#mdraid

2025-04-02

My home NAS runs mdraid RAID1 on top of two HDDs, each of which is covered by dm-integrity to guard against silent data corruption. Due to how dm-integrity lays out its data, the read-write performance is about half of what the hardware is capable of. I moved dm-integrity tags onto a separate disk to improve the situation, and bumped into a few problems along the way. More details in my blog: blog.tty8.org/posts/2025-04-02

#linux #mdraid #dmintegrity

2025-02-27

Am I reading the Linux #mdadm manpage correctly?

AIUI it says that the property of whether a RAID whose component devices are found is auto-assembled is a property of only the mdadm.conf file on the host doing the assembly.

What I need to have is, like on classic BSD RAIDframe, to encode into the superblock of the component devices that the RAID must never be auto-assembled. Is this truly not possible with Linux #mdraid?

(Background: the components are protected with dm-integrity but in split setup, i.e. a separate --data-device, which GRUB is indeed allowed to assemble* in read-only mode, to boot from it. But e.g. a grml.org @grmlproject or a Hetzner rescue system is not allowed to assemble it because otherwise the integrity of the superblock goes kaboom. I know I can boot Grml with the forensic boot option, but…)

*) It’s a RAID 1 for /boot so in theory no assembly even needed for GRUB, no idea what it actually does.

Jürgenelbosso
2024-12-16

So hatte ich mir meinen Weihnachtsurlaub nicht vorgestellt: eine Platte meines im ist gestorben und muss ersetzt werden... Eigentlich hatte ich mit meinem Weihnachtsbonus was anderes vor: kleine Städtereise vllt. Oder mal ansehen. Schnief...
Aber: gibt schlimmeres - viel schlimmeres!

Alexey Skobkinskobkin@lor.sh
2024-10-23

Есть всё-таки что-то прекрасное в профессиональных инструментах, которые просто делают то, что нужно.

я: mdadm, собери мне, пожалуйста, из коробки деградировавший RAID 6 на пять дисков из четырёх дисков.
mdadm: готово, вот твой новенький деградировавший RAID!

#soft #server #RAID #mdraid #Linux #log #thoughts

2024-07-26

Влияние MD checking на производительность и методы уменьшения влияния на работоспособность системы

MD (Multiple Device) — это технология в Linux, которая позволяет объединять несколько физических дисков в один логический накопитель с помощью различных схем RAID (Redundant Array of Independent Disks). mdXXX (далее md disk) — это одино из устройств, созданных с использованием этой технологии. Для определения влияния проверки состояния (checking) массива md disk на производительность системы необходимо рассмотреть несколько аспектов.

habr.com/ru/articles/831718/

#mdraid #ionice #cgroups #checking

Christiaan :bazzite: :flag_nl:RyuKurisu@fosstodon.org
2022-06-22

have build in #RAID support, to that'll probably be handled by either #LVM or #MDraid, but it also doesn't do checksumming like #Btrfs / #ZFS so you don't know if/when you get bit-rot 🤔

Some articles mention #GRUB supports booting from NILFS2, but an other (possibly a #Calamares bug at the time) did not but provided a workaround.

All ideas on how to improve my setup are very welcome #100DaysOfHomeLab #Day2of100 - 2/2

Alexander Bochmanngalaxis@mastodon.infra.de
2022-06-04

Do md RAID1 arrays do partial recovery nowadays? I just booted a system with one drive not properly connected. After fixing the problem, the array was degraded ("md: kicking non-fresh sdb2 from array!"). After re-adding the device, a rebuild started ... and was finished within 10 minutes or so (for a 1.8TB mirror). A complete rebuild takes maybe two hours?

#Linux #mdraid

2022-04-11

MD-Raid5 aus 3 Platten, dd nach /dev/null der Einzelplatten:
166 MB/s, 222 MB/s und 161 MB/s
md device: 35,7 MB/s 😐
Testmässig aufgesetztes BTRFS-Raid5 aus 4 Platten: 158 MB/s
Hat da wer eine Idee?
#raid #raid5 #mdraid

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