# Customize

This section explains how to customize the storage features including adding a new partition and mounting the SD card to a specific path.

##  File system  

ext4 is an open-source file system that is used on data partitions on the Qualcomm Linux platform.

ext4 is a [journaling file system](https://en.wikipedia.org/wiki/Journaling_file_system) ![arrow-ext](data:image/png;base64,UklGRt4AAABXRUJQVlA4TNIAAAAvD8ADED/BoG0jSe5SXP5I7gkNRG3byLnX4Tn+2K4I2raNw5/iqPxlEwBAGlwuj8BNBPpnsblrANx3P36s+DHQIcQ0dmEfEGPc8WEcCCcO/M2hXv3rDJTcHCTB1es7l9P2UoywA2a3jSW/pp77EhxGkq1E8zjH3R3e/fxjREOI6P8EcH+lqu/oTK/6kS+YwlHVAMjkP0ErP1UNIZZmnsB32Y2lZjNPO7HUUA1HkVWz73lAIiWM6WaegFcHzNOJ3bv89WhdNu1TDx/txhT2np2bzWU=) for Linux. The ext4 file system can support volumes with sizes in theory up to 64ZB and single files with sizes up to 16TB with the standard 4KB block size.

An extent is a range of contiguous physical blocks, improving large-file performance and reducing fragmentation. A single extent in ext4 can map up to 128 MiB of contiguous space with a 4 KB block size.

ext4 does not limit the number of subdirectories in a single directory, except by the inherent size limit of the directory itself.

For more information, see [An introduction to Linux’s EXT4 filesystem | Opensource.com](https://opensource.com/article/17/5/introduction-ext4-filesystem) ![arrow-ext](data:image/png;base64,UklGRt4AAABXRUJQVlA4TNIAAAAvD8ADED/BoG0jSe5SXP5I7gkNRG3byLnX4Tn+2K4I2raNw5/iqPxlEwBAGlwuj8BNBPpnsblrANx3P36s+DHQIcQ0dmEfEGPc8WEcCCcO/M2hXv3rDJTcHCTB1es7l9P2UoywA2a3jSW/pp77EhxGkq1E8zjH3R3e/fxjREOI6P8EcH+lqu/oTK/6kS+YwlHVAMjkP0ErP1UNIZZmnsB32Y2lZjNPO7HUUA1HkVWz73lAIiWM6WaegFcHzNOJ3bv89WhdNu1TDx/txhT2np2bzWU=)

Data partition is mounted at `/mnt/overlay`.

For example:

/dev/sda9 on /mnt/overlay type ext4 (rw,relatime,rootcontext=system_u:object_r:etc_t:s0,seclabel,stripe=128,inlinecrypt)
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To mount `/dev/sda9` to `/data` use the following commands:

/ # mkdir /home/root/data
    / # mount -o rw,remount /
    / # mount -t ext4 /dev/sda9 /home/root/data
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Note

If you encounter any issues related to SELINUX, please use the following command.

mount -o rootcontext=system_u:object_r:etc_t:s0 -t ext4 /dev/sda9 /home/root/data
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Execute the `mount` command to retrieve the exact `rootcontext=<>` value related to the `/mnt/overlay`.

##  Mount the SD card to a specific path 

If the SD card is not mounting automatically, please use the following commands to manually remount it to a specific path.

1. Remount the root partition as read-write:

sh-5.1# mount -o rw,remount /
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2. Create an SD card directory:

sh-5.1# mkdir sdcard
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3. Check the default path where we created this SD card directory:

root@qcs6490-rb3gen2-vision-kit:~# pwd
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    This will print the default path to the terminal:

/home/root (<-- this is the default path)Copy to clipboard
4. Mount the SD card to the previously created path (`/sdcard`):

sh-5.1# mount -t vfat /dev/mmcblk1p1 /<default_path>/sdcard
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5. To verify whether the SD card is mounted, check the available space using:

sh-5.1# df -h
        ..
        /dev/mmcblk1p1 7.4G 101M 7.4G 2% /<default_path>/sdcard
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Note

If the SD card has multiple partitions, follow step 4 to mount each partition.

##  Preferred vendor list (PVL) memory part information 

All UFS parts supported on the Qualcomm SoC are qualified in the PVL validation. Select the applicable part from the [Memory list](https://www.qualcomm.com/products/internet-of-things/industrial/building-enterprise/qcs6490/peripherals).

Last Published: Oct 02, 2024

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