HDD partition cluster size analysis

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I’m seeking software that will analyze a selected (or all) partition and produce a report showing total “slack” (wasted) space and a recommended cluster size (resulting in minimal slack) for each selected partition.

I have never come across such a program, but surely it must exist somewhere out there!

I’d prefer Windows-platform software, but am interested in any software for any platform.

Any link to such a source of software would be greatly appreciated.

Thanks, Rob

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See this thread for a discussion on cluster size.

cheers, Paul

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Thanks Paul. That’s interesting but does not really address my question.

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I’m seeking software that will analyze a selected (or all) partition and produce a report showing total “slack” (wasted) space and a recommended cluster size (resulting in minimal slack) for each selected partition.

Rob,
Hello… I’m not positive that this is what you mean by “Slack” and wasted space… but “PD-11” Raxco shows blank spaces and fragmented parts of whatever disk you want … not sure what it is you mean by recommended cluster size? could you explain ? Regards Fred

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Rob,
Hello… I’m not positive that this is what you mean by “Slack” and wasted space… but “PD-11” Raxco shows blank spaces and fragmented parts of whatever disk you want … not sure what it is you mean by recommended cluster size? could you explain ? Regards Fred

Fred, as far as I know, the “fragmented space” shown by PD11 has nothing whatsoever to do with “slack” (wasted) space.

Here’s a very good description of “disk slack” (aka “cluster overhang”) …
Disk Slack Explained

While I have found programs that will report disk slack numbers, they do not perform an analysis and produce a recommendation for the optimal cluster size for the partition being analyzed.

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While I have found programs that will report disk slack numbers, they do not perform an analysis and produce a recommendation for the optimal cluster size for the partition being analyzed.

Rob,
Hello.. thanks for the link now i understand where your “coming from” So.. if I’m understanding correctly you would have to have a “variable cluster size ” for each program that is installed. That way you wouldn’t be using 4K clusters to contain a small amount of data…”wasted space”… Or somehow come up with some kind of compromise between the two. EX: adjust the “cluster size” so as not to waste space .Interesting idea …but haven’t the foggiest idea how you would do such . Thought that NTFS was a “fixed number” (4K).. One point …With PD-11 you can defrag and specify “consolidate free space” …but don’t know if that’s only dealing with 4K blocks, and not “squeezing ” some of the programs into little used clusters? Maybe some of the lounge “Big Dogs” will jump in here when they get back from holiday weekend. Regards Fred

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NTFS can use several cluster sizes: 512 bytes, 1 KB, 2 KB, 4 KB, 8 KB, 16 KB, 32 KB and 64 KB. The cluster size is fixed and is defined when you format the disk. There is some discussion on the “best” cluster size. Some people defend a 4 KB size as the best size for cluster size, as it is supposed to optimize disk access when the OS is writing to the paging files, as it writes 4 KB chunks during paging. A 4 KB cluster size means that the least space on disk occupied by any file is, at least, 4KB even if the actual space needed by the file is less than that. That’s what leads to “slack”.

My disks use a 512 byte cluster size. That’s probably because I was kinda appalled by the wasted space back when the file system was FAT and have used 512 bytes, since then, precisely to minimize slack space.

Fred, PD-11 will tell you what cluster size your partitions are using, if you choose Drive Properties -> Drive Info.

Regards

Rui

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I mean no disrespect, so please accept this in the positive way it is intended:

I have an older Dell desktop that came with an 80GB drive. A few months back
I added a 2nd internal drive ( 500Gb; and it cost me $48.)

Doesn’t the whole question of squeezing slack become moot as disk space becomes
cheaper and cheaper?

Dick

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Slack space is not really the issue, it’s what is the optimum cluster size for your usage.
I reckon more memory is the best cure for poor performance.

cheers, Paul

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Slack space is not really the issue, it’s what is the optimum cluster size for your usage.
I reckon more memory is the best cure for poor performance.

cheers, Paul

I don’t really feel I have performance issues. If anything, my laptop, with a 4K cluster, is way slower on disk access, than my desktop, with a 512 byte cluster. Sometimes, even though these discussions are interesting, I really think we sometimes worry about things that don’t have that big an impact on overall performance.
I completely understand that for many usages, a 4K cluster size is the recommended size. Never really bothered about my desktop using a smaller size.

@Rob,

This technet article is a bit old, but it has some references to tools and techniques that may be of interest.

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All these responses are interesting but are sorta missing the point of my original question.

Yes, I know the cluster size is fixed during the disk format process. And, yes, I know NTFS allows for a number of different cluster sizes to be selected.

I also know that we can select the “optimal” cluster size based on the type of files that will occupy the formatted partition.

A prime example is when the partition will be used to store video files exclusively. In my case, I chose a 64k cluster size for my “video files” partition. These files are usually at least several hundred MBs in size and can even be several GB in size. Also, the total number of files on such a partition is relatively low when compared to say the ‘C’ drive containing the OS.

So, to my original question, does a program exist that will not only report disk (partition) slack numbers for an existing partition, but also perform an analysis and produce a recommendation for the optimal cluster size for the partition being analyzed. Such a recommendation would only be useful to create and format a new partition using the recommended cluster size and then copying all the files from the “old” partition to the new partition.

The purpose of such a recommendation is to eliminate the guesswork involved in selecting the “best” cluster size to use during the format process.

Regards, Rob

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