Difference between revisions of "Solid State Drives/Memory cell clearing"

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(Introduction)
(Step 1 - Make sure the drive security is not frozen)
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[[Category: Storage (English)]]
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[[Category:Storage]]
 
{{Article summary start}}
 
{{Article summary start}}
 
{{Article summary text|This article presents a method to reset all cells on an SSD to their factory default state thus recovering any loss of write performance.}}
 
{{Article summary text|This article presents a method to reset all cells on an SSD to their factory default state thus recovering any loss of write performance.}}
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== Introduction ==
 
== Introduction ==
  
On occasion, users may wish to completely reset an SSD's cells to the same virgin state they were at the time he/she installed the device thus restoring it to its [http://www.anandtech.com/storage/showdoc.aspx?i=3531&p=8 factory default write performance]. Write performance is known to degrade over time even on SSDs with native TRIM support. TRIM only safeguards against file deletes, not replacements such as an incremental save.
+
On occasion, users may wish to completely reset an SSD's cells to the same virgin state they were manufactured, thus restoring it to its [http://www.anandtech.com/storage/showdoc.aspx?i=3531&p=8 factory default write performance]. Write performance is known to degrade over time even on SSDs with native TRIM support. TRIM only safeguards against file deletes, not replacements such as an incremental save.
{{Warning|Back up ALL data of importance prior to continuing! Using this procedure will destroy ALL data on the SSD and render it unrecoverable by even data recovery services! Users will have to repartition the device and restore the data after completing this procedure!}}
+
{{Warning|Back up ALL data of importance prior to continuing! Using this procedure will destroy ALL data on the SSD and render it unrecoverable by even data recovery services! Users will have to repartition the device and restore the data after completing this procedure!}}
 +
 
 +
== tl; dr ==
 +
 
 +
{{Warning|It is recommended that you read the rest of the article BEFORE you try this!}}
 +
 +
dcfldd if=/dev/zero of=/dev/sdX bs=4m
 +
hdparm --user-master u --security-set-pass Eins /dev/sdX
 +
hdparm --user-master u --security-erase Eins /dev/sdX
 +
 
 +
== Step 0 ==
 +
{{warning|Triple check that the correct drive designation is used in the dcfldd step; '''THERE IS NO TURNING BACK ONCE THE ENTER KEY HAS BEEN PRESSED!''' You have been warned.}}
 +
 
 +
Optionally write zeros to every block on the SSD using either {{ic|dd}} or {{ic|dcfldd}}:
 +
  dcfldd if=/dev/zero of=/dev/sdX bs=4m
 +
 
 +
Depending on the size and speed of the SSD, this step may take some time. A very nice feature of {{ic|dcfldd}} is the level of verbosity it uses by default. It will report the current amount of data written to the device. Users can approximate how long the process will take based on this output.
  
 
== Step 1 - Make sure the drive security is not frozen ==
 
== Step 1 - Make sure the drive security is not frozen ==
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  # hdparm -I /dev/sdX
 
  # hdparm -I /dev/sdX
  
If the command output shows "frozen" one cannot continue to the next step. Most BIOSes block (do no allow) the ATA Secure Erase command by issuing a "SECURITY FREEZE" command to "freeze" the drive before booting an operating system.
+
If the command output shows "frozen" one cannot continue to the next step. Most BIOSes block the ATA Secure Erase command by issuing a "SECURITY FREEZE" command to "freeze" the drive before booting an operating system.
  
A possible solution for SATA drives is hot-(re)plug the data cable (which might crash the kernel). If hot-(re)pluging the SATA data cable crashes the kernel try letting the operating system fully boot up, then quickly hot-(re)plug both the SATA power and data cables.
+
A possible solution for SATA drives is hot-(re)plug the data cable (which might crash the kernel). If hot-(re)plugging the SATA data cable crashes the kernel try letting the operating system fully boot up, then quickly hot-(re)plug both the SATA power and data cables.
  
* It has been reported that hooking up the drive to an eSATA SIIG ExpressCard/54 with an eSATA enclosure will leave the drive security state to "not frozen."
+
* It has been reported that hooking up the drive to an eSATA SIIG ExpressCard/54 with an eSATA enclosure will leave the drive security state to "not frozen".
* Placing the target system into "sleep" (Clevo M865TU notebook) has reported to work as well; this may reset other drives to "not frozen."
+
* Placing the target system into "sleep" (Clevo M865TU notebook, Fujitsu T2010 notebook, Dell XPS M1330, Lenovo ThinkPad x220/x230, Samsung NC10) and waking it up again has been reported to work as well; this may reset drives to "not frozen". In case you are booting from USB, you need a distribution, that runs entirely in RAM, like [http://grml.org Grml], see the {{ic|grml2ram}} option. Run {{ic|echo -n mem > /sys/power/state}} to set the computer to sleep.
 +
* Hooking up the drive to a USB 2/3 port does '''NOT''' work, as you need to issue IDE commands, which is only possible via IDE/SATA connection.
 +
* Make sure drive security is '''disabled''' in BIOS, so no password is set:
  
 
<pre>Security:  
 
<pre>Security:  
Line 34: Line 52:
  
 
== Step 2 - Enable security by setting a user password ==
 
== Step 2 - Enable security by setting a user password ==
{{Note|When the user password is set the drive will be locked after next power cycle denying normal access until unlocked with the correct password).}}
+
{{Note|When the user password is set the drive will be locked after next power cycle denying normal access until unlocked with the correct password.}}
   
+
 
Any password will do, as this should only be temporary. After the secure erase the password will be set back to NULL. In this example, the password is "Eins" as shown:
+
Any password will do, as this should only be temporary. After the secure erase the password will be set back to NULL. In this example, the password is "Eins" as shown:
 
  # hdparm --user-master u --security-set-pass Eins /dev/sdX
 
  # hdparm --user-master u --security-set-pass Eins /dev/sdX
 
  security_password="Eins"
 
  security_password="Eins"
Line 62: Line 80:
 
  # time hdparm --user-master u --security-erase Eins /dev/sdX
 
  # time hdparm --user-master u --security-erase Eins /dev/sdX
  
Wait until the command completes. This example output shows it took about 40 seconds for an Intel X25-M 80GB SSD, for a 1TB hard disk it might take 3 hours or more!
+
Wait until the command completes. This example output shows it took about 40 seconds for an Intel X25-M 80GB SSD (for a 1TB hard disk it could take up to 3 hours).
  
 
  security_password="Eins"
 
  security_password="Eins"
Line 69: Line 87:
 
  0.000u 0.000s 0:39.71 0.0%      0+0k 0+0io 0pf+0w
 
  0.000u 0.000s 0:39.71 0.0%      0+0k 0+0io 0pf+0w
  
The drive is now erased. After a successful erasure the drive security should automatically be set to disabled (thus no longer requiring a password for access). Verify this by running the following command:
+
The drive is now erased. After a successful erasure the drive security should automatically be set to disabled (thus no longer requiring a password for access). Verify this by running the following command:
 
  # hdparm -I /dev/sdX
 
  # hdparm -I /dev/sdX
  
Line 82: Line 100:
 
                 supported: enhanced erase
 
                 supported: enhanced erase
 
         2min for SECURITY ERASE UNIT. 2min for ENHANCED SECURITY ERASE UNIT.</pre>
 
         2min for SECURITY ERASE UNIT. 2min for ENHANCED SECURITY ERASE UNIT.</pre>
 +
 +
== Tips ==
 +
See the [[GRUB_EFI_Examples]] for hardware-specific instructions to get GRUB EFI working following a wipe.

Revision as of 06:36, 4 March 2013

Template:Article summary start Template:Article summary text Template:Article summary heading Template:Article summary wiki Template:Article summary wiki Template:Article summary end

Introduction

On occasion, users may wish to completely reset an SSD's cells to the same virgin state they were manufactured, thus restoring it to its factory default write performance. Write performance is known to degrade over time even on SSDs with native TRIM support. TRIM only safeguards against file deletes, not replacements such as an incremental save.

Warning: Back up ALL data of importance prior to continuing! Using this procedure will destroy ALL data on the SSD and render it unrecoverable by even data recovery services! Users will have to repartition the device and restore the data after completing this procedure!

tl; dr

Warning: It is recommended that you read the rest of the article BEFORE you try this!
dcfldd if=/dev/zero of=/dev/sdX bs=4m
hdparm --user-master u --security-set-pass Eins /dev/sdX
hdparm --user-master u --security-erase Eins /dev/sdX

Step 0

Warning: Triple check that the correct drive designation is used in the dcfldd step; THERE IS NO TURNING BACK ONCE THE ENTER KEY HAS BEEN PRESSED! You have been warned.

Optionally write zeros to every block on the SSD using either dd or dcfldd:

 dcfldd if=/dev/zero of=/dev/sdX bs=4m

Depending on the size and speed of the SSD, this step may take some time. A very nice feature of dcfldd is the level of verbosity it uses by default. It will report the current amount of data written to the device. Users can approximate how long the process will take based on this output.

Step 1 - Make sure the drive security is not frozen

Issue the following command:

# hdparm -I /dev/sdX

If the command output shows "frozen" one cannot continue to the next step. Most BIOSes block the ATA Secure Erase command by issuing a "SECURITY FREEZE" command to "freeze" the drive before booting an operating system.

A possible solution for SATA drives is hot-(re)plug the data cable (which might crash the kernel). If hot-(re)plugging the SATA data cable crashes the kernel try letting the operating system fully boot up, then quickly hot-(re)plug both the SATA power and data cables.

  • It has been reported that hooking up the drive to an eSATA SIIG ExpressCard/54 with an eSATA enclosure will leave the drive security state to "not frozen".
  • Placing the target system into "sleep" (Clevo M865TU notebook, Fujitsu T2010 notebook, Dell XPS M1330, Lenovo ThinkPad x220/x230, Samsung NC10) and waking it up again has been reported to work as well; this may reset drives to "not frozen". In case you are booting from USB, you need a distribution, that runs entirely in RAM, like Grml, see the grml2ram option. Run echo -n mem > /sys/power/state to set the computer to sleep.
  • Hooking up the drive to a USB 2/3 port does NOT work, as you need to issue IDE commands, which is only possible via IDE/SATA connection.
  • Make sure drive security is disabled in BIOS, so no password is set:
Security: 
        Master password revision code = 65534
                supported
        not     enabled
        not     locked
        not     frozen
        not     expired: security count
                supported: enhanced erase
        2min for SECURITY ERASE UNIT. 2min for ENHANCED SECURITY ERASE UNIT.

Step 2 - Enable security by setting a user password

Note: When the user password is set the drive will be locked after next power cycle denying normal access until unlocked with the correct password.

Any password will do, as this should only be temporary. After the secure erase the password will be set back to NULL. In this example, the password is "Eins" as shown:

# hdparm --user-master u --security-set-pass Eins /dev/sdX
security_password="Eins"
/dev/sdX:
Issuing SECURITY_SET_PASS command, password="Eins", user=user, mode=high

As a sanity check, issue the following command

# hdparm -I /dev/sdX

The command output should display "enabled":

 Security: 
        Master password revision code = 65534
                supported
                enabled
        not     locked
        not     frozen
        not     expired: security count
                supported: enhanced erase
        Security level high
        2min for SECURITY ERASE UNIT. 2min for ENHANCED SECURITY ERASE UNIT.

Step 3 - Issue the ATA Secure Erase command

# time hdparm --user-master u --security-erase Eins /dev/sdX

Wait until the command completes. This example output shows it took about 40 seconds for an Intel X25-M 80GB SSD (for a 1TB hard disk it could take up to 3 hours).

security_password="Eins"
/dev/sdX:
Issuing SECURITY_ERASE command, password="Eins", user=user
0.000u 0.000s 0:39.71 0.0%      0+0k 0+0io 0pf+0w

The drive is now erased. After a successful erasure the drive security should automatically be set to disabled (thus no longer requiring a password for access). Verify this by running the following command:

# hdparm -I /dev/sdX

The command output should display "not enabled":

 Security: 
        Master password revision code = 65534
                supported
        not     enabled
        not     locked
        not     frozen
        not     expired: security count
                supported: enhanced erase
        2min for SECURITY ERASE UNIT. 2min for ENHANCED SECURITY ERASE UNIT.

Tips

See the GRUB_EFI_Examples for hardware-specific instructions to get GRUB EFI working following a wipe.