For a raspberrypi image, mainly there are two partitions, kernel and rootfs. The size of kernel size is ~48M. Rootfs is mounted on SD card and its value can be increased using gparted,fdisk or similar tool. By default while flashing an image to SD card, two partitions are created, namely mmcblk0p1 and mmcblk0p2. rootfs image is stored in mmcblk0p2 whereas mmcblk0p1 holds boot information.
The details of sd card partions and its sizes can be found using "fdsik -l command"
root@raspberrypi-rdk-hybrid:~# fdisk -l
Disk /dev/mmcblk0: 14 GB, 15552479232 bytes, 30375936 sectors
474624 cylinders, 4 heads, 16 sectors/track
Units: sectors of 1 * 512 = 512 bytes Device Boot StartCHS EndCHS StartLBA EndLBA Sectors Size Id Type
/dev/mmcblk0p1 * 64,0,1 841,0,32 8192 107679 99488 48.5M c Win95 FAT32 (LBA)
/dev/mmcblk0p2 896,0,1 1023,3,32 114688 10711039 10596352 5174M 83 Linux
root@raspberrypi-rdk-hybrid:~# |
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For changing sd card partition using gparted refer below link.
Partioning and Resizing using GParted GUI
Memory Usage
The memory in raspberrypi is partitioned into different sessions and the details of these partitions and allocated size for these partitions can be found out using df command. df -h command gives size allocated to each of these partitions and the size that is already used by different components.
root@raspberrypi-rdk-hybrid:~# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 865.5M 552.0M 252.0M 69% /
devtmpfs 339.6M 0 339.6M 0% /dev
tmpfs 468.1M 8.0K 468.1M 0% /dev/shm
tmpfs 194.3M 8.8M 185.6M 5% /run
tmpfs 468.1M 0 468.1M 0% /sys/fs/cgroup
tmpfs 468.1M 6.6M 461.5M 1% /tmp
tmpfs 468.1M 6.6M 461.5M 1% /etc/snmp/snmpd.conf
tmpfs 468.1M 236.0K 467.9M 0% /var/volatile
/dev/root 865.5M 552.0M 252.0M 69% /var/lib
/dev/mmcblk0p1 48.5M 27.4M 21.0M 57% /boot
tmpfs 93.6M 0 93.6M 0% /run/user/0
root@raspberrypi-rdk-hybrid |
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The total amount of RAM memory used and the available memory can be found using free command. free -lh command gives the details of the amount of memory used out of the total memory and the available memory that can be used for functions like audio/video playback.
root@raspberrypi-rdk-hybrid:~# free -lh
total used free shared buff/cache available
Mem: 936M 571M 217M 26M 147M 311M
Low: 936M 718M 217M
High: 0B 0B 0B
Swap: 0B 0B 0B
root@raspberrypi-rdk-hybrid:~# |
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Boot memory Information
The memory allocated for each component at the time of boot up is given below.
| Component | Size |
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| Kernel code | 9216K |
| RW data | 737K |
| RO data | 2928K |
| init | 1024K |
| BSS | 853K |
| vmalloc | 1097K |
| cma total | 262K |
| KernelStack | 2536 kB |
| Shmem | 14596 kB |
Graphics memory
Graphics memory, commonly called GPU memory is the amount of memory available on graphics card and is used by graphics processor. We can use vcgencmd for getting gpu memory information.
Please refer below link for GPU memory details.
GPU Memory Consumption Analysis
root@raspberrypi-rdk-hybrid:~# vcgencmd get_mem gpu
gpu=64M |
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Changing tmpfs partition size
Size of tmpfs partition can be changed by using fstab. Below are the list of tmpfs partitions.
tmpfs 468.1M 4.0K 468.1M 0% /dev/shm
tmpfs 194.3M 8.8M 185.5M 5% /run
tmpfs 468.1M 0 468.1M 0% /sys/fs/cgroup
tmpfs 468.1M 2.2M 466.0M 0% /tmp
tmpfs 468.1M 2.2M 466.0M 0% /etc/snmp/snmpd.conf
tmpfs 468.1M 320.0K 467.8M 0% /var/volatile |
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The size of these partitions can be changed by mentioning size in /etc/fstab. For example, we reduce size of /run to ~100M by mentioning size as below. Reboot the device after fstab is modified.
root@raspberrypi-rdk-hybrid:~# vi /etc/fstab
# stock fstab - you probably want to override this with a machine specific one /dev/root / auto defaults 1 0
proc /proc proc defaults 0 0
devpts /dev/pts devpts mode=0620,ptmxmode=0666,gid=5 0 0
tmpfs /run tmpfs mode=0755,nodev,nosuid,strictatime,size=103741824 0 0
tmpfs /var/volatile tmpfs defaults 0 0 # uncomment this if your device has a SD/MMC/Transflash slot
#/dev/mmcblk0p1 /media/card auto defaults,sync,noauto 0 0 /dev/mmcblk0p1 /boot vfat defaults 0 0 |
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The changed size can be verified using df command. The above change results in
root@raspberrypi-rdk-hybrid:~# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 865.5M 557.0M 247.0M 69% /
devtmpfs 339.6M 0 339.6M 0% /dev
tmpfs 468.1M 8.0K 468.1M 0% /dev/shm
tmpfs 98.9M 8.8M 90.2M 9% /run
tmpfs 468.1M 0 468.1M 0% /sys/fs/cgroup
tmpfs 468.1M 6.6M 461.5M 1% /tmp
tmpfs 468.1M 6.6M 461.5M 1% /etc/snmp/snmpd.conf
tmpfs 468.1M 428.0K 467.7M 0% /var/volatile
/dev/root 865.5M 557.0M 247.0M 69% /var/lib
/dev/mmcblk0p1 48.5M 27.4M 21.0M 57% /boot
tmpfs 93.6M 0 93.6M 0% /run/user/0 |
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