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I have 3 drives that I want in raid5 to get the most space utilization while still allowing a disk failure. But I want to be able to expand the array later when I have more disks (likely up to 7 disks)

So if I initially create a raid5 array using pv/vg/lvm, can I later expand it by adding a 4th, 5th, etc. disk?

The array is a backup array, not a live array, so load is not an issue.

cclloyd
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  • Please try not to use R5, especially with larger disk - it's been heavily-discouraged for over a decade now – Chopper3 Jan 23 '21 at 14:20
  • @Chopper3 any reason/reading material as to why? – cclloyd Jan 23 '21 at 21:16
  • There's SO much out there - it's borderline negligent for it still to be available tbh - this is literally the first one that came up but there are so many - https://www.zdnet.com/article/why-raid-5-stops-working-in-2009/ – Chopper3 Jan 26 '21 at 09:35

2 Answers2

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You can create a RAID 5 logical volume with LVM and please use this below article for more reference.

RAID 5 LVM

asmath
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Using lvm for raid5 is generally a terrible idea. You should consider using the appropriate raid controller for that, or using zfs.

As about the expanding: usually raid 5 aren't expanding adding more disks in the raid group after some treshold (because this increases the cold data probability and the need to scrub the entire array more often). They are converting/expanding in/to the raid 50 by adding more raid 1 spans into it. Say you have 3 disks in the raid 5: then you could add 4th or even 5th disk into it, if the controller allows this, but adding 6th or 7th disk is then a bad idea. You should convert it to a raid 50 instead, adding the exact number off disks as a span: it means if you already have 5 disks, you should then add 5 more in a span, making it raid 50.

drookie
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