Questions tagged [md]

Multiple Device driver aka Linux Software RAID

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23 views

Dismounting MD RAID1 LUKS-encrypted volume with partitions

Fedora 29. I created a 5TB RAID1 volume using mdadm. I then encrypted the volume with cryptsetup luksFormat. I then created ext4 partitions on the encrypted volume. (I did it this way so I can add ...
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1answer
75 views

mdadm: Resume initial sync

I have a new md RAID10 that I created (on a Synology DS416slim, which is besides the point), which was in the process of initial sync: root@ds416slim:~# cat /proc/mdstat Personalities : [linear] [...
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2answers
345 views

MD RAID - disable NCQ

Why is it recommended in a MD RAID (mdadm) to disable NCQ per-disk? echo 1 > /sys/block/sdX/device/queue_depth I read this tip in many articles regarding RAID tuning but nobody explains why.
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20 views

KVM configuration for a Windows VM with Software MD Raid

Under Fedora Server I created a MD Raid 10. I also installed KVM.I will create a Windows VM and I need that this VM uses all the space in the MD Raid 10 formatted by Windows under NTFS with the best ...
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1answer
66 views

(Why) Does lvmraid6 need 5 drives?

I'm investigating using LVMRAID instead of MD+LVM. In my case, I'm looking at a RAID6. As expected, the docs say you need N+1 devices for RAID5, and a minimum of 3 drives. The docs say for RAID 6 ...
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1answer
40 views

How to pre-emptively repair/replace drive in linux md array without going degraded first?

I have (had, it's already been swapped out, asking this for future use) a drive that is indicating pending failure with internal SMART tests and bad block remaps. It is straightforward to mdadm --...
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1answer
78 views

Teaming a drive in multiple RAID groups [closed]

I've setup a home RAID for a friend in the past from a heap of old and new 2T and 3T drives. seems very much like what BeyondRAID does. I made a 7 member RAID5 group of the 2T volumes and the first ...
2
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1answer
395 views

Data scrubbing and repairing a RAID1 mirror?

In Linux, if I have a software RAID1 mirror /dev/md1 with N ≥ 1 active devices, what are the semantics of the repair command? echo "repair" >/sys/block/md1/md/sync_action Am I correct to ...
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2answers
757 views

md raid fails to boot with missing drive

I got a server with Debian Jessie, 4 Drives sda to sdd all of which are partitioned likewise. The system is in a raid1 md raid over all drives. All drives do have grub and I can swap discs with each ...
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3answers
5k views

How to re-add a drive when RAID is in degraded mode?

I am running an unmanaged Ubuntu server and due to recent performance issue and sent a request to the provider only to receive the following response: "Dear Client, as requested we have checked ...
2
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1answer
358 views

GPT, grub and mdadm. sda drive replaced, raid rebuilt in recovery mode, but now server won't boot

This is how partition table loooks like: (parted) print Model: ATA TOSHIBA DT01ACA2 (scsi) Disk /dev/sda: 2000GB Sector size (logical/...
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1answer
253 views

How to keep md-raid from blocking IO?

I run a server with md-raid (software) level 1 (2 HDDs mirroring) and several different applications run on it. The problem arises when file-intensive jobs (e.g. extracting large archives) run while ...
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2answers
571 views

Degraded md RAID5 won't boot

I'm running a Ubuntu server on a md RAID5. I started to have some issue with one disk, I received the following email from mdadm: A DegradedArray event had been detected on md device /dev/md/0. md0 : ...
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1answer
399 views

raid0 (soft-RAID using Linux md drivers) hosting XFS: how to repair after replacing bad disk?

So the latest configuration of our Nova compute nodes are using raw /dev/sdX devices (no labels nor partitions) as components for an md0 (raid0) array on which they're hosting an XFS filesystem. When ...
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1answer
794 views

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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1answer
417 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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2answers
46 views

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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2answers
329 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 ...
4
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1answer
555 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) sdb1[...
3
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1answer
355 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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0answers
254 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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3answers
572 views

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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1answer
477 views

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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1answer
401 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 hardware-...
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1answer
1k 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 ...
1
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1answer
260 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 ...
1
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1answer
1k 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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1answer
64 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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1answer
780 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 Vendors,...
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1answer
1k 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
331 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 ...
5
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1answer
495 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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1answer
155 views

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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0answers
621 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 ...
4
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2answers
2k 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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2answers
576 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 ...
2
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1answer
824 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: Serious ...
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2answers
4k 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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3answers
2k 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
154 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 ...
1
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1answer
523 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 "...
3
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2answers
4k 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. ...
3
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2answers
280 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, ...
2
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1answer
172 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 /...
3
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2answers
2k 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 drive....
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2answers
554 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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0answers
143 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 lock-in....
6
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2answers
24k 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
1k 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 "...
6
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1answer
2k 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 ...