SSD Defrag on Windows 8

**jwitalka** · 2012-07-03 14:06

I did a clean install of Windows 8 RP on an SSD. My understanding was that Windows 8 would recognize the SSD and disable defrag. I just went into the scheduler and discovered automatic defrag was still enabled. Had to manually delete the task.

Jerry

**jwitalka** · 2012-07-03 14:11

Did a search on SSD defrag in the Windows 8 IT forums and found this answer which explains why defrag is still enabled for SSDs in Windows 8:
Hello, In Windows 7 - we turned off defrag for SSDs as you mention in your entry; but in Windows 8, we have changed the defrag tool to do a general optimization tool that handles different kinds of storage, and in the case of SSD's it will send 'trim' hints for the entire volume;
SSDs are storage devices made of flash memory; flash memory unlike hard disks are block erasable devices - they can be written to at a byte level but need to erased at a block level; Trim is a storage level hint that was introduced in the Windows 7 days to indicate that Windows is not using certain regions of the storage device; NTFS will send these trim hints when files are deleted or moved from those regions; SSDs consume these hints to perform a cleanup in the background called as 'reclaim' that helps them get ready for next writes. The SSD may choose to perform the optimization immediately, store the information for later optimization or throw away the hint completely and not use it for optimization since it does not have time to perform this optimization immediately.
In Windows 8, when the Storage Optimizer (the new defrag tool) detects that the volume is mounted on an SSD - it sends a complete set of trim hints for the entire volume again - this is done at idle time and helps to allow for SSDs that were unable to cleanup earlier - a chance to react to these hints and cleanup and optimizer for the best performance. We do not do a traditional defrag (moving files to optimizer there location for space and performance) on SSDs.
Thank you for your question and I hope this clarifies the need to run the Storage Optimizer on a regular basis.

**Tinto Tech** · 2012-07-03 14:25

Interesting Jerry, thankyou.

Many people would have just thought it a bug in the new OS and disabled the defrag task since a "classic defrag" would cause wearout, but in point of fact disabling the Windows defragmenter in these cases could lead to more damage over time as trim messaging would be disabled.

Ideally Microsoft should allow a little bit of granularity here to allow people to see that defragmentation is not performed on an SSD, but trim messages are being sent by the new Storage Optimizer task that includes (and still appears to be labelled as) defrag.

**jwitalka** · 2012-07-03 15:42

Yes. I would have thought Microsoft would have used a new item in the Scheduler with SSD somewhere in the title (SSD Maintenance?) rather than use the existing Defrag item.

Jerry

**CLiNT** · 2012-07-03 15:50

Originally Posted by jwitalka

I did a clean install of Windows 8 RP on an SSD. My understanding was that Windows 8 would recognize the SSD and disable defrag. I just went into the scheduler and discovered automatic defrag was still enabled. Had to manually delete the task.

Jerry

So did I, but with Windows 7, which was a big surprise to me at the time. I doubt very much a defrag actually ran, but it was in the task scheduler ready to go all the same. I ended up disabling the service too at the time.

**bobprimak** · 2012-07-04 11:00

Do SSDs send their own "trim" messages, or does Windows have to do that for them? Does this differ from brand to brand?

**Tinto Tech** · 2012-07-04 11:53

The OS sends the TRIM commands to the SSD.

The TRIM command informs the SSD which pages of Flash storage are no longer used. The SSD firmware determines when to implement the command.

My understanding is that, in Windows 8, the mechanism used to send the TRIM commands is now different than Windows 7. Previously these commands would have been sent as required, but now Windows 8 will issue the TRIM during an "idle" time, allowing the SSD to respond more effectively. This process seems to marry up with the linked-to Wikipedia article above. In particular, the Shortcomings section of that article, describes TRIM commands as "Not Queued", and notes that a batch TRIM function would be more efficient. I think that's what Windows 8 implements in its Storage Optimizer function - albeit still under the moniker of Defrag.

**jesseinsf** · 2012-08-07 02:28

It is not labeled as Defrag. It is labeled as "Optimize and Defragment Drive" which means that it does both depending on what drive technology is used. An HDD performs both where as a SSD only performs optimization. Yes maybe it should be labeled as "Disk Optimizer" only. :-)

**Medico** · 2012-08-07 06:31

Tinto, thanks for posting some great info. This is the first I have heard of this as well, but then I do not have a SSD drive. It may be something for the future so it is good to know.

Since the Surface Pro tablet uses SSD technology, I would think this would be valuable info there as well. I might very well consider one of these tablets next year.

**jwitalka** · 2012-08-07 09:37

It is not labeled as Defrag

Its still labeled as Defrag in the task scheduler. If you do a Windows 8 search for Defrag, you get the title you mentioned. Its the entry in the task scheduler that may confuse some people who have been told to turn off defrag for SSDs. You definitely do not want to do that in Windows 8 as it performs the functions Tinto Tech mentions in his post.

Jerry

Jerry

**Medico** · 2012-08-07 11:36

Changing the name might have been easier for consumers to figure out what this is intended to do. Maybe Defrag or Optimizer.

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