I need a block device in RAM. I built a 3.x kernel and added the RAM block device driver. The number of RAM block device drive is 16 (by default) but when the kernel boots there is no ramx in
/dev. What's going on?
I think you mean something like this:
Load the block ramdisk module, set the desired size in blocks using the
# modprobe brd rd_size=123456
...after this step
You now can put a filesystem on it.
# mkfs /dev/ram0 mke2fs 1.41.12 (17-May-2010) Filesystem label= OS type: Linux Block size=1024 (log=0) Fragment size=1024 (log=0) Stride=0 blocks, Stripe width=0 blocks 30976 inodes, 123456 blocks 6172 blocks (5.00%) reserved for the super user First data block=1 Maximum filesystem blocks=67371008 16 block groups 8192 blocks per group, 8192 fragments per group 1936 inodes per group Superblock backups stored on blocks: 8193, 24577, 40961, 57345, 73729 Writing inode tables: done Writing superblocks and filesystem accounting information: done This filesystem will be automatically checked every 38 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override.
Mount it and check the space used and free...
# mount /dev/ram0 /mnt # df /mnt Filesystem 1K-blocks Used Available Use% Mounted on /dev/ram0 119539 1550 111817 2% /mnt