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  1. #1

    64 GB microsd blksize 131072

    I don't know which forum this fits. I have a Samsung Galaxy Note II that I bought used a few months ago. It's stock rom and rooted. I recently noticed that if I run df it lists my external sd card has a blksize of 131072. That doesn't seem very efficient. Is it possible to format my microsd card with a smaller block size?

  2. #2
    root
    Join Date
    May 2011
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    506

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    Nexus 6P, HTC One M9
    You can reformat and specify the block size, but note the trade off is better performance with larger and less wasted space with smaller. With a 64G card you may want to lean toward better performance (unless you're close to filling the card).

    --jeremy



  3. #3
    Quote Originally Posted by TrickyRickinOK View Post
    I don't know which forum this fits. I have a Samsung Galaxy Note II that I bought used a few months ago. It's stock rom and rooted. I recently noticed that if I run df it lists my external sd card has a blksize of 131072. That doesn't seem very efficient. Is it possible to format my microsd card with a smaller block size?
    Your external card is probably formatted as FAT32. While it's possible to specify block size when formatting, using the /A:<size> parm, the format command normally uses defaults that are recommended.

    On a FAT file system, the smallest amount of disk accessible in a single read/write operation is a cluster. Each cluster must have a unique address. For FAT16 file systems, the address is stored in 16 bits, yielding 65,536 total clusters. Format can't create a cluster larger than 32K, so there's a 2GB volume size limit. FAT32 moved to a 32bit address, so the number of total clusters is 4177918, and cluster size will be the total space divided by the total number of clusters. (That works out to 16K for a 64GB drive.)

    Unless you are storing lots of tiny files on the card, you probably don't care. The sort of stuff people put on external cards like video and music files tends to be large, You won't have a lot of "slack" space with clusters only partially used.

    You can get more efficient space usage, but it requires using a different file system, and then you have the question of the device being able to use it. Linux ext2/3 might work. NTFS will require a driver. (Paragon Software has a free NTFS driver for Android, but it requires a rooted device to operate.)

    Personally, I don't think the effort would be worth doing.
    ______
    Dennis



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