Forgot to adjust cluster size before converting to NTFS, viable fix?

Bellator · Jan 10, 2008, 09:59 AM

Acer, in their infinite wisdom, installed XP pro on my laptop using FAT32 filesystem with 512 byte clusters.

I ran the command line convert utility to convert my drive to NTFS, unfortunately I forgot to use a utility like BootIt NG to re-align my files so that the convert utility could create 4K clusters, so instead I'm stuck with 512...

I know I can use a utility like Partition Magic to change the cluster sizes, but what happens to all the 512 fragments? If I defrag after changing the cluster size, will I end with 4K fragments like I want?

Also, does anyone know a quick 'n easy way to get an average file size on a disk? I'm wondering if I may need a larger cluster size, but outside of browsing through all my files and folders I'm not sure an easy way to determine optimal cluster size... thanks!!

RoyBatty · Jan 10, 2008, 10:47 AM

The average file size is shown in the Windows defrag analysis log. Start Defragmentation, select drive, analyse and "show report".

edit: The Partition Magic works perfectly for changing the cluster size. I used it many times without any data loss, but it's always recommended to back up important data to be sure.
And defragmentation can't change the cluster size - you can defrag the converted partition as usual.

Bellator · Jan 10, 2008, 01:18 PM

What happens to all the 512 segments? When you change the cluster size does that just mean that new files/folders will use that cluster size, or that the current 512 segments will be defragmented into 4k segments by partitionmagic?

thanks again

RoyBatty · Jan 10, 2008, 03:38 PM

The cluster size will be changed on the whole partition, including used space and free space. It's not possible to have two different cluster sizes on one partition.

mike2h · Jan 10, 2008, 04:18 PM

can one/both of you please explain the advantages of cluster sizes? i am getting ready to install another hd & make another partition for vista ultimate.

RoyBatty · Jan 10, 2008, 04:48 PM

Cluster is the smallest ammount of disk space a file will occupy, no matter how big the file is.
For example: When a 1 KB file is copied to a partition with 1 KB cluster size the file takes 1 KB of disk space. But if the file is copied to a partition with 8 KB cluster size it takes 8 KB, wasting 7 KB of disk space.

So, smaller cluster size is better for partitions with small files and larger cluster size is better for large files.

mike2h · Jan 10, 2008, 04:54 PM

thx. i knew that part. it is the tradeoffs i was more concerned with. sorry for not stating that.
basically i am going to have 2 raptor 75s in raid 0 for games only & a raptor 150 for the xp & vista partitions. i am also thinking about doing the 150 as games only & doing the 75 drives either individual or as a raid 1 setup with 2 partitions. lol.

RoyBatty · Jan 10, 2008, 05:04 PM

I think the smaller cluster size partition takes more time to defrag and it's harder on the reading/writing heads to "navigate" to the large ammount of clusters. But I'm not sure how much are todays modern drives affected by that...

mike2h · Jan 10, 2008, 08:41 PM

im just trying to figure out optimal cluster size for my setup. seeing as how they are supposed t obe 'enterprise class' drives I am not that concened about wear & tear. i think you are right about quality newer hd's not being as susceptible to durability problems as drives made more than 3-4 years ago.

Dyre Straits · Jan 11, 2008, 03:29 AM

Quote:

Originally Posted by mike2h

im just trying to figure out optimal cluster size for my setup. seeing as how they are supposed t obe 'enterprise class' drives I am not that concened about wear & tear. i think you are right about quality newer hd's not being as susceptible to durability problems as drives made more than 3-4 years ago.

I was just reading up on this not long ago and came across this very well written article. You might find it of interest, too:

Cluster Size

mike2h · Jan 11, 2008, 05:23 AM

thx! dont know why i didnt go there in the 1st place. its not like i dont have them in my favs folder

Matth · Jan 11, 2008, 06:08 PM

PCGuide - Ref - NTFS Architecture and Structures

For current NTFS implementations, the maximum default cluster size is 4k, for any patrtition larger than 2GB, the reason being support for NTFS file compression, limited to 4kB clusters.

Mind you, the same issue against running large FAT32 partions with 4kB clusters hasn't gone away in NTFS, it's still management of large numbers of clusters, versus increasing slack space, and still pans out much the same.

If you don't use NTFS compression, and files tend to be large, then larger clusters may be better, though NTFS is tuned for larger partitions.

In an operating sytem that normally uses 4kB pages, there is little reason to go smaller the 4kB clusters, as that would potentially split paging operations.

And to sum up, it will have to defragment, or more likely make extra fragments, in order to shift file data from adjacent smaller clusters of different files, so after re-clustering, a defragmentation would tidy things up.