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Re: LVM not fit for default



Personally I agree with Andy in what he's said before on the part of LVM.


First of all I have experienced the same "no help hell" with lvm when it crashes. (not if, when) I had FC3 installed on my Compaq R3000 Series notebook, default settings, except for package options. Ran that for about three weeks. I reinstall testing out new distros quite a lot, so I don't worry about backing up the entire system, and something happened with the system, the kernel panicked when it couldn't find a root FS. Same problem as andy.

Basically All I'm trying to say is that yes it fails sometime, no it is a cool thing to have, but either give us some tools on default install/rescue disc to combat the issue, or take it out unless the system detects a RAID array.

Thanks guys,

Chris



On Dec 23, 2006, at 8:24 AM, Andy Green wrote:

Callum Lerwick wrote:

When LVM is inflicted on to situations that cannot benefit from it, the end result is you made something more fragile for no gain: that can't be right.
Every PV keeps duplicate copies of the metadata by default. You can
optionally make it store three. Two at the start, one at the end. And
every PV in a VG has a copy of the metadata as well. So with two PVs
that's four copies of the metadata by default, and optionally 6.
... And backing up your LVM metadata to your /boot partition isn't a bad
idea either. As well as an offline backup.
So I have 11 copies of my LVM metadata. That seems rather redundant to
me.

Sounds impressive, but the LVM that was damaged here was not visible nor mountable in Fedora, although the filesystem behind it was mostly intact and mounted okay when I had a copy of it without the LVM stuff in front of it. Googling at the time didn't bring up anything about how to use these proposed copied of "metadata" nor was anything done about them or mentioned about them by the LVM stuff in Fedora, nor have I heard about LVM metadata before today. All the damaged LVM header had for me was to hide my mostly intact filesystem from being fsck'd or mounted.

Further, you are full of care to have 11 copies of something you don't even need in, say, a laptop usage case, in case it breaks (because if it does break, you experience the truth of what I previously related about not being able to get at your filesystem). This looks like a pointless and dangerous burden to place on someone who is getting nothing from having LVM there in the first place. LVM on raid can make sense, in other common usage cases it is only a net risk.

-Andy

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