Easy Installer partition size

Technical Support
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1

I want Easy Installer to create a partition of exactly 1536MB. My json file looks like that:

"want_maximised": false,
"content": {
           "uncompressed_size": 410,
           "mkfs_options": "",
           "filename": "rootfs.tar.xz",
           "filesystem_type": "ext3",
           "label": "RFS"
},
"partition_size_nominal": 1536

but however, after installation the partition has a size of 1515376 1K-blocks which is less then i would expect (1572864 1K-blocks).
I am asking this question because i want the exactly same memory layout like in my mbr.bin file that was created with oe-core.

2

Hi

I guess you don’t compare the same numbers.

With ‘partition_size_nominal’ you specify the partitionsize for the filesystem to live in.
But with ‘df’ (which you likely used to query the size) you get the the filesystem size.

There is a difference between the meaning of the two numbers as the file system sets aside blocks for its journalling (and maybe other stuff). Additionally a filesystem would not necessarily use the full size of a partition.

So I guess if you compare the resulting partitioning with the configured one there is no discrepancy any more. i.e. use fdisk to check the ‘Blocks’ field for the partition in question.

root@apalis-imx6:~# fdisk /dev/mmcblk0                                          
                                                                                
The number of cylinders for this disk is set to 120832.                         
There is nothing wrong with that, but this is larger than 1024,                 
and could in certain setups cause problems with:                                
1) software that runs at boot time (e.g., old versions of LILO)                 
2) booting and partitioning software from other OSs                             
   (e.g., DOS FDISK, OS/2 FDISK)                                                
                                                                                
Command (m for help): u                                                         
Changing display/entry units to sectors                                         
                                                                                
Command (m for help): p                                                         
                                                                                
Disk /dev/mmcblk0: 3959 MB, 3959422976 bytes                                    
4 heads, 16 sectors/track, 120832 cylinders, total 7733248 sectors              
Units = sectors of 1 * 512 = 512 bytes                                          
                                                                                
        Device Boot      Start         End      Blocks  Id System               
/dev/mmcblk0p1            8192       40959       16384   c Win95 FAT32 (LBA)    
/dev/mmcblk0p2           40960     3186687     1572864  83 Linux                
/dev/mmcblk0p3         3186688     7733247     2273280  83 Linux

Max