From: "Tomas Dalebjörk" <tomas.dalebjork@gmail.com>
To: Mikulas Patocka <mpatocka@redhat.com>
Cc: LVM general discussion and development <linux-lvm@redhat.com>,
Zdenek Kabelac <zkabelac@redhat.com>
Subject: Re: [linux-lvm] exposing snapshot block device
Date: Fri, 4 Sep 2020 14:09:47 +0200 [thread overview]
Message-ID: <0B002628-0740-4DA4-A9BD-320A743A7A30@gmail.com> (raw)
In-Reply-To: <CACrcyfJBtsVFwf8wFjDAc1sOKPiOVBJjKbDC3c+3G-z6v5SCpA@mail.gmail.com>
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hi
I tried to perform as suggested
# lvconvert —splitsnapshot vg/lv-snap
works fine
# lvconvert -s vg/lv vg/lv-snap
works fine too
but...
if I try to converting cow data directly from the meta device, than it doesn’t work
eg
# lvconvert -s vg/lv /dev/mycowdev
the tool doesn’t like the path
I tried to place a link in /dev/vg/mycowdev -> /dev/mycowdev
and retried the operations
# lvconveet -s vg/lv /dev/vg/mycowdev
but this doesn’t work either
conclusion
even though the cow device is an exact copy of the cow device that I have saved on /dev/mycowdev before the split, it wouldn’t work to use to convert back as a lvm snapshot
not sure if I understand the tool correctly, or if there are other things needed to perform, such as creating virtual information about the lvm VGDA data on the first of this virtual volume named /dev/mycowdev
let me know what more steps are needed
beat regards Tomas
Sent from my iPhone
> On 7 Nov 2019, at 18:29, Tomas Dalebjörk <tomas.dalebjork@gmail.com> wrote:
>
>
> Great, thanks!
>
> Den tors 7 nov. 2019 kl 17:54 skrev Mikulas Patocka <mpatocka@redhat.com>:
>>
>>
>> On Tue, 5 Nov 2019, Tomas Dalebjörk wrote:
>>
>> > Thanks,
>> >
>> > That really helped me to understand how the snapshot works.
>> > Last question:
>> > - lets say that block 100 which is 1MB in size is in the cow device, and a write happen that wants to something or all data on that region of block 100.
>> > Than I assume; based on what have been previously said here, that the block in the cow device will be overwritten with the new changes.
>>
>> Yes, the block in the cow device will be overwritten.
>>
>> Mikulas
>>
>> > Regards Tomas
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next prev parent reply other threads:[~2020-09-04 12:09 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-22 10:47 [linux-lvm] exposing snapshot block device Dalebjörk, Tomas
2019-10-22 13:57 ` Zdenek Kabelac
2019-10-22 15:29 ` Dalebjörk, Tomas
2019-10-22 15:36 ` Zdenek Kabelac
2019-10-22 16:13 ` Dalebjörk, Tomas
2019-10-23 10:26 ` Zdenek Kabelac
2019-10-23 10:56 ` Tomas Dalebjörk
2019-10-22 16:15 ` Stuart D. Gathman
2019-10-22 17:02 ` Tomas Dalebjörk
2019-10-22 21:38 ` Gionatan Danti
2019-10-22 22:53 ` Stuart D. Gathman
2019-10-23 6:58 ` Gionatan Danti
2019-10-23 10:06 ` Tomas Dalebjörk
2019-10-23 10:12 ` Zdenek Kabelac
2019-10-23 10:46 ` Zdenek Kabelac
2019-10-23 11:08 ` Gionatan Danti
2019-10-23 11:24 ` Tomas Dalebjörk
2019-10-23 11:26 ` Tomas Dalebjörk
2019-10-24 16:01 ` Zdenek Kabelac
2019-10-25 16:31 ` Tomas Dalebjörk
2019-11-04 5:54 ` Tomas Dalebjörk
2019-11-04 10:07 ` Zdenek Kabelac
2019-11-04 14:40 ` Tomas Dalebjörk
2019-11-04 15:04 ` Zdenek Kabelac
2019-11-04 17:28 ` Tomas Dalebjörk
2019-11-05 16:24 ` Zdenek Kabelac
2019-11-05 16:40 ` Mikulas Patocka
2019-11-05 20:56 ` Tomas Dalebjörk
2019-11-06 9:22 ` Zdenek Kabelac
2019-11-07 16:54 ` Mikulas Patocka
2019-11-07 17:29 ` Tomas Dalebjörk
2020-09-04 12:09 ` Tomas Dalebjörk [this message]
2020-09-04 12:37 ` Zdenek Kabelac
2020-09-07 13:09 ` Mikulas Patocka
2020-09-07 14:14 ` Dalebjörk, Tomas
2020-09-07 14:17 ` Zdenek Kabelac
2020-09-07 16:34 ` Tomas Dalebjörk
2020-09-07 16:42 ` Zdenek Kabelac
2020-09-07 17:37 ` Tomas Dalebjörk
2020-09-07 17:50 ` Zdenek Kabelac
2020-09-08 12:32 ` Dalebjörk, Tomas
2020-09-07 19:56 ` Tomas Dalebjörk
2020-09-07 20:22 ` Tomas Dalebjörk
2020-09-07 21:02 ` Tomas Dalebjörk
2019-10-23 12:12 ` Ilia Zykov
2019-10-23 12:20 ` Ilia Zykov
2019-10-23 13:05 ` Zdenek Kabelac
2019-10-23 14:40 ` Gionatan Danti
2019-10-23 15:46 ` Ilia Zykov
2019-10-23 12:59 ` Zdenek Kabelac
2019-10-23 14:37 ` Gionatan Danti
2019-10-23 15:37 ` Zdenek Kabelac
2019-10-23 17:16 ` Gionatan Danti
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