RAID5 array at 99.9%

I recently installed three new disks in my QNAP TS-412 NAS. These three new disks should be combined with the already present disk into a 4 disk RAID5 array, so I started the migration process. ...
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2answers
142 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, ...
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1answer
113 views

Reshape linux md raid5 that is already being reshaped?

I just converted my RAID1 array to a RAID5 array and added a third disk to it. I'd like to add a fourth disk without waiting fourteen hours for the first reshape to complete. I just did this: mdadm ...
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2answers
577 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 ...
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2answers
358 views

Headless server with an mdraid array won't boot

I'm in a bit of a pickle. I have a headless server (Acer EasyStore) running Ubuntu 12.04.1, which, after an update, now refuses to boot. It has four disks, one of which holds the OS in a partition and ...
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What should I know before I set up RAID 6 on Linux?

I just ordered five 1TB drives to install as a RAID 6 array in a Linux server (keeping the existing 1TB drive as a boot disk). I want to use Linux MD for RAID rather than a RAID card, to avoid ...
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2answers
5k views

How to stop a Linux LVM volume group?

I am currently dealing with a multiple disk failure on a Linux LVM Volume Group that is backed up by a RAID-5 md device. One disk has been taken out completely and another one is showing a limited ...
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1answer
636 views

Upgrade grub to grub2 with MD RAID

I have a machine running Debian 6. Because of some recent changes, I tried upgrading to Grub2 (yes, grub legacy was installed by default). Everything went well (chainloading, reboot) until I started ...
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1answer
885 views

What effect does RAID stripe size have on read-ahead settings?

I'm trying to figure out the correct read-ahead values to set on a RAID10 array, and I'm wondering if the RAID stripe size should factor into my considerations. I've heard conflicting information ...
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2answers
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Readahead Settings for LVM, Device-Mapper, Software Raid and Block Devices - what wins?

I've been trying to find a straight answer on this one, and it has proved elusive. This question and its answer is close, but does not really give me the specifics I would like. Let's start with ...
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3answers
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Deciphering continuing mpt2sas syslog messages

Summary I have been getting these cryptic messages in syslog since I installed some new hardware and I can't figure out what the problem is, if it's serious, or what to do about it. They're from the ...
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3answers
290 views

Can I split one RAID1 partition in two?

I have a linux box with CentOS 6.2 and a RAID1 (2x 2Tb) configuration: /dev/md1 -> / (10G) /dev/md2 -> /home (1.9T) I want to split the md2 in two different partitions, so I can get the ...
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1answer
130 views

VERY peculiar permission masks, UIDs, GIDs and file names in Linux

I've just booted to find my software RAID 5 in Ubuntu not mounting. When trying to mount it gave me an NFS error (which was confusing). I ran fsck on /dev/md0 and my screen scrolled with fixes for ...
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994 views

Can't mount logical volume, RAID/MD/LVM problems

I have a file server with 48 2TB HDDs split across 2x 3ware 9650SE-24M8 RAID cards. Both cards have 24 drives in RAID 1+0. MD softraid is setup in raid 0 with the two RAID 1+0s making RAID 100. LVM2 ...
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1answer
739 views

Backup data from RAID 1 disk out of its server

I'm facing with a pretty easy problem in my opinion. I've extracted a working disk from a RAID1 and I'm looking to copy only data (FS and RAID configuration doesn't matter) into another location ...
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MD Raid can't be assembled

I was running a Raid5 with 3 disks at on my homeserver. But had some problems with the back-plane for the disks. The disks weren't detected reliable. So I replaced the back plane and the disks are now ...
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2answers
474 views

Linux Software RAID recovery

I am seeing a discrepancy between the output of mdadm --detail and mdadm --examine, and I don't understand why. This output mdadm --detail /dev/md2 /dev/md2: Version : 0.90 Creation ...
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2answers
893 views

Move an existing RAID 5 array from Ubuntu to Gentoo

I have a 64-bit Ubuntu machine with a 4-disk RAID 5 using software raid (md). I've been able to boot an Ubuntu LiveCD and recognize the array with a simple mdadm -A /dev/md0. It was easy to mount ...
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2answers
2k views

Why does RAID5 with an odd number of data disks have poor write performance

According to the comments on my other question, it's more than possible that the reason my MD RAID array is performing poorly is because my RAID5 array has 5 data disks. I've tried searching for ...
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500 views

Rebuilt md raid 6 array now showing xfs errors. How bad is it?

We had a storage server with performance starting to be poor. When I installed Linux's smartutils, it found Device: /dev/sdm, 2 Offline uncorrectable sectors Since this was a rather large raid6 ...
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3answers
683 views

Linux boot: md raid FS not ready (sometimes)

Using Ubuntu 11.04 (latest patched) I have 5 RAID-1 file systems that are automatically assembled during the boot process (Note: none of the system FS /, /usr... are raid, only user FSes). Once in ...
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2answers
413 views

how to get block sizes larger than 4k in reads from an md raid1 volume

I wanted to setup a raid01 configuration (a raid1 composed of two raid0s) with one of the raid0 volumes having the write-mostly state set so all reads would go to the other (i.e. one is disk, the ...
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1answer
2k views

Linux software RAID that uses system RAM for write cache

Is it possible to configure software RAID 5 on linux that uses system RAM for write cache? I have a file server with 8GB of RAM ... would be really cool if I could dedicate 4GB to write cache. If ...
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1answer
161 views

Erratic write patterns with linux md RAID1

I'm experiencing strange write performance patterns on a RAID1 array of SATA disks. My kernel is vanilla 2.6.37 and my server has 32G RAM. I'm copying a 32G file from an XFS filesystem on a SAS drive ...
2
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1answer
628 views

MD RAID 1 with external bitmap doesn't fully resync

I have an interesting configuration: dual boot system with a RAID 1 that needs to be visible in both Windows and Linux. The Windows install is Win 7 Enterprise, and the Linux install is Kubuntu 10.04. ...
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562 views

Combining Dell MD SAN with HP MSA60 DSA?

Would it be possible to combine a Dell MD SAN with a HP MSA60 DSA, or am I forced to use it with other HP StorageWorks products? The MSA60 spec reads: Storage expansion: Supports 1+3 cascading off ...