Does pvcreate destroy all the data in a partition?
man pvcreate says
pvcreate initializes a PV so that it is recognized as belonging to LVM, and allows the PV to be
used in a VG. A PV can be a disk partition, whole disk, meta device, or loopback file.
For DOS disk partitions, the partition id should be set to 0x8e using fdisk(8), cfdisk(8), or a
equivalent. For GUID Partition Table (GPT), the id is E6D6D379-F507-44C2-A23C-
238F2A3DF928. For whole disk devices only the partition table must be erased, which will
effectively destroy all data on that disk. This can be done by zeroing the first sector with:
dd if=/dev/zero of=PhysicalVolume bs=512 count=1
If I use pvcreate to mark a disk as a PV, does it mean that pvcreate will destroy all the data on a disk?
If I use pvcreate to mark a partition which contains a filesystem as a PV as a PV, will it destroy all the data in the filesystem?
If yes, does it mean that I can't move a filesystem from a partition to a LV, by pvcreate the partition as a PV (and then lvcreate a LV)?
Thanks.
lvm
asked Feb 24 at 15:56
TimTim
27.8k78265485
add a comment |
man pvcreate says
pvcreate initializes a PV so that it is recognized as belonging to LVM, and allows the PV to be
used in a VG. A PV can be a disk partition, whole disk, meta device, or loopback file.
For DOS disk partitions, the partition id should be set to 0x8e using fdisk(8), cfdisk(8), or a
equivalent. For GUID Partition Table (GPT), the id is E6D6D379-F507-44C2-A23C-
238F2A3DF928. For whole disk devices only the partition table must be erased, which will
effectively destroy all data on that disk. This can be done by zeroing the first sector with:
dd if=/dev/zero of=PhysicalVolume bs=512 count=1
If I use pvcreate to mark a disk as a PV, does it mean that pvcreate will destroy all the data on a disk?
If I use pvcreate to mark a partition which contains a filesystem as a PV as a PV, will it destroy all the data in the filesystem?
If yes, does it mean that I can't move a filesystem from a partition to a LV, by pvcreate the partition as a PV (and then lvcreate a LV)?
Thanks.
lvm
asked Feb 24 at 15:56
TimTim
27.8k78265485
1
What do you mean by "mark the disk as a PV"? Formatting an existing device as a PV will effectively lose said data in the same way that reformating a filesystem with a new filesystem will lose previous files.
– Torin
Feb 24 at 16:05
What do you mean? Marking a device as a PV is not reformating a filesystem with a new filesystem.
– Tim
Feb 24 at 16:24
Both involve removing the structure of a volume and replacing it with a new structure. You don't make a physical volume by "marking" it as such in the same way you don't make a filesystem by "marking" it - it needs formatting
– Torin
Feb 24 at 16:29
1
pvcreatewrites a header block. This may effectively make the data structures (eg the filesystem superblock) unreadable, but the underlying data may be recoverable by a data recovery tool, or bydd. From a typical end-user perspective, doingpvcreateon a block device may render the existing filesystem unreadable.
– Stephen Harris
Feb 24 at 16:35
add a comment |
man pvcreate says
pvcreate initializes a PV so that it is recognized as belonging to LVM, and allows the PV to be
used in a VG. A PV can be a disk partition, whole disk, meta device, or loopback file.
For DOS disk partitions, the partition id should be set to 0x8e using fdisk(8), cfdisk(8), or a
equivalent. For GUID Partition Table (GPT), the id is E6D6D379-F507-44C2-A23C-
238F2A3DF928. For whole disk devices only the partition table must be erased, which will
effectively destroy all data on that disk. This can be done by zeroing the first sector with:
dd if=/dev/zero of=PhysicalVolume bs=512 count=1
If I use pvcreate to mark a disk as a PV, does it mean that pvcreate will destroy all the data on a disk?
If I use pvcreate to mark a partition which contains a filesystem as a PV as a PV, will it destroy all the data in the filesystem?
If yes, does it mean that I can't move a filesystem from a partition to a LV, by pvcreate the partition as a PV (and then lvcreate a LV)?
Thanks.
lvm
asked Feb 24 at 15:56
TimTim
27.8k78265485
man pvcreate says
pvcreate initializes a PV so that it is recognized as belonging to LVM, and allows the PV to be
used in a VG. A PV can be a disk partition, whole disk, meta device, or loopback file.
For DOS disk partitions, the partition id should be set to 0x8e using fdisk(8), cfdisk(8), or a
equivalent. For GUID Partition Table (GPT), the id is E6D6D379-F507-44C2-A23C-
238F2A3DF928. For whole disk devices only the partition table must be erased, which will
effectively destroy all data on that disk. This can be done by zeroing the first sector with:
dd if=/dev/zero of=PhysicalVolume bs=512 count=1
If I use pvcreate to mark a disk as a PV, does it mean that pvcreate will destroy all the data on a disk?
If I use pvcreate to mark a partition which contains a filesystem as a PV as a PV, will it destroy all the data in the filesystem?
If yes, does it mean that I can't move a filesystem from a partition to a LV, by pvcreate the partition as a PV (and then lvcreate a LV)?
Thanks.
lvm
lvm
asked Feb 24 at 15:56
TimTim
27.8k78265485
asked Feb 24 at 15:56
TimTim
27.8k78265485
edited Feb 24 at 16:44
Tim
asked Feb 24 at 15:56
TimTim
27.8k78265485
asked Feb 24 at 15:56
TimTim
27.8k78265485
asked Feb 24 at 15:56
TimTim
27.8k78265485
27.8k78265485
1
What do you mean by "mark the disk as a PV"? Formatting an existing device as a PV will effectively lose said data in the same way that reformating a filesystem with a new filesystem will lose previous files.
– Torin
Feb 24 at 16:05
What do you mean? Marking a device as a PV is not reformating a filesystem with a new filesystem.
– Tim
Feb 24 at 16:24
Both involve removing the structure of a volume and replacing it with a new structure. You don't make a physical volume by "marking" it as such in the same way you don't make a filesystem by "marking" it - it needs formatting
– Torin
Feb 24 at 16:29
1
pvcreatewrites a header block. This may effectively make the data structures (eg the filesystem superblock) unreadable, but the underlying data may be recoverable by a data recovery tool, or bydd. From a typical end-user perspective, doingpvcreateon a block device may render the existing filesystem unreadable.
– Stephen Harris
Feb 24 at 16:35
add a comment |
1
What do you mean by "mark the disk as a PV"? Formatting an existing device as a PV will effectively lose said data in the same way that reformating a filesystem with a new filesystem will lose previous files.
– Torin
Feb 24 at 16:05
What do you mean? Marking a device as a PV is not reformating a filesystem with a new filesystem.
– Tim
Feb 24 at 16:24
Both involve removing the structure of a volume and replacing it with a new structure. You don't make a physical volume by "marking" it as such in the same way you don't make a filesystem by "marking" it - it needs formatting
– Torin
Feb 24 at 16:29
1
pvcreatewrites a header block. This may effectively make the data structures (eg the filesystem superblock) unreadable, but the underlying data may be recoverable by a data recovery tool, or bydd. From a typical end-user perspective, doingpvcreateon a block device may render the existing filesystem unreadable.
– Stephen Harris
Feb 24 at 16:35
1
1
What do you mean by "mark the disk as a PV"? Formatting an existing device as a PV will effectively lose said data in the same way that reformating a filesystem with a new filesystem will lose previous files.
– Torin
Feb 24 at 16:05
What do you mean by "mark the disk as a PV"? Formatting an existing device as a PV will effectively lose said data in the same way that reformating a filesystem with a new filesystem will lose previous files.
– Torin
Feb 24 at 16:05
What do you mean? Marking a device as a PV is not reformating a filesystem with a new filesystem.
– Tim
Feb 24 at 16:24
What do you mean? Marking a device as a PV is not reformating a filesystem with a new filesystem.
– Tim
Feb 24 at 16:24
Both involve removing the structure of a volume and replacing it with a new structure. You don't make a physical volume by "marking" it as such in the same way you don't make a filesystem by "marking" it - it needs formatting
– Torin
Feb 24 at 16:29
Both involve removing the structure of a volume and replacing it with a new structure. You don't make a physical volume by "marking" it as such in the same way you don't make a filesystem by "marking" it - it needs formatting
– Torin
Feb 24 at 16:29
1
1
pvcreate writes a header block. This may effectively make the data structures (eg the filesystem superblock) unreadable, but the underlying data may be recoverable by a data recovery tool, or by dd. From a typical end-user perspective, doing pvcreate on a block device may render the existing filesystem unreadable.– Stephen Harris
Feb 24 at 16:35
pvcreate writes a header block. This may effectively make the data structures (eg the filesystem superblock) unreadable, but the underlying data may be recoverable by a data recovery tool, or by dd. From a typical end-user perspective, doing pvcreate on a block device may render the existing filesystem unreadable.– Stephen Harris
Feb 24 at 16:35
add a comment |
1 Answer
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Does it say that pvcreate will destroy all the data on a disk,
No, I read all the quotes in your question, and it does not say this.
Never pvcreate, not mkfs, will securely delete a partition. They do not write to much of the partition. They only write what they need to, the rest is ignored.
When the OS reads this partition, it will see what type it is, and only follow links to initialised data, the rest with old stuff will be ignored. However if you choose to read it in a different way (forensic analysis), then you can see much of what was there before).
However
While we can not trust them to remove data, we also cannot trust them not to write over data. They write what they need to, this could over-right important data.
Is there a way to convert from one file-system/PV to another?
I don't know. It depends what you are converting to what.
answered Feb 24 at 16:44
ctrl-alt-delorctrl-alt-delor
12k42360
add a comment |
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Does it say that pvcreate will destroy all the data on a disk,
No, I read all the quotes in your question, and it does not say this.
Never pvcreate, not mkfs, will securely delete a partition. They do not write to much of the partition. They only write what they need to, the rest is ignored.
When the OS reads this partition, it will see what type it is, and only follow links to initialised data, the rest with old stuff will be ignored. However if you choose to read it in a different way (forensic analysis), then you can see much of what was there before).
However
While we can not trust them to remove data, we also cannot trust them not to write over data. They write what they need to, this could over-right important data.
Is there a way to convert from one file-system/PV to another?
I don't know. It depends what you are converting to what.
answered Feb 24 at 16:44
ctrl-alt-delorctrl-alt-delor
12k42360
add a comment |
Does it say that pvcreate will destroy all the data on a disk,
No, I read all the quotes in your question, and it does not say this.
Never pvcreate, not mkfs, will securely delete a partition. They do not write to much of the partition. They only write what they need to, the rest is ignored.
When the OS reads this partition, it will see what type it is, and only follow links to initialised data, the rest with old stuff will be ignored. However if you choose to read it in a different way (forensic analysis), then you can see much of what was there before).
However
While we can not trust them to remove data, we also cannot trust them not to write over data. They write what they need to, this could over-right important data.
Is there a way to convert from one file-system/PV to another?
I don't know. It depends what you are converting to what.
answered Feb 24 at 16:44
ctrl-alt-delorctrl-alt-delor
12k42360
add a comment |
Does it say that pvcreate will destroy all the data on a disk,
No, I read all the quotes in your question, and it does not say this.
Never pvcreate, not mkfs, will securely delete a partition. They do not write to much of the partition. They only write what they need to, the rest is ignored.
When the OS reads this partition, it will see what type it is, and only follow links to initialised data, the rest with old stuff will be ignored. However if you choose to read it in a different way (forensic analysis), then you can see much of what was there before).
However
While we can not trust them to remove data, we also cannot trust them not to write over data. They write what they need to, this could over-right important data.
Is there a way to convert from one file-system/PV to another?
I don't know. It depends what you are converting to what.
answered Feb 24 at 16:44
ctrl-alt-delorctrl-alt-delor
12k42360
Does it say that pvcreate will destroy all the data on a disk,
No, I read all the quotes in your question, and it does not say this.
Never pvcreate, not mkfs, will securely delete a partition. They do not write to much of the partition. They only write what they need to, the rest is ignored.
When the OS reads this partition, it will see what type it is, and only follow links to initialised data, the rest with old stuff will be ignored. However if you choose to read it in a different way (forensic analysis), then you can see much of what was there before).
However
While we can not trust them to remove data, we also cannot trust them not to write over data. They write what they need to, this could over-right important data.
Is there a way to convert from one file-system/PV to another?
I don't know. It depends what you are converting to what.
answered Feb 24 at 16:44
ctrl-alt-delorctrl-alt-delor
12k42360
answered Feb 24 at 16:44
ctrl-alt-delorctrl-alt-delor
12k42360
answered Feb 24 at 16:44
ctrl-alt-delorctrl-alt-delor
12k42360
answered Feb 24 at 16:44
ctrl-alt-delorctrl-alt-delor
12k42360
12k42360
add a comment |
add a comment |
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1
What do you mean by "mark the disk as a PV"? Formatting an existing device as a PV will effectively lose said data in the same way that reformating a filesystem with a new filesystem will lose previous files.
– Torin
Feb 24 at 16:05
What do you mean? Marking a device as a PV is not reformating a filesystem with a new filesystem.
– Tim
Feb 24 at 16:24
Both involve removing the structure of a volume and replacing it with a new structure. You don't make a physical volume by "marking" it as such in the same way you don't make a filesystem by "marking" it - it needs formatting
– Torin
Feb 24 at 16:29
1
pvcreatewrites a header block. This may effectively make the data structures (eg the filesystem superblock) unreadable, but the underlying data may be recoverable by a data recovery tool, or bydd. From a typical end-user perspective, doingpvcreateon a block device may render the existing filesystem unreadable.– Stephen Harris
Feb 24 at 16:35