Allocation unit size

[Conrad11]

Hi there,

I am formatting an external harddrive into an NTFS file system.

Its a 200GB harddrive, what size should the allocation unit size be (I am formatting in Windows Computer Management by the way).

Thanks.

 

[killersheep34]

I have always left it at default. Not sure if you change it, you'll get any better performance.

 

[rpstewart]

For NTFS there's no real reason to move away from the default, it's not like FAT32 where you needed bigger clusters for bigger disks.

 

[lopkinfop]

depends on what you will store on there. for a system disk, if you put it to the largest size, will take up more room as there are lots of small files. supposedly you should have the largest size for storing just videos but i have never noticed a difference so leave it to default

 

[fuzecx]

Hi All,

I know this is an old thread but I thought I'd post some findings with regards to formatting disks with different allocation size.

I've had a few older hard drives and flash drives lying around for a while and decided i'd play about with the ATTO Disk Benchmark tool and share the results.

The assumption is, default drive usage will be for secondary storage.
OS performance has not been tested.

I was very surprised to see that I could achieve small performance gains with all drives. Some where even shocking with much better write/read speed consistency.

All of the drives have now been formatted with the preferred allocation unit size.

I have applied colour scales to the tables to better show the results.

Preferred Allocation Unit Size: 512 bytes

Preferred Allocation Unit Size: 2048 Bytes

Preferred Allocation Unit Size: 16 kilobytes

Preferred Allocation Unit Size: 16 kilobytes


Well let me know what you think

Wayne

 

[klaxhu]

Wayne - it all depends on the type of data and the way the application is reading/writing the data on disk. You are right in saying that there could be massive differences, but those are just benchmarks.

In real life, it depends a lot on the application you use and on a PC, having so many type of apps that write in different blocks, and then on top you have huge files like movies and game files, it doesn't really matter.

Having said that, I would do default on a OS drive, and the biggest on a drive you would use for media.