Ideal cluster size for 1.5TB NTFS volume

Cluent said:

The average file size will be around 8 MB. I may also have a single very large file (500MB).

When you format the drive, the optimal cluster size should be selected automatically, probably 4KB.

If you are offerred a choice, remember that the largest size is not always the most space efficient, although with 1.5T that is probably not a big deal.

Cluent said:

I know 4KB is the default size for large drives, but is that necessarily best for performance with large files?

The trade-offs are between speed and space, to an extent.

With the speed of modern drives, a larger cluster size will give you only marginal improvement, if any - especially with NTFS.

From a space perspective, remember that each cluster is allocated as a lump (to use a really non-technical term :) ). What I mean is that a file of 20 bytes will take 4K - that is the minimum allocated size.

Again, with modern drives, you will not gain a lot in efficiency with a larger size - the sectors are arranged so that a single rotation will get multiple sectors, unlike drives in the old days where you had to manually set an interlace to optimize the speed.

Bottom line - I doubt if you would see any improvement in larger clusters.

TheSchaft said:

Bottom line - I doubt if you would see any improvement in larger clusters.

Would you get a smaller master file table with a larger cluster size?

Microsoft moved away from the File Allocation Table with NTFS, so I'm not sure the question applies.

Here are a couple of links that may help:

Optimizing NTFS

How NTFS Works: Local File Systems

I still really don't think you will see a marked improvement with a larger cluster size, or more disk space lost to indexing tables.

You're talking about 1.5T here - that's a lot of space. I have a 1T NAS and have loaded out the entire contents of two desktops and a laptop, plus Office 2000 and Office 2007 Enterprise CDs, and haven't even made a dent in the space.

At 1,500G, your 500MB files will be lost there. :)