What exactly is disk defragmentation and is it really that important?

[KyleMadrid]

Hi all,

I bought a new computer about 8 months ago, and I've always been very careful with it and am always looking to do what's best for it (in terms of maintaining and looking after it). I have never run a disk defragmentation before but I've read that it's important and can help make the computer run faster. My computer is not running slow or anything like that, but I've read that some people do it once a week...

So my questions is: What exactly does the disk defragmenter do, and should I do it even though my computer doesn't seem to have any problems?

I read this in an article on 'about.com', but I still don't quite understand what it means...

"Think of your hard drive like a file cabinet. If you're like most people, you've got your papers stored in alphabetized folders so you can find things easily. Imagine, though, if someone took the labels off the folders, switched the locations of all the folders, and moved documents into and out of folders at random. It would take you a lot longer to find anything, since you wouldn't know where your documents were. That's sort of what happens when your hard drive gets fragmented: it takes the computer much more time to find files that are scattered here, there and everywhere."

Does this mean that it re-organizes your files? Because if so, then that would very annoying, because I already have my files organized exactly the way I want them... or am I missing something?

Also, I have many important files on my hard drive, and don't currently have any of them backed up, because I don't have anything to back them up with at the moment... so I just want to know if there is any possibility for something to go wrong during the defragmentation and al my files be deleted?? (I know, I'm very paranoid, but like I said, I have none of my files backed up)

Thanks in advance

[Wolfen]

Through your every day use of your computer, web surfing, installing/deleting programs and what not your HDD get pockets of empty space and programs and files get fragmented. Your computer will slow down when starting up and starting programs. It is a good practice to defragment the hdd at least every week or two to keep things together.

I suggest you invest in an external hdd with built in back up software if you don't want to lose anything important.

[KyleMadrid]

Through your every day use of your computer, web surfing, installing/deleting programs and what not your HDD get pockets of empty space and programs and files get fragmented. Your computer will slow down when starting up and starting programs. It is a good practice to defragment the hdd at least every week or two to keep things together.

So does this mean that it doesn't actually reorganize my files?

I suggest you invest in an external hdd with built in back up software if you don't want to lose anything important.

Yes, I plan on doing that. Do you think I should wait until I've backed up my files before defragmenting my hard drive?

[Cornucopia]

All modern defragmenters use a procedure that is a combination of:
1. Check to see if not contiguous, if so
2. Copy to temp area, or to empty end area
3. Verify that recombined sections are still valid, with no errors
4. Delete original
So as you can see, The process doesn't delete an original till it can already commit to a safe copy

Scott

[KyleMadrid]

OK, thanks for that Scott.

[D_Knife]

So does this mean that it doesn't actually reorganize my files?

To answer this question is more complex.
How you have your files "organized" in disks and folders and whatnot could be called "logical" ordering (there's a LOT more to it than this but this is enough knowledge) - this order is not changed by a de-fragment. If you have files placed into certain folders this will not change.

The underlying data the actual files as seen by the operating system are what gets optimised in a de-fragment.
It makes no visible change to you however files that were separated or split are know whole again

[KyleMadrid]

It makes no visible change to you however files that were separated or split are know whole again

Sorry if this is a stupid question... but does this mean that if I have split a video file (say, with mkvmerge) that it will make the file go back to it's original state?

[Hoser Rob]

It makes no visible change to you however files that were separated or split are know whole again

Sorry if this is a stupid question... but does this mean that if I have split a video file (say, with mkvmerge) that it will make the file go back to it's original state?

Nope. No worries there. The defrag process just moves things around. It doesn't know or care what you did to create the file.

But re "Do you think I should wait until I've backed up my files before defragmenting my hard drive?"

YES. If you lost power or had some kind of malfunction during defragging it would not be good.

Actually, it's funny how many stores push extended warranties on you when the thing they should be selling you ... if they actually cared about you rather than the markup, probably 80% for extended warranty ... is an external backup drive.

Backup drives should really be part of the initial purchase of a computer. The data is what's valuable. Not the hardware. Especially for business. In business use the hardware is a small fraction of the worth of the data.

Speed is good.

[KyleMadrid]

It makes no visible change to you however files that were separated or split are know whole again

Sorry if this is a stupid question... but does this mean that if I have split a video file (say, with mkvmerge) that it will make the file go back to it's original state?

Nope. No worries there. The defrag process just moves things around. It doesn't know or care what you did to create the file.

But re "Do you think I should wait until I've backed up my files before defragmenting my hard drive?"

YES. If you lost power or had some kind of malfunction during defragging it would not be good.

Actually, it's funny how many stores push extended warranties on you when the thing they should be selling you ... if they actually cared about you rather than the markup, probably 80% for extended warranty ... is an external backup drive.

Backup drives should really be part of the initial purchase of a computer. The data is what's valuable. Not the hardware. Especially for business. In business use the hardware is a small fraction of the worth of the data.

Speed is good.

ok, thanks

[jagabo]

Think of your hard drive as something like a book. Each file is a chapter. In a normal book the pages of a chapter are all sequential. The table contents tells you that chapter 3 starts on page 55. You know that the following text will be on pages 56, 57, 58, etc. But with a computer the pages don't have to be sequential. At the bottom of each pages is a message that tells you where the next page of text is. After reading page 55 the next page might be 90. Then the next page 27. The next page 114. All that mapping of pages is invisible to you, but flipping through pages to find your data is time consuming for the computer. Defragmenting the drive rearranges the pages so they are in sequential order, to speed access. That doesn't effect the table of contents -- what you see as the organization of the files. Just where the data is located on the disk.

[KyleMadrid]

Think of your hard drive as something like a book. Each file is a chapter. In a normal book the pages of a chapter are all sequential. The table contents tells you that chapter 3 starts on page 55. You know that the following text will be on pages 56, 57, 58, etc. But with a computer the pages don't have to be sequential. At the bottom of each pages is a message that tells you where the next page of text is. After reading page 55 the next page might be 90. Then the next page 27. The next page 114. All that mapping of pages is invisible to you, but flipping through pages to find your data is time consuming for the computer. Defragmenting the drive rearranges the pages so they are in sequential order, to speed access. That doesn't effect the table of contents -- what you see as the organization of the files. Just where the data is located on the disk.

Great explanation, jagabo. Thanks very much

[Nelson37]

In addition to speed, think of the reading process like a record player. When a chunk of data is scattered all over the disk, there is a lot of extra movement to read it all. Having the data in one single arc means less wear and tear on the head mechanism, as well as faster.

Defragging itself is extra wear and tear, and for most users can be once a month or once a quarter, even once a year. Daily is rarely a good idea.

The more full the drive, the more fragmented it is likely to be, also slower to defragment.

My rule of thumb is "If it takes a long time, do it more often, and if it is extremely quick, you can wait longer next time."

[KyleMadrid]

In addition to speed, think of the reading process like a record player. When a chunk of data is scattered all over the disk, there is a lot of extra movement to read it all. Having the data in one single arc means less wear and tear on the head mechanism, as well as faster.

Defragging itself is extra wear and tear, and for most users can be once a month or once a quarter, even once a year. Daily is rarely a good idea.

The more full the drive, the more fragmented it is likely to be, also slower to defragment.

My rule of thumb is "If it takes a long time, do it more often, and if it is extremely quick, you can wait longer next time."

ok, I see. Thanks

[jman98]

Good thread that I'd like to add to.

Do NOT defrag SSDs!

Solid State Drives use a special algorithm called TRIM to do something like defragmentation and all modern OSes (Linux, recent versions of OSX, Windows 7 and above and maybe even Vista) support TRIM. If you defrag an SSD you are adding wear and tear to it and helping to shorten its lifespan. Any SSD drives should have defrag turned off on them under Windows.

It's a big simplification, but Linux and OSX don't need defragmentation run because someone actually put some thought into the file systems they use. This is a Windows specific task and it is needed because of Windows' "just make it work!" philosophy that shunned good programming practices in favor of getting things working quickly. SSDs do need TRIM run regardless of operating system as it's a way to make your SSD last longer.

[KyleMadrid]

ok, interesting... so how do I find out if I have a Solid State Drive?

[jagabo]

so how do I find out if I have a Solid State Drive?

Go do Device Manager and look at the "Disk drives" section.

[KyleMadrid]

did what you said, and it says I have a Hitachi SATA disk device...

[jagabo]

Does it give a model number? If so, look it up. I don't think Hitachi makes consumer grade SSDs. Many SSD drives have SSD in the device name in Device Manager.

[KyleMadrid]

Yes there is a model number. Too bad I can't copy and paste it, haha, it's very long, but yes, I'll look it up.

[KyleMadrid]

Just looked it up and couldn't find anything that said it was an SSD. So I guess it's safe to defragment it then. Just have to wait til I get an external hard drive.

[KyleMadrid]

Also, just another question...

I know that all electronic devices can potentially die without warning, but how common is it for an HDD to die within it's first year? I desperately want to get an external hard drive but will probably have to wait another couple of months before I do, and I just don't even want to think about how I would react if I lost all my files suddenly...

I know it's unlikely for it to die within 1 year, but would just like to know from people with a better understanding/experience.

[jman98]

It's not common for a hard drive to die within a year but it's not impossible. The odds are against it. I've seen a lot of hard drives develop boot problems of various kinds under Windows and I've never personally seen a drive that couldn't have data recovered off it, but if you cannot live without your files, getting a backup drive sooner rather than later is your best insurance against disaster. Is this a desktop or laptop? If it's a desktop, I strongly recommend connecting it to a UPS to assist in longevity. I live in a place without reliable power and years of not using UPS devices has just resulted in the inevitable "my drive won't boot anymore and I can't fix it" problem at some point on every computer I've ever owned. I stopped this problem when I started using UPS devices.

[KyleMadrid]

Yes it is a desktop, but I don't have a UPS, all I have is a surge protector. Just googled what a UPS was, because to be honest I had no idea what it was, and it does sound like a good thing to have. When I have a bit more money to spend on an external HDD, I'll definitely look into getting a UPS too. Unfortunately in the 8 months that I've had this computer, it has already been unexpectedly shut down by 3 power outages... (There was a constant problem with power outages in my suburb for about 2 months earlier this year, and only just recently was it properly fixed)

[OllieTSB]

Kyle, I think A Magazine's Long Article is a better analogy. You've read large magazines, probably found an article that is 'continued' from one page to the next. As it goes along, it's fragmented into smaller and smaller parts. One reason for this is to drag every reader thru more advertising pages.

But this slows up the reading process. "Wouldn't it be so much quicker if I could just read all 5 pages in 5 pages instead of scattering them all over?" Yes. But of course, the magazine WANTS to drag you thru more advertising, more pages.

Your computer is the same way - the ability to assemble a file and display it continuously on your scrolling screen is hampered by "wading thru page after page" - just like magazine readers are forced to do.

Defragmentation gives us a chance to let the computer assemble a file's pieces and relocate them into a continguous zone. Faster assembly, faster display times. You and I may not notice it, but the computer does.

[TreeTops]

Why does everyone worry so much about de-fragging? Win 7 does it automatically. No need to worry or fret about it.

[Nelson37]

The probability of a hard drive dying is directly related to the amount of damage it would do if it did.

Bought a WD caviar black 1TB drive about two years ago. My movie and utility collection was scattered all over a 400, 500, and 320 GB HDs.

Didn't get around to all the re-arranging and copying for a while. Got that done, then got around to formattiing the original drives. Finally had ALL my video on one drive, not scattered around my network. Then I noticed one of my videos had a glitch. Just a bad file, I thought. Then another file, and another. Better get those formatted drives back in the system and back up. Yep, gonna do that first thing tomorrow morning.

No drive. No data. BAM. Got about half of it back, Less after removing corrupted files. 5 year warranty on the caviar blacks, I think that was only the second warranty return I've ever had on one of those.

Also, technically it's a battery back-up, not a UPS, but GET ONE, Get One NOW, they are extremely important. IMO the APC brand is the best, or Panamax or Minuteman.

[Constant Gardener]

Why does everyone worry so much about de-fragging? Win 7 does it automatically. No need to worry or fret about it.

Indeed. Windows 7 automatic defrag, every week, is quite adequate. When I use a utility such as Defraggler to look at my hard drives, the only files that are significantly fragmented are those written since last week's scheduled defrag.

@Nelson 37. Data knows when it is unique. Then it corrupts. By the same reasoning, if you have adequate backups, then you will never need them. (Not quite true, but close enough for government work.)

[Nelson37]

Exactly right, and if you religiously make backups on a regular basis, and after 5 years of doing this you one day really, REALLY need them, that's the day that the backup system failed to work.

[jman98]

Why does everyone worry so much about de-fragging? Win 7 does it automatically. No need to worry or fret about it.

Usually it's because some friend told some inexperienced person about it and painted a dire picture that if the inexperienced person didn't defrag their drive immediately that some catastrophic loss of data was just around the corner.

If all of Windows wasn't such a half-assed POS nobody would need to do this at all. Sane file system technology has been around longer than Windows. Here it is almost 30 years later and we users are still paying the price for Bill Gates' inability or unwillingness to license better technology and his programmers' attempts to reinvent the wheel have led to this ridiculous situation. To be fair to Microsoft to a certain extent some decisions were sort of forced on them by the awful architecture of the early PC CPUs, but there are still a lot of things that Microsoft did in a really stupid and thoughtless way simply because they could since they had no real competition. There was no pressure to do thing right - if it worked, then it was good enough.

[fritzi93]

I have Windows defragmenter turned off. I use Defraggler instead, as the Windows 7 defragger is remarkably uninformative.

Here's the thing that I don't quite understand:

Every now and then I check my hard drives with Defraggler. I have it set to exclude my SSD of course. None my (fairly recent) SATA hard drives ever show much fragmentation, even though they see a lot of use. OTOH, I have an old PATA 320 GB drive (7-8 years old?) that is only used for storing OS backup images and some rarely used files. I do the backup to a SATA drive and then copy it over to the PATA drive (just for insurance). The drive gets almost no usage otherwise, yet when I check it after copying a backup image over, it's always very fragmented. And it takes quite a while for Defraggler to defrag it.

What's the deal with that? Is the firmware in newer drives more...efficient? Is Defraggler a poor choice?