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From: L A Walsh <lvm@tlinx.org>
Date: Tue, 21 Jul 2020 17:23:47 -0700
Message-ID: <CALOnQv5gib+tQTBzZBD9QDDNiZcuoybN3HoH_wQVD8rAdsMQKA@mail.gmail.com>
Subject: [linux-lvm] lvm question regarding start and placement of data
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To: linux-lvm@redhat.com

I have a file in the /etc/lvm/archive dir that seems to be the name of a vg.


I see:
Data {
    seqno = 1933
    format = "lvm2" # informational
    status = ["RESIZEABLE", "READ", "WRITE"]
    extent_size = 8192        # 4 Megabytes
    max_lv = 0
    max_pv = 0
    metadata_copies = 0

    physical_volumes {
        pv0 {
            device = "/dev/sdb1"    # Hint only
            status = ["ALLOCATABLE"]
            flags = []
            dev_size = 93755273216    # 43.6582 Terabytes
            pe_start = 2048
            pe_count = 11444735    # 43.6582 Terabytes
        }
    }

    logical_volumes {
        Home {
            allocation_policy = "contiguous"
            segment_count = 1
            segment1 {
                start_extent = 0
                extent_count = 393216    # 1.5 Terabytes
                type = "striped"
                stripe_count = 1    # linear
                stripes = [ "pv0", 0 ]
            }
        }
----
It appears that the start of the physical vol is at 2048 but not sure
what the units are --
Are those 2048 physical extents of size 8192 and is said to be
equivalent to 4MB?  So the 8192 is a number of 512 byte sectors
(even though they underlying disk is 4K with 512e)?

At the start of the physical volume at 2048 should I see the logical
volume 'Home' as it starts at extent '0'?

So shouldn't I see the start of the Home partition 8MB in from the
front?  Or is there something else before physical volumns?  Does
first logical volume start at pe_start?

I.e. I'm assuming I have something wrong, because I'm not seeing anything
looking like the beginning of a file system at that location...

Thanks....