Wiping free space on SSD - TRIM - Recuva showing folder paths

[ccw62]

Up front, I know, it is written and suggested all over Internet: wiping free space on a SSD is not recommended.

 

Although it is not entirely clear whether the reason is mainly the wear of the SSD or  'wear'  and  other technical reasons.

If it is the wear only, one might argue  that today's quality SSD don't wear out so quickly, so I guess when it comes to wear only,

running 'Wipe Free Space', say, just once a month might not be so harmful..??  (I don't know really)

 

Anyway I learned not to use wipe free space, but TRIM should be used.

Okay.

 

However, when running Recuva deep scan on the SSD, it will display deleted files and folders that one does not want to be displayed.

(TRIM=Activated)

 

Q: How to avoid that then?

 

On normal HDD's, after running wipe free space, the deleted files/folders are displayed by a bunch of Z's which is really perfect.

 

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[Augeas]

On a TRIM-enabled SSD there should be little difference between a normal and deep scan, as a deep scan runs a normal scan first, and the deep scan component should find no, or very few, additional files (TRIM causes the deleted pages to be 'emptied' of all data). If a significant difference is found then a wfs could be run, say once a year or so.

 

The file names you are seeing are in the MFT, which is unaffected by TRIM. Except for small files held entirely within the MFT, the file data has gone. Unfortunately CC does not offer a wipe MFT as a stand-alone feature (I wouldn't expect Recuva to offer it). Some users ger round this by running a wfs from Drive Wiper and then cancelling the job when the wipe MFT has completed, but whether you do this or not is up to you.

[ccw62]

Thank you so much! This is quite new to me, really. So... 'they' say - never run wipe free space on a SSD.

Wiping MFT records would not be so harmful then?

 

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btw - although 'Follow this topic' is tagged, i never get notifications

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[Augeas]

I think it would still be pretty write intensive, although not as much as a complete wfs (which includes a wipe MFT if run from Drive Wiper).

 

A wipe MFT creates enough small files to fill all the unused records in the MFT, and then deletes them, leaving only the ZZZ filenames. On a decent sized and well-used device that could mean many tens of thousands of files to be created. Each file creation will mean a write to a new SSD page of:

 

The MFT record

The MFT bitmap

The root directory

The journal files

Anything else I've not thought of

 

Some of these operations - adding many thousands of files to the root directory for instance - may require multiple pages to be updated.

 

And on file deletion there will be - you've guessed it - exactly the same number of writes to delete the files. I don't know whether some of these writes can be amalgamated before actually writing the page, as in the case of the MFT bitmap, but probably not in the more widely distributed MFT records.

 

So an MFT with say 25,000 spare slots could require as many as 250,000 writes to fresh pages. Probably not a lot in the overall scheme of things, but not something you'd want to inflict on your SSD too often.

[ccw62]

Thank you again! Need to check whether there are any tools around that are  -only-  wiping the MFT tables, i.e. not the entire drive.

 

Meanwhile:

when running Recuva and going thru the wizard, select drive, deep scan , etc. a drive may not show any entries at all

when from the result panel I select [scan]  again with the first 4 items tagged (Options->Actions) whilst leaving 'Scan for non-deleted files' untagged,

entries are displayed.

 

Curious to know why the results are different.

 

Any suggestions?

 

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