Persistence of home directory after deleting all partitions and reinstalling:
I was running Ubuntu Server on a mdadm RAID1 volume, and I ran into some problems so I decided to just do a clean install.
I booted with Gparted, stopped the mdadm array, and ran
--zero-superblockon each partition, then deleted the partitions using Gparted.I then booted from an Ubuntu Server USB, configured the raid from scratch using the manual partitioning option, and installed Ubuntu 18.04.
First thing after installing the OS, I installed xfce4 and firefox along with a few other standard utilities and rebooted ran startx and fired up Firefox.
When logged I logged in, the tabs that I had open before reinstallation immediately opened up, I was still logged into SO. In fact, my entire home folder was still there.
I thought I had nuked everything and started fresh. I am totally mystified as to how this happened. Upon further inspection, I saw that all my files in my home folder were still there as well.
Is there some step that I missed? I thought the point of --zero-superblock and deleting the partitions was to get rid of any data on the drive. What did I miss? What does it take to do a guaranteed truly clean install? I am certain I have followed the same exact procedure before and my home directory did not persist.
Edit: So I zeroed out the component drives of the array, but now in the manual setup in the installer, I cannot set my new partition to "bootable" (nothing changes when I select it). Oddly, when creating the partitions it no longer asks me if I want to do a primary or a logical partition as it has in past times USING this same installer usb.
ubuntu system-installation mdadm home
edited Dec 10 at 20:26
Rui F Ribeiro
38.8k1479128
asked Dec 9 at 22:31
Thoughtcraft
1619
add a comment |
I was running Ubuntu Server on a mdadm RAID1 volume, and I ran into some problems so I decided to just do a clean install.
I booted with Gparted, stopped the mdadm array, and ran
--zero-superblockon each partition, then deleted the partitions using Gparted.I then booted from an Ubuntu Server USB, configured the raid from scratch using the manual partitioning option, and installed Ubuntu 18.04.
First thing after installing the OS, I installed xfce4 and firefox along with a few other standard utilities and rebooted ran startx and fired up Firefox.
When logged I logged in, the tabs that I had open before reinstallation immediately opened up, I was still logged into SO. In fact, my entire home folder was still there.
I thought I had nuked everything and started fresh. I am totally mystified as to how this happened. Upon further inspection, I saw that all my files in my home folder were still there as well.
Is there some step that I missed? I thought the point of --zero-superblock and deleting the partitions was to get rid of any data on the drive. What did I miss? What does it take to do a guaranteed truly clean install? I am certain I have followed the same exact procedure before and my home directory did not persist.
Edit: So I zeroed out the component drives of the array, but now in the manual setup in the installer, I cannot set my new partition to "bootable" (nothing changes when I select it). Oddly, when creating the partitions it no longer asks me if I want to do a primary or a logical partition as it has in past times USING this same installer usb.
ubuntu system-installation mdadm home
edited Dec 10 at 20:26
Rui F Ribeiro
38.8k1479128
asked Dec 9 at 22:31
Thoughtcraft
1619
Upvoting not so bad question ... But i think it is for askubuntu.com and not for Unix e Linux?
– Luciano Andress Martini
Dec 9 at 23:16
@LucianoAndressMartini Ubuntu is on topic at U&L SE.
– Christopher
Dec 9 at 23:17
So another reason to upvote that.
– Luciano Andress Martini
Dec 9 at 23:18
add a comment |
I was running Ubuntu Server on a mdadm RAID1 volume, and I ran into some problems so I decided to just do a clean install.
I booted with Gparted, stopped the mdadm array, and ran
--zero-superblockon each partition, then deleted the partitions using Gparted.I then booted from an Ubuntu Server USB, configured the raid from scratch using the manual partitioning option, and installed Ubuntu 18.04.
First thing after installing the OS, I installed xfce4 and firefox along with a few other standard utilities and rebooted ran startx and fired up Firefox.
When logged I logged in, the tabs that I had open before reinstallation immediately opened up, I was still logged into SO. In fact, my entire home folder was still there.
I thought I had nuked everything and started fresh. I am totally mystified as to how this happened. Upon further inspection, I saw that all my files in my home folder were still there as well.
Is there some step that I missed? I thought the point of --zero-superblock and deleting the partitions was to get rid of any data on the drive. What did I miss? What does it take to do a guaranteed truly clean install? I am certain I have followed the same exact procedure before and my home directory did not persist.
Edit: So I zeroed out the component drives of the array, but now in the manual setup in the installer, I cannot set my new partition to "bootable" (nothing changes when I select it). Oddly, when creating the partitions it no longer asks me if I want to do a primary or a logical partition as it has in past times USING this same installer usb.
ubuntu system-installation mdadm home
edited Dec 10 at 20:26
Rui F Ribeiro
38.8k1479128
asked Dec 9 at 22:31
Thoughtcraft
1619
I was running Ubuntu Server on a mdadm RAID1 volume, and I ran into some problems so I decided to just do a clean install.
I booted with Gparted, stopped the mdadm array, and ran
--zero-superblockon each partition, then deleted the partitions using Gparted.I then booted from an Ubuntu Server USB, configured the raid from scratch using the manual partitioning option, and installed Ubuntu 18.04.
First thing after installing the OS, I installed xfce4 and firefox along with a few other standard utilities and rebooted ran startx and fired up Firefox.
When logged I logged in, the tabs that I had open before reinstallation immediately opened up, I was still logged into SO. In fact, my entire home folder was still there.
I thought I had nuked everything and started fresh. I am totally mystified as to how this happened. Upon further inspection, I saw that all my files in my home folder were still there as well.
Is there some step that I missed? I thought the point of --zero-superblock and deleting the partitions was to get rid of any data on the drive. What did I miss? What does it take to do a guaranteed truly clean install? I am certain I have followed the same exact procedure before and my home directory did not persist.
Edit: So I zeroed out the component drives of the array, but now in the manual setup in the installer, I cannot set my new partition to "bootable" (nothing changes when I select it). Oddly, when creating the partitions it no longer asks me if I want to do a primary or a logical partition as it has in past times USING this same installer usb.
ubuntu system-installation mdadm home
ubuntu system-installation mdadm home
edited Dec 10 at 20:26
Rui F Ribeiro
38.8k1479128
asked Dec 9 at 22:31
Thoughtcraft
1619
edited Dec 10 at 20:26
Rui F Ribeiro
38.8k1479128
asked Dec 9 at 22:31
Thoughtcraft
1619
edited Dec 10 at 20:26
Rui F Ribeiro
38.8k1479128
edited Dec 10 at 20:26
Rui F Ribeiro
38.8k1479128
edited Dec 10 at 20:26
Rui F Ribeiro
38.8k1479128
38.8k1479128
asked Dec 9 at 22:31
Thoughtcraft
1619
asked Dec 9 at 22:31
Thoughtcraft
1619
asked Dec 9 at 22:31
Thoughtcraft
1619
1619
Upvoting not so bad question ... But i think it is for askubuntu.com and not for Unix e Linux?
– Luciano Andress Martini
Dec 9 at 23:16
@LucianoAndressMartini Ubuntu is on topic at U&L SE.
– Christopher
Dec 9 at 23:17
So another reason to upvote that.
– Luciano Andress Martini
Dec 9 at 23:18
add a comment |
Upvoting not so bad question ... But i think it is for askubuntu.com and not for Unix e Linux?
– Luciano Andress Martini
Dec 9 at 23:16
@LucianoAndressMartini Ubuntu is on topic at U&L SE.
– Christopher
Dec 9 at 23:17
So another reason to upvote that.
– Luciano Andress Martini
Dec 9 at 23:18
Upvoting not so bad question ... But i think it is for askubuntu.com and not for Unix e Linux?
– Luciano Andress Martini
Dec 9 at 23:16
Upvoting not so bad question ... But i think it is for askubuntu.com and not for Unix e Linux?
– Luciano Andress Martini
Dec 9 at 23:16
@LucianoAndressMartini Ubuntu is on topic at U&L SE.
– Christopher
Dec 9 at 23:17
@LucianoAndressMartini Ubuntu is on topic at U&L SE.
– Christopher
Dec 9 at 23:17
So another reason to upvote that.
– Luciano Andress Martini
Dec 9 at 23:18
So another reason to upvote that.
– Luciano Andress Martini
Dec 9 at 23:18
add a comment |
2 Answers
2
active
oldest
votes
The partition table is really just a piece of data that says things like
- Partition 1 starts at track 10 and finishes at track 99
- Partition 2 starts at track 100 and finishes at track 599
- Partition 3 starts at track 600 and finishes at track 16383
If you delete the partition table then the data in tracks 10->99, 100->599, 600->16383 are untouched, just the OS no longer knows how to find it. So if you then recreate the paritition table exactly the same way then your data is still available. I made use of this in 2016 when I destroyed all my partition tables by mistake ( https://www.sweharris.org/post/2016-02-10-break-mbr/ )
If you want to delete the data inside the partitions as well then you either need to zero the whole disk, or else format the partitions. Most installers have an option to say "format partition" when you do your setup.
Or make sure your partitions start in different places (eg 9->100, 101->600, 601->16384) so the data inside doesn't look like a filesystem.
answered Dec 9 at 23:19
Stephen Harris
24.4k24477
Like what I said...
– Michael Prokopec
Dec 9 at 23:20
add a comment |
Likely you remand the partitions exactly but did not make new file systems.
mkfs.ext4 /dev/sda1
Other possibilities; Firefox (ubuntu, google, microsoft) can backup stuff to a cloud if you are logged in.
There are 2 ways to ensure local data is removed security removed;
Use FDE
cryptsetup luksFormat /dev/sda
Zero the whole drive
cat /dev/zero > /dev/sda
Simply remaking partitions and file systems will certainly make the data require extra work (PhotoRec) to recover.
answered Dec 9 at 23:22
user1133275
2,826519
I didn't login, rather my login persisted across installations.
– Thoughtcraft
Dec 9 at 23:29
add a comment |
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2 Answers
2
active
oldest
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2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
The partition table is really just a piece of data that says things like
- Partition 1 starts at track 10 and finishes at track 99
- Partition 2 starts at track 100 and finishes at track 599
- Partition 3 starts at track 600 and finishes at track 16383
If you delete the partition table then the data in tracks 10->99, 100->599, 600->16383 are untouched, just the OS no longer knows how to find it. So if you then recreate the paritition table exactly the same way then your data is still available. I made use of this in 2016 when I destroyed all my partition tables by mistake ( https://www.sweharris.org/post/2016-02-10-break-mbr/ )
If you want to delete the data inside the partitions as well then you either need to zero the whole disk, or else format the partitions. Most installers have an option to say "format partition" when you do your setup.
Or make sure your partitions start in different places (eg 9->100, 101->600, 601->16384) so the data inside doesn't look like a filesystem.
answered Dec 9 at 23:19
Stephen Harris
24.4k24477
Like what I said...
– Michael Prokopec
Dec 9 at 23:20
add a comment |
The partition table is really just a piece of data that says things like
- Partition 1 starts at track 10 and finishes at track 99
- Partition 2 starts at track 100 and finishes at track 599
- Partition 3 starts at track 600 and finishes at track 16383
If you delete the partition table then the data in tracks 10->99, 100->599, 600->16383 are untouched, just the OS no longer knows how to find it. So if you then recreate the paritition table exactly the same way then your data is still available. I made use of this in 2016 when I destroyed all my partition tables by mistake ( https://www.sweharris.org/post/2016-02-10-break-mbr/ )
If you want to delete the data inside the partitions as well then you either need to zero the whole disk, or else format the partitions. Most installers have an option to say "format partition" when you do your setup.
Or make sure your partitions start in different places (eg 9->100, 101->600, 601->16384) so the data inside doesn't look like a filesystem.
answered Dec 9 at 23:19
Stephen Harris
24.4k24477
Like what I said...
– Michael Prokopec
Dec 9 at 23:20
add a comment |
The partition table is really just a piece of data that says things like
- Partition 1 starts at track 10 and finishes at track 99
- Partition 2 starts at track 100 and finishes at track 599
- Partition 3 starts at track 600 and finishes at track 16383
If you delete the partition table then the data in tracks 10->99, 100->599, 600->16383 are untouched, just the OS no longer knows how to find it. So if you then recreate the paritition table exactly the same way then your data is still available. I made use of this in 2016 when I destroyed all my partition tables by mistake ( https://www.sweharris.org/post/2016-02-10-break-mbr/ )
If you want to delete the data inside the partitions as well then you either need to zero the whole disk, or else format the partitions. Most installers have an option to say "format partition" when you do your setup.
Or make sure your partitions start in different places (eg 9->100, 101->600, 601->16384) so the data inside doesn't look like a filesystem.
answered Dec 9 at 23:19
Stephen Harris
24.4k24477
The partition table is really just a piece of data that says things like
- Partition 1 starts at track 10 and finishes at track 99
- Partition 2 starts at track 100 and finishes at track 599
- Partition 3 starts at track 600 and finishes at track 16383
If you delete the partition table then the data in tracks 10->99, 100->599, 600->16383 are untouched, just the OS no longer knows how to find it. So if you then recreate the paritition table exactly the same way then your data is still available. I made use of this in 2016 when I destroyed all my partition tables by mistake ( https://www.sweharris.org/post/2016-02-10-break-mbr/ )
If you want to delete the data inside the partitions as well then you either need to zero the whole disk, or else format the partitions. Most installers have an option to say "format partition" when you do your setup.
Or make sure your partitions start in different places (eg 9->100, 101->600, 601->16384) so the data inside doesn't look like a filesystem.
answered Dec 9 at 23:19
Stephen Harris
24.4k24477
edited Dec 9 at 23:20
answered Dec 9 at 23:19
Stephen Harris
24.4k24477
answered Dec 9 at 23:19
Stephen Harris
24.4k24477
answered Dec 9 at 23:19
Stephen Harris
24.4k24477
24.4k24477
Like what I said...
– Michael Prokopec
Dec 9 at 23:20
add a comment |
Like what I said...
– Michael Prokopec
Dec 9 at 23:20
Like what I said...
– Michael Prokopec
Dec 9 at 23:20
Like what I said...
– Michael Prokopec
Dec 9 at 23:20
add a comment |
Likely you remand the partitions exactly but did not make new file systems.
mkfs.ext4 /dev/sda1
Other possibilities; Firefox (ubuntu, google, microsoft) can backup stuff to a cloud if you are logged in.
There are 2 ways to ensure local data is removed security removed;
Use FDE
cryptsetup luksFormat /dev/sda
Zero the whole drive
cat /dev/zero > /dev/sda
Simply remaking partitions and file systems will certainly make the data require extra work (PhotoRec) to recover.
answered Dec 9 at 23:22
user1133275
2,826519
I didn't login, rather my login persisted across installations.
– Thoughtcraft
Dec 9 at 23:29
add a comment |
Likely you remand the partitions exactly but did not make new file systems.
mkfs.ext4 /dev/sda1
Other possibilities; Firefox (ubuntu, google, microsoft) can backup stuff to a cloud if you are logged in.
There are 2 ways to ensure local data is removed security removed;
Use FDE
cryptsetup luksFormat /dev/sda
Zero the whole drive
cat /dev/zero > /dev/sda
Simply remaking partitions and file systems will certainly make the data require extra work (PhotoRec) to recover.
answered Dec 9 at 23:22
user1133275
2,826519
I didn't login, rather my login persisted across installations.
– Thoughtcraft
Dec 9 at 23:29
add a comment |
Likely you remand the partitions exactly but did not make new file systems.
mkfs.ext4 /dev/sda1
Other possibilities; Firefox (ubuntu, google, microsoft) can backup stuff to a cloud if you are logged in.
There are 2 ways to ensure local data is removed security removed;
Use FDE
cryptsetup luksFormat /dev/sda
Zero the whole drive
cat /dev/zero > /dev/sda
Simply remaking partitions and file systems will certainly make the data require extra work (PhotoRec) to recover.
answered Dec 9 at 23:22
user1133275
2,826519
Likely you remand the partitions exactly but did not make new file systems.
mkfs.ext4 /dev/sda1
Other possibilities; Firefox (ubuntu, google, microsoft) can backup stuff to a cloud if you are logged in.
There are 2 ways to ensure local data is removed security removed;
Use FDE
cryptsetup luksFormat /dev/sda
Zero the whole drive
cat /dev/zero > /dev/sda
Simply remaking partitions and file systems will certainly make the data require extra work (PhotoRec) to recover.
answered Dec 9 at 23:22
user1133275
2,826519
edited Dec 10 at 14:49
answered Dec 9 at 23:22
user1133275
2,826519
answered Dec 9 at 23:22
user1133275
2,826519
answered Dec 9 at 23:22
user1133275
2,826519
2,826519
I didn't login, rather my login persisted across installations.
– Thoughtcraft
Dec 9 at 23:29
add a comment |
I didn't login, rather my login persisted across installations.
– Thoughtcraft
Dec 9 at 23:29
I didn't login, rather my login persisted across installations.
– Thoughtcraft
Dec 9 at 23:29
I didn't login, rather my login persisted across installations.
– Thoughtcraft
Dec 9 at 23:29
add a comment |
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Upvoting not so bad question ... But i think it is for askubuntu.com and not for Unix e Linux?
– Luciano Andress Martini
Dec 9 at 23:16
@LucianoAndressMartini Ubuntu is on topic at U&L SE.
– Christopher
Dec 9 at 23:17
So another reason to upvote that.
– Luciano Andress Martini
Dec 9 at 23:18