Should SSD's be defragmented

NavyLCDR said:

Unlike defragging, Trim on an SSD is just Trim, it doesn't matter which program initiates it the results will be exactly the same. Trim doesn't move files, trim resets storage locations on the SSD that have had data previously stored there. There are two steps required to make a storage location available on an SSD. The first step is to delete the previous data. The second step is to reset the storage location for reuse. The first step is done on-command at the moment it is required. The second step is only performed when either there are no more reset data locations available for use or periodically, hopefully during idle periods. By waiting for an idle period to do the second step, the SSD performance is increased. The second step is the trim operation.

Hi there
I still don't see the need for TRIM on modern SSD's -- why does one need to reset storage location when given that an SSD is basically like a LOT of RAM -- any location is equal to any other location so why should moving data make any difference at all epcially since most of the index can be held in RAM - and even a simple binary search can give very fast access to a HUGE number of "addresses" in a very few number of operations.

It's like the 6 in 49 lottery numbers -- 123456 is just as likely to come up as any of the other 14 million or so combinations.

The electronics in the I/O controller will take care of any specific firmware improvements.

A lot of these old utilities and ideas came from the early days of HDD's and ist gen of SSD's -- these days you are much more advised to leave this stuff well alone !!.

Of course like everything else YMMV but when using things like DEFRAG you need to know why those utilities existed in the first place and make sure that you really need them.

Cheers
jimbo

So Jimbo, I gather you wouldn't prefer to have Diskeeper set loose on any type of SSD. Here's a different question. Is there a chance an SSD might catch on fire if letting a program like Diskeeper optimize it every day?

jimbo45 said:

Hi there
I still don't see the need for TRIM on modern SSD's -- why does one need to reset storage location when given that an SSD is basically like a LOT of RAM -- any location is equal to any other location so why should moving data make any difference at all epcially since most of the index can be held in RAM - and even a simple binary search can give very fast access to a HUGE number of "addresses" in a very few number of operations.

An SSD is made up of a whole bunch of cells to hold data. Let's say that cell A1 has a 2 in it as part of a file. The file changes and that 2 becomes a 5. What the SSD does is look for the next open spot to shove that 5 into. So lets say that next open spot is cell A10. So what you have now is cell A10 with the 5 in it that is part of the actual file, and you still have the 2 in cell A1 that isn't attached to any file.

Over time the SSD is going to run out of empty cells to shove data into and there are going to be a whole bunch of cells with obsolete data in them not attached to any file. Then what happens? In order to write new data the SSD has to go to one of the cells with obsolete data, clear that out, then write the new data. That's going to make it close to twice the time required to write new data and slow down the SSDs performance greatly.

What the trim command does is it goes through and gets rid of all the obsolete data in one operation, resetting all those previously used cells so they can be written to again.

And that's why you run Trim on a routine basis - you slow down the SSD performance for say 5 seconds out of every month to clear out the garbage. If you don't, then the garbage just builds up until the SSD is full, at which time for each piece of data that needs to be written, one piece of garbage must be cleared out and now your SSD performance is slowed down on a permanent basis - until the Trim command gets issued.

Trim has nothing to do with moving data. Trim clears out all the garbage in one sweep to provide clean cells available to hold data again.

That's a very clear explanation of what is taking place on the SSD's. Consequently, I have TRIM all trimmed up and ready to go. Thanks for this.

jimbo45 said:

Why would an SSD need to be defragmented. Te only reson to defrag an HDD is that parts of the file exist over physcally different sectors and the HDD has to rotate to position the read mechanism to pick the file up -- obviously the more chunks scattered over the HDD the more the seek and Read accesses are required to get the file.

That's the usual reason to defragment a drive, but defragging typically does more than just rearranging sectors to make them contiguous, it also optimizes the file structures on disk (such as the MFT) to reduce wasted space and reduce the number of entries that have to be navigated to read an entire disks directory structure.

The Windows disk optimizer does, on occasion, defrag these structures in addition to performing a TRIM on SSD drives. However, this is not a full blown defragment.

Another reason to perform a defrag is to consolidate free space, so that you can shrink a partition. Suppose you have a partition that uses only a single block at the end of the disk space, then resizing won't be allowed even though you may have plenty of disk space. Having said that, it's a pretty rare circumstance for most people.

Mystere said:

Another reason to perform a defrag is to consolidate free space, so that you can shrink a partition. Suppose you have a partition that uses only a single block at the end of the disk space, then resizing won't be allowed even though you may have plenty of disk space. Having said that, it's a pretty rare circumstance for most people.

If you use a program such as MiniTool Partition Wizard, the program will move the files out of the way needed to shrink the partition. That's why you can remove space from the front of a partition with MiniTool Partition Wizard, but you can't with Windows Disk Managment. Windows Disk Management did not have the capability to move files written into it. I suppose you could call the partitioning program moving files as "defragging" to some degree.

Layback Bear said:

1. As far as I know their is no manufacture of SSD's that recommend using a defrag program on their SSD's. What I have read from manufactures is they do not want their SSD's defraged with any program.

I wouldn't say they "don't want their SSD's defraged with any program". That sounds like they are actively telling users what they can and can't do with their drives. It would be better to say they do not recommend defragging, as it normally serves no useful purpose and can (slightly) decrease the lifetime expectancy of the drive (although if you were to defrag it often each time would decrease that life expectancy).

Again, there are plenty of defrag tools that are smart and understand that SSD's don't need general defragging (though they sometimes need filesystem optimization).

So it's good to optimize drives, even SSD's, but you should only use an SSD aware optimizer.