Does HDD filling up really impact performance?

[rawdawg]

I've seen it here before where people say performance goes down significantly as your HDD fills up. Some explanations have been about the platters having lower read speeds as data writes towards the inside, but I've seen such claims rebutted.

My new MBP is maxed out with RAM and I have multiple external drives. My internal is 500Gb and I've always worried about keeping it under 75% full, but if it's not necessary I would like to add my photos and music to it.

Can someone please shed light on whether or not it effects HDD performance? (I'm not talking about when you have under 5Gb or even less available)

Also, since I do heavy graphic and video work, is it important to have a scratch disk not on my media drive? My media drive is currently a RAID 0 I have hooked up via eSATA. I thought dedicated scratch drives are a thing of the past. Should I use my external FW800 (non-RAID)?

 

[Beefy]

Can someone please shed light on whether or not it effects HDD performance? (I'm not talking about when you have under 5Gb or even less available)

In my experience, yes.

 

[mrsir2009]

No, I don't think so. BUT:

When you save soemthing to the hard drive it takes up a block of data. Then when you edit it and save it again the new bit gets saved somewhere else. So when you open a file thats been edited multibable times, it will have to find ALL the data from DIFFERENT parts of the HDD.

So its not actually filling it up that slows it down. Saving files and editing them lots causes THAT SINGLE FILE to slow down. NOT THE ENTIRE HDD.

--

Not completely sure I'm right, but thats what I've heard!

 

[ljonesj]

yes i know with windows the page file expands and contracts to a certain amount if it needs unless u set it to use a certain amount to move stuff out of ram and vice versa i know in linux u have a swap partition i dont know how osx does with a page file or swap area but it could hurt it not have enought space on the hard drive


ps just got in from work excuss the messy typing i am dead tired and cant type at the moemnt

 

[aeboi]

yes, it does.

 

[tombilske]

mac uses HFS+ as it file system, and this eliminates the need for defragmenting the hard drive because it moves all of the blocks of data for one file so that they are together automatically. It cannot do this efficiently if there is less than 10-15% free space in the drive, and this results in fragmented files which means lower read/write speeds. so yes, it will impact on the performance of the drive if it is nearly full

 

[northerngit]

mac uses HFS+ as it file system, and this eliminates the need for defragmenting the hard drive because it moves all of the blocks of data for one file so that they are together automatically. It cannot do this efficiently if there is less than 10-15% free space in the drive, and this results in fragmented files which means lower read/write speeds. so yes, it will impact on the performance of the drive if it is nearly full

While this is somewhat true, there are other factors. HFS+ will only defragment files that are 20MB or less. If you have large video files, or VMware images, you'll find these fragment as badly as Windows NTFS.

From a CNET article:

Fortunately, Mac OS X's HFS+ filesystem has some safeguards against avoidable fragmentation. First, the filesystem avoids using space recently freed by recently deleted files whenever possible, looking instead to potentially larger, already free portions of the disk first. Second, Mac OS X 10.2 has a routine that clumps smaller portions of disk space into larger portions on the fly. Finally, Mac OS X 10.3.x can automatically defragment some files through a process called "Hot-File-Adaptive-Clustering." Though these routines have undoubtedly have made consequential fragmentation a less common occurence, their efficacy is not beyond question. First of all, though they can reduce fragmentation of extant files, they can also cause remaining free portions on the disk to become smaller in size, potentially leading to more fragmentation down the road as new files are written. Second, the automatic defragmentation routines will not work on certain files -- specifically those above 20 MB nor those fragmented into 8 or fewer segments.

A full drive will have a harder time finding contiguous blocks, leading, as the PP says, to fragmentation.

Moreover, the inner platters of a drive are much slower than the outer ring. While block writes are random, the more near capacity the drive, the more often you'll hit this slower boundry.

Of course, this point is mute on SSD drives.

I've purchashed iDefrag and Drive Genius 3, both of which gave huge imporvments to performance on my MacBookPro - especially VMware.

 

[rawdawg]

Thanks for all the replies. Sounds like keeping the drive over 90% capacity wouldn't be a bad idea with all this in mind.

Is there a way I could force my music to be on the inner portion of the platter? (Other than erasing and partitioning since I don't want to do that)
If my drive is over half full now, if I were to toss in a bunch of video files so that when I add my music my drive would be full and then I go back and delete the video files to free up that space, would that force my music in the inner portion of the platter?