[linux-lvm] Securing against data lost

[linux-lvm] Securing against data lost

[Sun_Blood]

Hi

Hope someone have time to answer this because google is not giving me
the answers I need.

I have just started to use LVM(a few years later then everyone) and
I'm wondering how I can protect my self from failure to the LVM setup.
Before when I had for example 3 harddisk at 200gb each (/dev/sd[b-d])
with one partition each and a disk failed I would maximum lose 200gb.
Now with LVM the LV is 600gb I'm worried that I can loose all if one
disk have a problem.

So how can I protect myself from this?
What happens if I accidental destroys the LVM information?
What happens if the first disk fails do I lose everything on the two
second disk too?

Best regards
Martin

Re: [linux-lvm] Securing against data lost

[Ray Morris]

Obviously the number one answer on how to prevent data loss
is PROPER back up. That means off site, with multiple time 
points, so you can go back to an earlier back up if you 
recognize  problem a couple of days later.

> What happens if I accidental destroys the LVM information?

You use vgcfgrestore.

> What happens if the first disk fails do I lose everything on the two
> second disk too?

When a disk fails (not if) you replace it and rebuild the array.

Not using any RAID _and_ don't have a proper back up? In that 
case, retrieving the files from the other two disks could be a 
pain. It would be essentially the same thing as if you ran this 
to zero the first third of a filesystem:

dd if=/dev/zero of=/dev/sda2 bs=1024 count=66000000

You could probably restore some files from the last 2/3rds 
of the filesystem, but that would be a question for people 
who know about whatever filesystem was in use.
-- 
Ray Morris
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On Wed, 10 Aug 2011 13:40:05 +0200
Sun_Blood <sblood@gmail.com> wrote:

> Hi
> 
> Hope someone have time to answer this because google is not giving me
> the answers I need.
> 
> I have just started to use LVM(a few years later then everyone) and
> I'm wondering how I can protect my self from failure to the LVM setup.
> Before when I had for example 3 harddisk at 200gb each (/dev/sd[b-d])
> with one partition each and a disk failed I would maximum lose 200gb.
> Now with LVM the LV is 600gb I'm worried that I can loose all if one
> disk have a problem.
> 
> So how can I protect myself from this?
> What happens if I accidental destroys the LVM information?
> What happens if the first disk fails do I lose everything on the two
> second disk too?
> 
> Best regards
> Martin
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> 

Re: [linux-lvm] Securing against data lost

[Georges Giralt]

Le 10/08/2011 13:40, Sun_Blood a �crit :
> Hi
>
> Hope someone have time to answer this because google is not giving me
> the answers I need.
>
> I have just started to use LVM(a few years later then everyone) and
> I'm wondering how I can protect my self from failure to the LVM setup.
> Before when I had for example 3 harddisk at 200gb each (/dev/sd[b-d])
> with one partition each and a disk failed I would maximum lose 200gb.
> Now with LVM the LV is 600gb I'm worried that I can loose all if one
> disk have a problem.
>
> So how can I protect myself from this?
> What happens if I accidental destroys the LVM information?
> What happens if the first disk fails do I lose everything on the two
> second disk too?
>
> Best regards
> Martin
Hello !

Having 3 disk make a RAID a good idea. This will prevent loosing one
disk and loosing all data.
Then making propoer backup prevent from accidental human error or
catastrophic failure.
IMHO you should use a RAID 5 on your disks (either hardware RAID or
software MD RAID) and then build your PV, VG, and LV on top of this
array. Of course, you SHOULD monitor this array to ensure it is running
fine .....
Disk are cheap now, so you should have done this already.
But as other have said, proper backup IS the way to survive....

-- 
If the only tool you have is a hammer, you tend to see every problem as a nail.
                Abraham Maslow
A British variant :
Any tool can serve as a hammer but a screwdriver makes the best chisel.