Multiple Device driver aka Linux Software RAID

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SSD fstrim on CentOS 6.x with software raid5

I have some CentOS 6.x servers. They have software raid1 and fstrim works well there. On one of the servers, I decided to do software raid5 and ext4. I can mount it with discard and there is no error ...
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34 views

dracut-pre-trigger rd.md=0 removing md raid activation boot fails

The system is Fedora 22, recently upgraded from Fedora 21. The remaining kernel from Fedora 21 boots. The two kernels installed after the upgrade fail to boot. The system is an Intel S-5000 PAL with ...
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“personality does not support diskops!” when trying to add a drive to a mdadm raid array

I have a linux (3.19) server which uses software raid (mdadm v3.2.5) and there is a raid0 device (/dev/md2) set up, which currently has only /dev/sdb3. I want to add the unused disk /dev/sda3 to this ...
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Can I convert a single-disk system to software RAID1 without double-copying?

I have read this question: Can I create a "soft" RAID1 array without nuking data? as well as many other tutorials that layout this general process: Create degraded RAID1 array on new drive ...
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30 views

md raid10: how to make sure that replicated data is stored in right place?

When creating classic mirrored raids, it's usual to locate copies of data on disks of different kinds. In this case you would use a mix of disks of different series and manufacturers. That reduces the ...
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268 views

Debian server has degraded mdadm array on every boot

I have a Debian server with MD raid (2 actives, one spare): Personalities : [raid1] md1 : active raid1 sdc2[0] sdb2[1] sda2[2](S) 1068224 blocks [2/2] [UU] md0 : active raid1 sdc1[2](S) ...
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284 views

recover highly degraded raid array

I have a Linux RAID6 array (mdadm) composed of 8 disks. 2 disks failed. I replaced them, now I have 2 new empty disks. I would like to rebuild the raid but when I start a raid rebuild, the rebuild ...
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on fedora 20 is it possible to migrate an active sd device into a mirrored group

On my system (fedora 20) I have an sd magnetic hard drive partitioned into /boot, /, /home, etc. I have just acquired another drive of the same geometry. Is it possible to configure a md mirrored ...
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80 views

MD RAID Array Often Starts Without All Drives

I find that, when I start/restart my system, my MD array often doesn't start with all of the drives even though the device-names haven't changed at all. I'll have to stop the array and reassemble it, ...
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In a software RAID1, why does tune2fs -c 0 /dev/sda1 not throw an error but change is not seen in tune2fs -l /dev/sda1?

The Title pretty much says it all. Turn off mount count fsck seems to succeed: tune2fs -c 0 /dev/sda1 tune2fs -c 1 /dev/md0 But listing out via tune2fs -l /dev/sda1 shows mount count is set back ...
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Can RAID 6 support 3 or more parities? [closed]

It doesn't seem right to me that people are using RAID 1+0, RAID 5+0, or RAID 6+0 instead of using a RAID with 3 or more parities (akin to RAID 6) because the latter has a better reliability given the ...
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198 views

Best way to RAID 4 x Intel SSD 910 for PostgreSQL

I have a Linux (debian/ubuntu) server with 4 x Intel SSD 910 800GB pcie that I need to RAID together. The biggest problem with these card is that they give you 4x200GB drives that you cant ...
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206 views

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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59 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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523 views

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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41 views

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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342 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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330 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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164 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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231 views

reusing existing RAIDs on preseeded installation

I'm trying to automate the reinstallation process of existing Ubuntu installations. Partition layout: md0( raid1, /dev/sda1#/dev/sdb1 ) - swap (2G) md1( raid1, /dev/sda2#/dev/sdb2 ) - / (20G) md2( ...
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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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374 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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1k 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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451 views

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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665 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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2k 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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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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137 views

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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154 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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3k 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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157 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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140 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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1k 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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451 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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112 views

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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11k 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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877 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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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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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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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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387 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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144 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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968 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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774 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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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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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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912 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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585 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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3k 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 ...