Folks
I've encountered situations where I want to reuse a hard-drive. I do not want to preserve anything on the drive, and I'm not concerned about 'securely erasing' old content. I just want to be able to define it as an Physical Volume (in a logical volume set), or make it a ZFS disk, or sometimes make it a simple EXT3, ExFAT or NTFS disk. However, old 'signatures' get in the way and Linux sometimes refuses to let me proceed. I know that a fool-proof solution is to use the "dd if=/dev/zero bs=32768 oflag=direct" on the disk, but when we're talking USB-connected hard drives of 8 TB, that's an operation that can take days.
The disk in question might even have been corrupted. This would make using 'zpool destroy' to clear out a ZFS disk, or
I've tried erasing the first megabyte of the disk, but there are ZFS or LVM structures that get in the way. So, does anyone have an efficient way to erase structures from a disk such that it can be reused?
Something like -erase first N blocks (block defined as 4096) - Erase <number> blocks starting at block <number> - erase last <number> blocks
At least such an algorithm would be quicker than erasing 8 TB of data.
David
On 9/14/20 1:14 PM, david wrote:
I've tried erasing the first megabyte of the disk, but there are ZFS or LVM structures that get in the way. So, does anyone have an efficient way to erase structures from a disk such that it can be reused?
Use "wipefs -a" on any partition (or raw disk) before reusing it.
On Mon, Sep 14, 2020 at 3:18 PM david david@daku.org wrote:
I've tried erasing the first megabyte of the disk, but there are ZFS or LVM structures that get in the way. So, does anyone have an efficient way to erase structures from a disk such that it can be reused?
GPT for sure has backup metadata on the drive, so you won't be wiping it by trying to remove the first few MB. You always should try using tooling made for the purpose instead of trying to manually do it. In this case try a tool like wipefs.
what if you just dd the first 1GB of the disk and the last GB of the disk (the last because of RAID signatures of some controllers that write to the end of the disk) Look at this article and modify accordingly https://zedt.eu/tech/linux/using-dd-to-repeatedly-erase-a-specific-range-of-...
Also, use wipefs -a (Gordon Messmer answered faster than me)
On Mon, Sep 14, 2020 at 3:18 PM david david@daku.org wrote:
Folks
I've encountered situations where I want to reuse a hard-drive. I do not want to preserve anything on the drive, and I'm not concerned about 'securely erasing' old content. I just want to be able to define it as an Physical Volume (in a logical volume set), or make it a ZFS disk, or sometimes make it a simple EXT3, ExFAT or NTFS disk. However, old 'signatures' get in the way and Linux sometimes refuses to let me proceed. I know that a fool-proof solution is to use the "dd if=/dev/zero bs=32768 oflag=direct" on the disk, but when we're talking USB-connected hard drives of 8 TB, that's an operation that can take days.
The disk in question might even have been corrupted. This would make using 'zpool destroy' to clear out a ZFS disk, or
I've tried erasing the first megabyte of the disk, but there are ZFS or LVM structures that get in the way. So, does anyone have an efficient way to erase structures from a disk such that it can be reused?
Something like -erase first N blocks (block defined as 4096)
- Erase <number> blocks starting at block <number>
- erase last <number> blocks
At least such an algorithm would be quicker than erasing 8 TB of data.
David
CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
At Mon, 14 Sep 2020 13:14:44 -0700 CentOS mailing list centos@centos.org wrote:
Folks
I've encountered situations where I want to reuse a hard-drive. I do not want to preserve anything on the drive, and I'm not concerned about 'securely erasing' old content. I just want to be able to define it as an Physical Volume (in a logical volume set), or make it a ZFS disk, or sometimes make it a simple EXT3, ExFAT or NTFS disk. However, old 'signatures' get in the way and Linux sometimes refuses to let me proceed. I know that a fool-proof solution is to use the "dd if=/dev/zero bs=32768 oflag=direct" on the disk, but when we're talking USB-connected hard drives of 8 TB, that's an operation that can take days.
The disk in question might even have been corrupted. This would make using 'zpool destroy' to clear out a ZFS disk, or
I've tried erasing the first megabyte of the disk, but there are ZFS or LVM structures that get in the way. So, does anyone have an efficient way to erase structures from a disk such that it can be reused?
Something like -erase first N blocks (block defined as 4096)
- Erase <number> blocks starting at block <number>
- erase last <number> blocks
Use dd in a script:
#!/bin/bash # erase N 4K blocks starting at M # (M=0 means from the start of the disk) # usage: $0 start4Kblock numberof4Kblocks drive M = $1 N = $2 rawdisk = $3 dd if=/dev/zero bs=4096 oflag=direct count=$N seek=$M of=$rawdisk
At least such an algorithm would be quicker than erasing 8 TB of data.
David
CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
On 2020-09-14 16:52, Robert Heller wrote:
At Mon, 14 Sep 2020 13:14:44 -0700 CentOS mailing list centos@centos.org wrote:
Folks
I've encountered situations where I want to reuse a hard-drive. I do
If it is a Seagate, don't bother. They have the highest failure rate in the industry.
Look at the SMART statistics before deciding to re-use a disk, especially "Reallocated_Sector_Ct," "Power_On_Hours," and run the "extended SMART test."
Todd Merriman Software Toolz, Inc.
At 02:36 PM 9/14/2020, you wrote:
On 2020-09-14 16:52, Robert Heller wrote:
At Mon, 14 Sep 2020 13:14:44 -0700 CentOS mailing list centos@centos.org wrote:
Folks I've encountered situations where I want to reuse a hard-drive. I do
If it is a Seagate, don't bother. They have the highest failure rate in the industry.
Look at the SMART statistics before deciding to re-use a disk, especially "Reallocated_Sector_Ct," "Power_On_Hours," and run the "extended SMART test."
Todd Merriman Software Toolz, Inc.
Todd
The reason I'm reusing a disk is not because of hardware failures, but rather because I've abandoned a particular use for that disk, maybe changed operating systems, maybe tried something using ZFS and want to change to some other techonology. I know that the best way to reclaim a disk after read-failures is to wipe it with zeros, and this takes days.
And by the way, I typically use only WD disks, not seagate.
Thanks for the confirmation.
David
I've never run into a system yet where using dd to write zeros on the first few megabytes didn't completely wipe the disk as far as the OS and existing file systems are concerned..
dd if=/dev/zero of=/dev/sde bs=65536 count=1024
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