[lug] RAID1 Versus Mirrored LVM (Fedora 23)

[stimits at comcast.net]

Mostly I'm just trying to safeguard home directory and httpd server directory. Nothing distributed. I do need LVM because I will be balancing out changes in requirements over time, but I also can't afford to lose home, so I need RAID1 qualities. I guess what I'm wondering about is how life differs under a disk failure of RAID1 with LVM on top of it, versus no RAID, but using LVM in its RAID1 equivalent setup (it sounds like LVM uses the same kernel features when doing this as a straight RAID setup would do). Probably the only significant feature on top of this is that I'll probably use the LVM snapshot features for backups. Is there any reason to create a RAID1 partition, and then cover it with LVM, versus just going straight to mirrored LVM setup?
 
----- Original Message -----From: Stephen Kraus <ub3ratl4sf00 at gmail.com>To: Boulder (Colorado) Linux Users Group -- General Mailing List <lug at lug.boulder.co.us>Sent: Sat, 24 Sep 2016 19:21:25 -0000 (UTC)Subject: Re: [lug] RAID1 Versus Mirrored LVM (Fedora 23)

I like RAID, but I also have a ZFS array. ZFS is generally faster, but its more dependant on you to ensure the viability of the array info and health.

On Sep 24, 2016 11:09 AM, <stimits at comcast.net> wrote:

Hi,
 
It's becoming more obvious that I need to dig into details of LVM and RAID. I had originally started out with the intent to produce a mirrored RAID1 on two new disks, and then use that with LVM to divide up the content between "/home" and "/var/www". None of those mount points require booting to them, so this partially simplifies things.
 
Until recently I wasn't even aware that LVM itself can have physical volumes combined into mirrored logical volumes in the same way as RAID1 does. So now I'm wondering if it would be wise to remove the RAID1+LVM design and instead just use LVM with mirroring of two ordinary disk drives. Is there anything special about reliability or performance...or anything else...which would influence the choice of RAID1+LVM versus LVM-with-mirroring? Why would I pick one scheme over the other?
 
Thanks!
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