MDADM vs LVM

Runaway1956 · 2015-09-04 16:30:34

Well - I've been collecting odds and ends from around the internet for years now. Many years. I have a pile of hard disks that I really need to go through, salvage what I want to save, then do something with all those hard drives. Ebay, maybe.

So - I ordered some 2Tb disks. I did some homework on RAID arrays, and was nearly settled on a RAID5. But, during the course of learning the do's and dont's of RAID arrays, I found considerable advice scattered around the web regarding LVM. Primarily, LVM is much easier to shrink and/or grow than a RAID is. And, you don't lose as much space in an LVM for parity.

I would love to hear what members think about RAID vs LVM. I have three or four days before my disks are delivered - maybe someone would like to make my mind up for me?

The drives in question: IBM/Hitachi Ultrastar A7K2000 2TB HUA722020ALA330 (0F10632) 2TB 32MB Cache 7200RPM SATA 3.0Gb/s (Heavy Duty) Enterprise 3.5" Hard Drive

alphaniner · 2015-09-04 17:04:44

I would love to hear what members think about RAID vs LVM

On my systems, RAID (mdadm) and LVM cooperate rather than compete.
I generally create a single LVM VG on an mdadm RAID10. AFAICT this kind of setup (LVM-on-mdadm) is the most common means of using LVM with multiple disks for a "RAID-like solution".

Have you seen this?

Runaway1956 · 2015-09-05 01:25:16

I had not seen that, alphaniner - thanks for the link. Reading it now!

Runaway1956 · 2015-09-05 01:47:45

Oh - the archwiki has a page on the very same subject, alphaniner!

https://wiki.archlinux.org/index.php/So … ID_and_LVM

Soukyuu · 2015-09-05 11:53:37

With regards to RAID, you might want to read this as well.

frostschutz · 2015-09-05 12:23:02

I prefer to use mdadm for RAID rather than LVM's RAID modes. I do like LVM (for regular logical volumes, no shenanigans) on top of RAID (and everywhere else, really).

Last edited by frostschutz (2015-09-05 12:23:44)

Runaway1956 · 2015-09-08 21:38:30

Whew - disks arrived today. I've physically installed them, but I'm not ready yet to format and RAID them. I'm still studying the GPTfdisk tools! This is a whole different world than I've played around in, in the past! Luckily, it's all empty disks, and I can screw it up a time or six without losing anything more than time!

Runaway1956 · 2015-09-11 01:55:27

Yay! I've finally struggled through the learning curve! Alright, it's not THAT difficult, but like anything else, until you've done it, you don't understand it.

Four disks in RAID 5, with with LVM managing the volumes. Most of the guides I found were aimed at making LVM bootable, but all I want is data storage. For my own personal immediate use, I've created a 500 GB volume, and mounted it to ~/lvmpart. That is sufficient for now to move files off of two hard drives. Some time in the future (mabe tomorrow, maybe next month) I'll create another volume or two, remove those hard drives from the computer, and start plugging in other hard drives.

There's no real pressure to get this done - if I were serious about it, I could probably have it finished before the week is out.

Solving this problem also solves another related problem. The wife is talking about more storage. I can now offer her some network space on the RAID, and/or I can offer her some hard drives, as I move files off of them.

Arch Linux

#1 2015-09-04 16:30:34

MDADM vs LVM

#2 2015-09-04 17:04:44

Re: MDADM vs LVM

#3 2015-09-05 01:25:16

Re: MDADM vs LVM

#4 2015-09-05 01:47:45

Re: MDADM vs LVM

#5 2015-09-05 11:53:37

Re: MDADM vs LVM

#6 2015-09-05 12:23:02

Re: MDADM vs LVM

#7 2015-09-08 21:38:30

Re: MDADM vs LVM

#8 2015-09-11 01:55:27

Re: MDADM vs LVM

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