Re: [CentOS] Utility to zero unused blocks on disk

On Tue, February 9, 2016 16:05, Chris Murphy wrote: > On Mon, Feb 8, 2016 at 11:18 PM, John R Pierce > wrote: >> On 2/8/2016 9:54 PM, Chris Murphy wrote: >>> >>> Secure erase is really the only thing to use on SSDs. >>> Writing a pile of zeros just increases wear (minor

Re: [CentOS] Utility to zero unused blocks on disk

On 02/08/2016 07:38 PM, Always Learning wrote: On Mon, 2016-02-08 at 14:22 -0800, John R Pierce wrote: the only truly safe way to destroy data on magnetic media is to grind the media up into filings or melt it down in a furnace. I unscrew the casing, extract the disk platter(s), slide a

Re: [CentOS] Utility to zero unused blocks on disk

On 2/9/2016 12:42 AM, g wrote: On 02/08/16 23:39, Digimer wrote: > >I need ice cream to feel better.;) > . Baskin-Robbins 32 flavors + special of month. After seeing Aaron Neville tonight (wow, what a show, 3rd row center seats in a small theater, we were 15' from the stage), we stopped at

Re: [CentOS] Utility to zero unused blocks on disk

On 02/08/16 23:54, Chris Murphy wrote: <<>> > hdparm --user-master u --set-security-pass chickens /dev/sdX centos 6.7, hdparm v- 9.43; hdparm --user-master u --security-set-pass chickens /dev/sdX -- peace out. If Bill Gates got a dime for every time Windows crashes... ...oh, wait. He

Re: [CentOS] Utility to zero unused blocks on disk

On 02/08/16 23:39, Digimer wrote: > On 09/02/16 12:24 AM, g wrote: <<>> >> fell better? :-P > > I need ice cream to feel better. ;) > . Baskin-Robbins 32 flavors + special of month. -- peace out. If Bill Gates got a dime for every time Windows crashes... ...oh, wait. He does. THAT explains

Re: [CentOS] Utility to zero unused blocks on disk

> -Original Message- > From: centos-boun...@centos.org [mailto:centos-boun...@centos.org] On > Behalf Of EGO-II.1 > Sent: den 9 februari 2016 09:00 > To: CentOS mailing list > Subject: Re: [CentOS] Utility to zero unused blocks on disk > > > > >> the

Re: [CentOS] Utility to zero unused blocks on disk

On 02/08/2016 07:38 PM, Always Learning wrote: I unscrew the casing, extract the disk platter(s), slide a very strong magnet over both sides of the platter surface then bend the platter in half. How secure is that ? Actually, while there is some good security to that it's not for the reason

Re: [CentOS] Utility to zero unused blocks on disk

On 02/09/16 02:51, John R Pierce wrote: > On 2/9/2016 12:42 AM, g wrote: >> On 02/08/16 23:39, Digimer wrote: >>> >>> I need ice cream to feel better.;) >>> >> . >> Baskin-Robbins 32 flavors + special of month. > > After seeing Aaron Neville tonight (wow, what a show, 3rd row center > seats in

Re: [CentOS] Utility to zero unused blocks on disk

On Mon, Feb 8, 2016 at 11:18 PM, John R Pierce wrote: > On 2/8/2016 9:54 PM, Chris Murphy wrote: >> >> Secure erase is really the only thing to use on SSDs. Writing a pile >> of zeros just increases wear (minor negative) but also doesn't >> actually set the cells to the state

Re: [CentOS] Utility to zero unused blocks on disk

gt;> [CentOS] Utility to zero unused blocks on disk >> >> >> >>>> the only truly safe way to destroy data on magnetic media is >>>> to grind the media up into filings or melt it down in a >>>> furnace. >>> I unscrew the casing, ext

Re: [CentOS] Utility to zero unused blocks on disk

On 09/02/16 12:24 AM, g wrote: > > > On 02/08/16 23:10, Digimer wrote: >> On 09/02/16 12:08 AM, g wrote: >>> >>> >>> On 02/08/16 15:34, Wes James wrote: Is there a utility to zero unused blocks on a disk? CentOS 6.7/Ext4 I saw zerofree, but I’m not sure it would work on

Re: [CentOS] Utility to zero unused blocks on disk

On Mon, Feb 8, 2016 at 10:54 PM, Chris Murphy wrote: > Secure erase is really the only thing to use on SSDs. Oops. It's probably a fairly close approximation to just mkfs.btrfs -f (or xfs) the entire block device for the SSD. If the kernel sees it as non-rotational,

Re: [CentOS] Utility to zero unused blocks on disk

On 02/08/16 15:34, Wes James wrote: > Is there a utility to zero unused blocks on a disk? > > CentOS 6.7/Ext4 > > I saw zerofree, but I’m not sure it would work on Ext4 or even work on > this version of CentOS. > > thanks, > . a comment on replies to your post. i find it interesting that

Re: [CentOS] Utility to zero unused blocks on disk

On 09/02/16 12:08 AM, g wrote: > > > On 02/08/16 15:34, Wes James wrote: >> Is there a utility to zero unused blocks on a disk? >> >> CentOS 6.7/Ext4 >> >> I saw zerofree, but I’m not sure it would work on Ext4 or even work on >> this version of CentOS. >> >> thanks, >> > . > a comment on

Re: [CentOS] Utility to zero unused blocks on disk

On 02/08/16 23:10, Digimer wrote: > On 09/02/16 12:08 AM, g wrote: >> >> >> On 02/08/16 15:34, Wes James wrote: >>> Is there a utility to zero unused blocks on a disk? >>> >>> CentOS 6.7/Ext4 >>> >>> I saw zerofree, but I’m not sure it would work on Ext4 or even work on >>> this version of

Re: [CentOS] Utility to zero unused blocks on disk

On Mon, Feb 8, 2016 at 3:18 PM, wrote: > Chris Murphy wrote: >> DBAN is obsolete. NIST 800-88 for some time now says to use secure erase >> or enhanced security erase or crypto erase if supported. >> >> Other options do not erase data in remapped sectors. > > dban doesn't? What

Re: [CentOS] Utility to zero unused blocks on disk

On 02/08/2016 07:04 PM, Chris Adams wrote: Once upon a time, Greg Bailey said: Wes didn't say the reason he wanted to zero unused blocks, but I always do this in kickstart scripts when constructing VM images as the image size is considerably reduced by doing this... For

Re: [CentOS] Utility to zero unused blocks on disk

Once upon a time, Robert Nichols said: > On 02/08/2016 07:04 PM, Chris Adams wrote: > >For that purpose, use something that can TRIM a VM image, like > >virt-sparsify. > > That's doing the same thing. > > virt-sparsify works by mounting the filesystem, filling it to

Re: [CentOS] Utility to zero unused blocks on disk

On 2/8/2016 9:54 PM, Chris Murphy wrote: Secure erase is really the only thing to use on SSDs. Writing a pile of zeros just increases wear (minor negative) but also doesn't actually set the cells to the state required to accept a new write, so you've just added a lot more work for the SSD's

[CentOS] Utility to zero unused blocks on disk

Is there a utility to zero unused blocks on a disk? CentOS 6.7/Ext4 I saw zerofree, but I’m not sure it would work on Ext4 or even work on this version of CentOS. thanks, -wes ___ CentOS mailing list CentOS@centos.org

Re: [CentOS] Utility to zero unused blocks on disk

Personally, I just do 'dd if=/dev/zero of=/path/to/zero.img bs=1M; rm -f /path/to/zero.img'. It's inelegant, for sure, but it works (note to run it as a normal user or else be careful of how your system reacts to running out of disk space for a moment). fix-it-with-a-hammer-digimer On 08/02/16

Re: [CentOS] Utility to zero unused blocks on disk

hdparm supports ATA secure erase. This is SSD safe, unlike other options. It's faster than writing zeros to both HDD and SSD. Chris Murphy On Mon, Feb 8, 2016, 3:06 PM wrote: > Wes James wrote: > > Is there a utility to zero unused blocks on a disk? > > > > CentOS 6.7/Ext4 >

Re: [CentOS] Utility to zero unused blocks on disk

DBAN is obsolete. NIST 800-88 for some time now says to use secure erase or enhanced security erase or crypto erase if supported. Other options do not erase data in remapped sectors. Chris Murphy ___ CentOS mailing list CentOS@centos.org

Re: [CentOS] Utility to zero unused blocks on disk

John R Pierce wrote: > On 2/8/2016 2:14 PM, Chris Murphy wrote: >> DBAN is obsolete. NIST 800-88 for some time now says to use secure erase >> or >> enhanced security erase or crypto erase if supported. >> >> Other options do not erase data in remapped sectors. > > the only truly safe way to

Re: [CentOS] Utility to zero unused blocks on disk

Wes James wrote: > Is there a utility to zero unused blocks on a disk? > > CentOS 6.7/Ext4 > > I saw zerofree, but I’m not sure it would work on Ext4 or even work on > this version of CentOS. > I don't understand the point of doing this. If you want to sanitize the disk, use dban , which surely

Re: [CentOS] Utility to zero unused blocks on disk

On 02/08/2016 03:05 PM, m.r...@5-cent.us wrote: Wes James wrote: Is there a utility to zero unused blocks on a disk? CentOS 6.7/Ext4 I saw zerofree, but I’m not sure it would work on Ext4 or even work on this version of CentOS. I don't understand the point of doing this. Wes didn't say

Re: [CentOS] Utility to zero unused blocks on disk

> On Feb 8, 2016, at 2:37 PM, Digimer wrote: > > Personally, I just do 'dd if=/dev/zero of=/path/to/zero.img bs=1M; rm -f > /path/to/zero.img'. It's inelegant, for sure, but it works (note to run > it as a normal user or else be careful of how your system reacts to > running

Re: [CentOS] Utility to zero unused blocks on disk

Chris Murphy wrote: > DBAN is obsolete. NIST 800-88 for some time now says to use secure erase > or enhanced security erase or crypto erase if supported. > > Other options do not erase data in remapped sectors. dban doesn't? What F/OSS does "secure erase"? And does it do what dban's DoD 5220.22-M

Re: [CentOS] Utility to zero unused blocks on disk

On 2/8/2016 2:14 PM, Chris Murphy wrote: DBAN is obsolete. NIST 800-88 for some time now says to use secure erase or enhanced security erase or crypto erase if supported. Other options do not erase data in remapped sectors. the only truly safe way to destroy data on magnetic media is to grind

Re: [CentOS] Utility to zero unused blocks on disk

On 2/8/2016 2:18 PM, m.r...@5-cent.us wrote: dban doesn't? What F/OSS does "secure erase"? And does it do what dban's DoD 5220.22-M does? do you even know what NISP Operating Manual 5220.22-M is? One thing it does NOT have is ANY specifications of methods of data erasure (it mentions data

Re: [CentOS] Utility to zero unused blocks on disk

On Mon, February 8, 2016 5:45 pm, John R Pierce wrote: > On 2/8/2016 3:33 PM, Valeri Galtsev wrote: >> DRAM had more persistent imprint of information that was sitting in it, >> which appears much harder to destroy than information on hard drive. > > well aware of that. 30 years ago a friend

Re: [CentOS] Utility to zero unused blocks on disk

On Mon, 2016-02-08 at 14:22 -0800, John R Pierce wrote: > the only truly safe way to destroy data on magnetic media is to grind > the media up into filings or melt it down in a furnace. I unscrew the casing, extract the disk platter(s), slide a very strong magnet over both sides of the platter

Re: [CentOS] Utility to zero unused blocks on disk

On 02/08/2016 06:38 PM, Always Learning wrote: > > On Mon, 2016-02-08 at 14:22 -0800, John R Pierce wrote: > >> the only truly safe way to destroy data on magnetic media is to grind >> the media up into filings or melt it down in a furnace. > > I unscrew the casing, extract the disk

Re: [CentOS] Utility to zero unused blocks on disk

On Mon, February 8, 2016 4:22 pm, John R Pierce wrote: > On 2/8/2016 2:14 PM, Chris Murphy wrote: >> DBAN is obsolete. NIST 800-88 for some time now says to use secure erase >> or >> enhanced security erase or crypto erase if supported. >> >> Other options do not erase data in remapped sectors. >

Re: [CentOS] Utility to zero unused blocks on disk

On Mon, February 8, 2016 3:37 pm, Digimer wrote: > Personally, I just do 'dd if=/dev/zero of=/path/to/zero.img bs=1M; rm -f > /path/to/zero.img'. It's inelegant, for sure, but it works (note to run > it as a normal user or else be careful of how your system reacts to > running out of disk space

Re: [CentOS] Utility to zero unused blocks on disk

On 2/8/2016 3:33 PM, Valeri Galtsev wrote: DRAM had more persistent imprint of information that was sitting in it, which appears much harder to destroy than information on hard drive. well aware of that. 30 years ago a friend and I built a specialized video card for a consulting project

Re: [CentOS] Utility to zero unused blocks on disk

Once upon a time, Greg Bailey said: > Wes didn't say the reason he wanted to zero unused blocks, but I > always do this in kickstart scripts when constructing VM images as > the image size is considerably reduced by doing this... For that purpose, use something that can TRIM a