Shortenning SSD Life by Defragging?

[sapearl]

I recently began using a defragging program called Defraggler, and when I started to defrag my boot drive which is an SSD it stated the warning that it may shorten its life. I received no such warning when I defragged my conventional spin drive.

Is there something about SSD's that makes them susceptible to damage or wear through the defragmentation process?

[rpaul]

Please, please don't defrag your SSD. They are not like spinny hard drives, where the physical position of the data matters. Defragging SSDs just creates unnecessary writes that reduces the lifespan of the drive.

[tim]

Don't defrag your SSD, it's unnecesary. SSDs wear out with writes so a defrag shortens its life.

[sapearl]

Originally Posted by rpaul

Please, please don't defrag your SSD. They are not like spinny hard drives, where the physical position of the data matters. Defragging SSDs just creates unnecessary writes that reduces the lifespan of the drive.

I knew there was the physcial difference, but I was unclear on the concept of unnecessary writes. I take it the "write medium" is significantly from the magnetic media of conventional drives? Thanks for the advice Rob - you too Tim

[rpaul]

Basically, SSD's are made up of lots of flash memory cells, which wear out after many thousands of writes. (This happens to all flash memory.) While the drives will still last for years under normal usage, defragging adds lots of unnecessary writes as it shuffles the data around the drive without creating any benefit, since SSD's don't have to physically "seek" the same way spinny HDD's do.

[hollis_f]

There are two good reasons why you shouldn't defrag your SSD.

1. It will reduce the lifespan of the drive. As Rob said, the memory cells can only be written to a limited number of times.

2. It's pointless. Your SSD deliberately fragments the data that it writes to the drive. You don't want the same sets of memory cells being used all the time (because they'll wear out quickly). So the drive controller spreads the data over all of the cells - it's called wear levelling.

[sapearl]

Originally Posted by hollis_f

There are two good reasons why you shouldn't defrag your SSD.

1. It will reduce the lifespan of the drive. As Rob said, the memory cells can only be written to a limited number of times.

2. It's pointless. Your SSD deliberately fragments the data that it writes to the drive. You don't want the same sets of memory cells being used all the time (because they'll wear out quickly). So the drive controller spreads the data over all of the cells - it's called wear levelling.

Thanks for that explanation Frank - gives me better insight into the tech. I had a general awareness but that fleshes it out.

I wonder how similar/different those memory cells are to the structure of our CF and SD cards? We constantly write to, erase and format those little things, and the better ones are supposed to last for years.

[CameraMan]

Interesting. I never knew this but it makes total sense.

[sapearl]

Originally Posted by CameraMan

Interesting. I never knew this but it makes total sense.

I wonder if the SSD's controller and operating system (?) mark of bad sectors or their equivalent (as on a conventional drive) when these cells go bad or become unreliable. I'm sure it must communicate in some fashion: "Don't write data right here......"

[hollis_f]

Originally Posted by sapearl

I wonder how similar/different those memory cells are to the structure of our CF and SD cards? We constantly write to, erase and format those little things, and the better ones are supposed to last for years.

They are very similar. CF cards have the same problem with limited read/erase cycles, and they use the same wear levelling technique to even out the wear. You'll sometimes read posts from people giving advice on how one should try to minimise that wear, but they're normally a load of old tosh. Here's why...

Most of the memory used for CF cards can handle something like 10,000 write/erase cycles. So a 16GB card can handle about 160TB before it starts to wear out. That's 160,000,000 megabytes. If each of your raw images is 25MB then you can write 64 million images to your card. If you shoot 1000 images per day, every day, then your card will wear out after about 175 years!

[hollis_f]

Originally Posted by sapearl

I wonder if the SSD's controller and operating system (?) mark of bad sectors or their equivalent (as on a conventional drive) when these cells go bad or become unreliable. I'm sure it must communicate in some fashion: "Don't write data right here......"

Yes, it does.

[Pit]

Not only that, it also has spare or over provisioned memory sectors that are there to replace the failed blocks.

Originally Posted by hollis_f

Yes, it does.

[sapearl]

Originally Posted by Pit

Not only that, it also has spare or over provisioned memory sectors that are there to replace the failed blocks.

Well now THAT'S interesting.

Do we know if this "spare" amount is included the spec of the drive? What I mean is, if I purchase a drive that claims to be 256GB is there really xx% more drive space above and beyond that to allow for future failed cels?

[hollis_f]

My 300GB Intel SSD is 300,066,406,400 bytes according to Windows.

[sapearl]

Originally Posted by hollis_f

My 300GB Intel SSD is 300,066,406,400 bytes according to Windows.

So basically then Frank, it is what it is just as is the case with conventional disks .

We buy disks at XXXGB, and realistically over the life of the disk a certain percentage of sectors will go bad on average. On long-lived disks/storage devices that survive healthy for years, I don't imagine this is a large number because if it is then they simply crash or fail. So I guess the moral of the story is always to buy more than what you think you need.