On Thursday, 02-01-2025 at 15:22 gene heskett wrote:
>
> On 1/1/25 21:57, Max Nikulin wrote:
> > On 01/01/2025 00:55, Andrew M.A. Cater wrote:
> >> On Mon, Dec 30, 2024 at 11:32:17PM -0500, gene heskett wrote:
> >>>> Good question Marc. I'm searching for someone who knows how to
> >>>> combine 4
> >>>> ea 4T SSD's into one volume for use with amanda, the lvm docs are
> >>>> somewhat confusing, lacking the context that actually teaches.
> > [...]
> >> 2. In the installer, use the RAID element to set up the disks as one
> >> md array
> >>
> >> That will give you one md partition spanning the four disks.
> >
> > I suspect that Gene is just going to configure LVM on a running system
> > and it is completely unrelated to UEFI (so it is purely off-topic) and
> > to the installer.
> >
> This, since I've not done this yet, is quit likely true.
> > The problem is that he can not use some search engine to find guides
> > related to LVM. He believes that everything must be documented in man
> > pages, but he ignores any tool that may help to find locally installed
> > man pages.
> Sensible spelling of the utility's that do that would help that search
> effort considerably. I note that I've rx'd detailed help assuming I am
> using the installer, but no one has offered to teach me exactly what to
> type into a bash shell on a system that is booted to a working cli. I
> want to make a raid10 of nearly 8T out a 4 of these 4T drives. Do I
> even need LVM for a raid10 out of 4, 4T drives?.
I apologise for replying even after I now realise how little I truly
understand LVM, maybe I will do some personal study on the topic.
I like the idea of RAID 10. I have read that it provides best performance for
Database systems.
I once used/tested with RAID 6 and was amazed how long it took to rebuild a 3TB
swapped hard drive (about 8 hours, if I recall).
I do not believe you need LVM. But then I do not know what you are going to do
with the RAID volume. Will you one day extend the RAID volume to 6 or 8 drives?
How do you want to present its storage to your operating system? (e.g. One
large partition, or smaller partitions. Will you allocate all of the storage
straight away, or will you reserve some unallocated storage for later extending
the partitions you first created?)
This is my understanding of LVM:
I have great admiration for LVM, it is stable, efficient, and seems low on over
head.
LVM was introduced to allow extending storage by adding extra physical drives.
Storage space is allocated as virtualised storage, i.e. Logical Volumes.
But if these drives do not have redundancy, for example, RAID, the lost of any
one drive can be catastrophic to the Local Volume to which the failed drive's
storage was allocated to.
Hence if using LVM, I would always want to have the physical storage protected
by some level of RAID which provides redundancy.
Extending virtual volumes is not the only benefit from using LVM. Because of
the physical storage being abstracted, backing up of live systems is possible,
and I believe there is similar advances for managing Virtual Machines,
including things like background virus checking.
I believe BTRFS provides some of these benefits too, which leads people to
question whether to use LVM on top of BTRFS file systems.
I have never implemented LVM for my own systems, as I like to reduce any
unneeded complexity, and I prefer to replace smaller storage with larger
storage, than to extend exiting storage.
I am curious what you will decide and how that decision works out for you.
There is so much IT I would love to explore.
George.
Some reading for me later:
https://www.baeldung.com/linux/btrfs-lvm
https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/8/html/configuring_and_managing_virtualization/managing-storage-for-virtual-machines_configuring-and-managing-virtualization#managing-storage-for-virtual-machines_configuring-and-managing-virtualization
> >
> > .
>
> Cheers, Gene Heskett, CET.
> --
> "There are four boxes to be used in defense of liberty:
> soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author, 1940)
> If we desire respect for the law, we must first make the law respectable.
> - Louis D. Brandeis
>
>
