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SanDisk User
Posts: 57
Registered: ‎04-24-2019

Re: Storage size on Extreme Portable SSD unusually large. 25 times larger than total file sizes


@larryg92 wrote:

One thing I forgot to mention was that I chose 512 byte cluster size because of the small size of the most of the files I am storing on the drive.  You'll get better performance with a larger cluster size which would be better for media files like large video files at the cost of losing some file space. Not as much as the default Sandisk cluster size. As you can tell I'm not an expert but it worked for me. 


the file size should not be different even to the extent of 3 time larger. Something is not right. How are you copying the files? Are the files compressed on the HDD? 

 
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SanDisk User
Posts: 57
Registered: ‎04-24-2019

Re: Storage size on Extreme Portable SSD unusually large. 25 times larger than total file sizes

[ Edited ]

@BRITANY wrote:

@larryg92 wrote:

One thing I forgot to mention was that I chose 512 byte cluster size because of the small size of the most of the files I am storing on the drive FileZilla UC Browser Rufus You'll get better performance with a larger cluster size which would be better for media files like large video files at the cost of losing some file space. Not as much as the default Sandisk cluster size. As you can tell I'm not an expert but it worked for me. 


the file size should not be different even to the extent of 3 time larger. Something is not right. How are you copying the files? Are the files compressed on the HDD? 

 

One thing I forgot to mention was that I chose 512 byte cluster size because of the small size of the most of the files I am storing on the drive.  You'll get better performance with a larger cluster size which would be better for media files like large video files at the cost of losing some file space. Not as much as the default Sandisk cluster size. As you can tell I'm not an expert but it worked for me. 

Newbie
Posts: 1
Registered: ‎10-11-2019

Re: Storage size on Extreme Portable SSD unusually large. 25 times larger than total file sizes

[ Edited ]

I Windows Explorer, right-clicking a file or folder and choosing Properties will show the nominal size as well as the disk size.

 

I believe a cluster size / allocation unit of e.g. 1024 KB mens all files will take up at least this much space on disk each (and e.g. a file of nominal size 1025 KB will take up 2048 KB, disk size). So a file of 1 byte (0.001 KB, extreme lower limit) will take up about a million times as much space on disk (extreme upper limit). A short Word document of e.g. 20 KB will take up 50 times as much; a medium resolution photo of e.g. 200 KB will take up 5 times as much.

On my SanDisk the allocation unit is 1024 KB; I'm not sure but I think that is how it came - and it certainly annoys me now. The SSD drive on my laptop has allocation unit 4 KB, meaning the disk space used for each small file is much much smaller.

 

I suppose a large allocation unit leads to better speed performance for large files, so the best choice of allocation unit is a compromise. Perhaps there are also design choices made when building an SSD that mean it will work best with a certain allocation unit - I do not know.

 

I suppose the only way to change the allocation unit is through formatting the drive, so I suppose you'll need some other place to keep your files meanwhile.