Re: [CentOS] erasing a disk
At 01:34 PM 9/14/2020, you wrote: 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-sectors-on-the-hard-disk/ Also, use wipefs -a (Gordon Messmer answered faster than me) On Mon, Sep 14, 2020 at 3:18 PM david 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 blocks starting at block >- erase last 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 > Thanks for the suggestion. "wipefs" looks like the right answer. David ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] erasing a disk
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 ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] erasing a disk
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 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 ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] erasing a disk
On 2020-09-14 16:52, Robert Heller wrote: At Mon, 14 Sep 2020 13:14:44 -0700 CentOS mailing list 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. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] erasing a disk
At Mon, 14 Sep 2020 13:14:44 -0700 CentOS mailing list 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 blocks starting at block >- erase last 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 > > > > -- Robert Heller -- Cell: 413-658-7953 GV: 978-633-5364 Deepwoods Software-- Custom Software Services http://www.deepsoft.com/ -- Linux Administration Services hel...@deepsoft.com -- Webhosting Services ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] erasing a disk
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-sectors-on-the-hard-disk/ Also, use wipefs -a (Gordon Messmer answered faster than me) On Mon, Sep 14, 2020 at 3:18 PM david 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 blocks starting at block >- erase last 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 > -- - Erick Perez Quadrian Enterprises S.A. - Panama, Republica de Panama Skype chat: eaperezh WhatsApp IM: +507-6675-5083 - ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] erasing a disk
On Mon, Sep 14, 2020 at 3:18 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? > 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. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] erasing a disk
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. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
[CentOS] erasing a disk
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 blocks starting at block - erase last 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
