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Best Filesystem/Allocation unit size to use?

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Last seen: 5 years 6 months ago
Joined: 2007-05-07 03:47
Best Filesystem/Allocation unit size to use?

I know many people would say defaults but as a gamer/tech I have come to realize... defaults suck...

Before (like when XP first came out...) I just let it format with defaults... since then however I have come to customize everything... even now I notice a performance gain from my WD Raptor's when I use 64k unit allocation for OS Drive/Game Drive/Storage drive...

So i guess my reason for this post... Whats the best FileSystem/Allocation Unit size?

I have the following as options...
FAT32 - 512b/1024b/2048b/4096b/8192b/16384b/32768b/65536b
NTFS - 512b/1024b/2048b/4096b/8192b/16384b/32768b/65536b
exFAT - 512b/1024b/2048b/4096b/8192b/16384b/32768b/65536b/131072b/262144b/524288b/1048576b/2097152b/4194304b/8388608b/16777216b/33554432b

(exFAT threw me for a loop... i knew there was bigger then 64k allocation unit sizes but i didn't think it went that high... and especially for a 2gb flash drive... i formatted it with 32meg unit size for kicks and for 900megs on my 64k raptor it told me i needed 311GB more to transfer it to the flash drive... what a doozy...)

So what should i use? (also i should note that currently my flash drive... lags..i guess thats what ill call it... its really laggy, for any program that runs from it, im getting a GT Voyager drive... but i still want to know what i should use)

(- er figured i should figure this for those who dont know unit sizes... 512bytes/1kilobytes/2kilobytes/4kilobytes/8kilobytes/16kilobytes/32kilobytes/64kilobytes/128kilobytes/256kilobytes/512kilobytes/1megabyte/2megabytes/4megabytes/8megabytes/16megabytes/32megabytes -)

I also already know about exFAT only working with SP1 Vista and Server08 so thats not a problem for exFAT...

Last seen: 3 years 11 months ago
Joined: 2007-07-20 16:42
What size flash drive?

I'm not a guru, but what I've found is that you should choose the smallest cluster size you can. The answer also depends upon what size flash drive you are using. For example, if you've got a 2G drive, then you can use FAT, which would give a smaller cluster size than FAT32 on a larger drive.

Of course I could be wrong. Smile

RMB Fixed
Last seen: 12 years 11 months ago
Joined: 2006-10-24 10:30

Sorry for reviving this old thread but it's actually a very good question !
You should use exFAT if possible, it's practically designed for NAND-FLASH
and is also available for winXP now .
As for the cluster-size :On mechanical HDD's, cluster-size should be determined by the size of the files you want to store . If all your files are 4GB ISO's there's no point in selecting anything but the largest possible cluster-size . If all your files are 4KB, that's what you should select .. so the "optimal" cluster-size is actually hard to determine on a drive with files of different sizes and usually ends up being a compromise between overhead and performance ..

Obviously, Flash-drives don't work the same way as a electro-mechanical disk,
most importantly they don't really have tracks, sectors, clusters and all the other stuff you are used to from EM-HDD's.
Based on the little available information available f.eks here : &
..and from my own experiments, it seems that the way to go is to set the cluster-size equal to the block-size used by the device ..

Just a little background-info (from WIKI) on NAND & blocks :
"NAND flash architecture was introduced by Toshiba in 1989. These memories are accessed much like block devices such as hard disks or memory cards. Each block consists of a number of pages. The pages are typically 512 or 2,048 or 4,096 bytes in size. Associated with each page are a few bytes (typically 12–16 bytes) that should be used for storage of an error detection and correction checksum.

Typical block sizes include:

* 32 pages of 512 bytes each for a block size of 16 KB
* 64 pages of 2,048 bytes each for a block size of 128 KB
* 64 pages of 4,096 bytes each for a block size of 256 KB
* 128 pages of 4,096 bytes each for a block size of 512 KB

While reading and programming is performed on a page basis, erasure can only be performed on a block basis. Another limitation of NAND flash is data in a block can only be written sequentially. Number of Operations (NOPs) is the number of times the sectors can be programmed. So far this number for MLC flash is always one whereas for SLC flash it is four. "

Last seen: 11 years 10 months ago
Joined: 2006-12-12 12:00
Download IOzone and benchmark

Download IOzone and benchmark them.

"Those people who think they know everything are a great annoyance to those of us who do." Asimov

Last seen: 5 years 6 months ago
Joined: 2007-05-07 03:47
being that I have never used

being that I have never used IOzone before... and my flash driver is drive H...

wtf do i do? I read the instructions a bit but im still lost as all hell..

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