SSD - To Defrag or not to Defrag

[ranmn7]

Ok, based on the mis-information that is rampantly thrown about here about the difference between defragging a ssd and not, lets look at the building blocks of ssd.

I have pulled up the specs on one of the chips used in ssd drives. This is not the only chip used, but the technology is very similar between these chips, and the functionality is typically the same, but speeds may vary.
NAND Flash Memory
MT29F2G08AABWP/MT29F2G16AABWP
MT29F4G08BABWP/MT29F4G16BABWP
MT29F8G08FABWP

• Endurance: 100,000 PROGRAM/ERASE cycles - this means the typical 2gb block can be written/erased 100,000 times.
• Page size:
x8: 2,112 bytes (2,048 + 64 bytes)
x16: 1,056 words (1,024 + 32 words)
• Block size: 64 pages (128K + 4K bytes)
• Device size: 2Gb: 2,048 blocks; 4Gb: 4,096 blocks;
8Gb: 8,192 blocks
• Read performance:
• Random read: 25μs
• Sequential read: 30ns (3V x8 only)
• Write performance:
• Page program: 300μs (TYP)
• Block erase: 2ms (TYP)

So, for those of you who 'ASSUME' that defragging will not improve performance, pay attention.

a sequential read at the chip level is nearly 1000 times faster than a random read. now most of the reads on these drives will be sequential, because the data is written that way, but the more fragmented the drive is the more often its going to do a random access vs a sequential access.

So, performance WILL be improved if the drive is extremely fragmented.

BUT, since you have a very finite limit on the number of write/erase cycles, I wouldn't defrag a ssd more than one time, or at the very most very very seldom. (like once a year maybe at most)

Based on this information, I have a ssd for my OS, and I have a IDE drive for my data. And I'll be disabling my windows swap file, or moving it to my IDE Drive.

 

[ranmn7]

Another note to extending the life of your ssd, which I'm still researching so I don't have all the answers yet, is that its not defragging thats going to kill the life span, but all your temp files.

Windows Temp directory, Cache files, browser history files etc.. I'll be looking into mapping these to my IDE drive so that my SSD doesn't get written/erased every time I clear my cache and history files. But that will have to be another thread I believe.

It appears that most of the people on this forum here have computer certifications, but very few appear to have electronic component backgrounds. And for this you need to have some exposure to the actual components.

Non-Volatile memory, ie.. flash memory has extremely finite write/erase cycles, normally 1000 cycles per block, and historically is used for ROM not RAM type applications. An SSD is a RAM application, and therefore everyone here is correct in that your SSD will have a very short life span if you're not paying real close attention to the number of write/erase cycles of the components.

According to the specs I posted in a previous post, even the chip I selected has a 1000 limit to the number of block write/erase cycles. Which is an extreme limit for a RAM type application. Please note, that chip manufactures guarantee that the chip can be written/erased 1000 times, and that it will take a minimum of this number of write/erase cycles. So the actual number before failure will be more than that minimum, but they do not state how many more, and do not guarantee more than the 1000.

As far as which chip is used on your SSD, and if there are a different number of write/erase cycles per block, I don't have that information. But, to date I have not seen a single non-volatile ram chip which has more than 1000 write/erase cycles per block. I will be looking for more information on this subject. And will post additional information as I find it.

That all being said, I am not nearly as interested in maximizing my performance, ie using diskpart etc.. as I am in extending the life of my SSD, so I really don't care if its 22uS slower reading because I didn't use diskpart.

 

[windude99]

Windows 7 says my ssd is 7% fragmented, but the ssd is still really fast. Do not EVER defrag and ssd. Be sure to turn off the schedule also. To do this, open Disk Defragmenter and click on "Configure Schedule" and then, uncheck the checkbox titled "Run on a Schedule".

 

[M1GU31]

defrag should only be used on hdd or ide drives, ssd drives don't need it because it doesn't make a difference and shortens the drives life

 

[allen1979]

mine won't even let me do it. doesn't give me the option. it shows it on the screen, but will only let me defrag the hhd

 

[cyclic]

That all being said, I am not nearly as interested in maximizing my performance, ie using diskpart etc.. as I am in extending the life of my SSD

So listen to the posters who have said, as I am don't defrag it will reduce the life of your SSD, not extend it.

 

[rknapik]

do not defrag an ssd

 

[highstream]

Ok, based on the mis-information that is rampantly thrown about here about the difference between defragging a ssd and not, lets look at the building blocks of ssd.

I have pulled up the specs on one of the chips used in ssd drives...

So, for those of you who 'ASSUME' that defragging will not improve performance, pay attention.

a sequential read at the chip level is nearly 1000 times faster than a random read. now most of the reads on these drives will be sequential, because the data is written that way, but the more fragmented the drive is the more often its going to do a random access vs a sequential access.

So, performance WILL be improved if the drive is extremely fragmented.

BUT, since you have a very finite limit on the number of write/erase cycles, I wouldn't defrag a ssd more than one time, or at the very most very very seldom. (like once a year maybe at most)

The paragraph that performance will be improved when extremely fragmented appears on the face of it to contradict the paragraphs immediately before - much slower random vs. sequential access - and after, i.e., why defragment a drive that's extremely fragmented if that's the best performance? What am I missing?

I should add that after 2-3 months a then recently-purchased Corsair Force 3 60gb SSD seemed to slow considerably and defrag changed that immediately.

 

[Hopalong X]

Instead of defragging an SSD it should be allowed to sit idle usually for one hour minimum so the GC (garbage collection) and TRIM will do the cleanup.
Check the manufacturer. Also if you check the manufacturer web site it specifically will say do not defrag.
It also will void the warranty.

Defrag causes excess wear. After defragging the SSD the SSD firmware will put the files right back where it wants them. So the files get moved twice.

No argument intended just pointing out the reason for not doing defrag.

Good luck.

 

[linnemeyerhere]

I don't know if I believe the defrag and it wears the drive out pre-maturely stuff, but SSD's don't benefit to any degree to a data re-alignment so why ever take the risk?

 

[highstream]

Instead of defragging an SSD it should be allowed to sit idle usually for one hour minimum so the GC (garbage collection) and TRIM will do the cleanup.
Check the manufacturer. Also if you check the manufacturer web site it specifically will say do not defrag.
It also will void the warranty.

Defrag causes excess wear. After defragging the SSD the SSD firmware will put the files right back where it wants them. So the files get moved twice.

No argument intended just pointing out the reason for not doing defrag. Good luck.

Your post got me to check the Plextor warranty and other information (128gb M3 Pro). The warranty is 5 years and there is nothing there or anywhere else about not defragging. So, would you mind documenting your claim for us?

 

[Hopalong X]

Intel® High Performance Solid State Drive — SSD Frequently Asked Questions

Do I need to defragment my Intel® Mainstream Solid-State Drive (using Windows* Disk Defragmenter* or similar program)?
No. SSD devices, unlike traditional HDDs, see no performance benefit from traditional HDD defragmentation tools. Disable any automatic or scheduled defragmentation utilities for your Intel SSD. Using these tools simply adds unnecessary wear to the SSD.

Also in the owners manual. Warranty I have not found a specific as of yet.

If no mention is made of warranty issue at Plextor okay.

 

[highstream]

There has been increasing note in reviews and discussions like these that the quality of SSDs has improved over time and the initial stricture about wearing them out, such as by defragging, seems to have become less of an issue, if one at all. It's not my field, but that's what I keep seeing.

 

[Hopalong X]

O&O is one of the top makers of after market defrag software.

Here is their input on the subject.> http://www.oo-software.com/en/docs/whitepaper/ood_ssd.pdf

 

[highstream]

Thanks for that link. It's getting harder to justify buying an optimizer - not that I have - when all the software can do with SSDs is use what's already there in Win 7 - TRIM.

 

[Hopalong X]

I did not suggest buying anything.
O&O sells a defrag software and they are telling the would be users to not do so on SSD's.

After reading up on your Plextor besides TRIM it does have a "cleanup" of some sort in the firmware which some manufacturers call GC/garbage collection.
The system needs to sit idle for an hour plus for TRIM and "GC" to work.
Once a week or month or when it seems to be getting sluggish should be sufficient.
Should be no guarantee.

Good luck and enjoy your SSD.
Mike

 

[Alejandro85]

My vote is that YES, there is a good reason to defrag a SSD drive. While many of the benefits it carries aren't applicable to the nature of SSDs, as you get no gain in speed, there is one benefit: file system recuperation.

Suppose you accidentally delete a file, and want to un-delete it. All programs work by reading the remaining directory entries, then guessing where it was stored on disk all remaining parts. A well known assumption is that the file will be contiguous on disk, and if it's actually not, parts of a recovered file might be corrupted or the file not recoverable or usable at all. By defraging your disk, you assure that the main recovery method remains valid.
Also, if a catastrophic system failure blows up some system areas of the filesystem, recovery software will have an easier time and greater success chance of a proper recover with a fully defragmented system.

 

[Hopalong X]

Just shoot me. :banghead:

 

[essenbe]

I own 5 SSDs from 3 different manufacturers. None recommend defragging SSDs. There is a reason Windows turns off defrag for SSDs. SSDs write data different than a spinning hard drive. Most, if not all, defragmenting programs are programmed for spinning hard drives and will look at an SSD and think it needs defraging when in fact it does not. Defreag will help a spinning hard drive by putting the data in fewer locations so it can be found easier. SSDs have no moving parts and therefore do not need defragging. Intel's tool box will turn off defrag, Windows will turn it off. There is a reason that happens.