| zram: Compressed RAM based block devices |
| ---------------------------------------- |
| |
| Project home: http://compcache.googlecode.com/ |
| |
| * Introduction |
| |
| The zram module creates RAM based block devices: /dev/ramX (X = 0, 1, ...). |
| Pages written to these disks are compressed and stored in memory itself. |
| These disks allow very fast I/O and compression provides good amounts of |
| memory savings. |
| |
| See project home for use cases, performance numbers and a lot more. |
| |
| Individual zram devices are configured and initialized using zramconfig |
| userspace utility as shown in examples below. See zramconfig man page for |
| more details. |
| |
| * Usage |
| |
| Following shows a typical sequence of steps for using zram. |
| |
| 1) Load Modules: |
| modprobe zram num_devices=4 |
| This creates 4 (uninitialized) devices: /dev/zram{0,1,2,3} |
| (num_devices parameter is optional. Default: 1) |
| |
| 2) Initialize: |
| Use zramconfig utility to configure and initialize individual |
| zram devices. For example: |
| zramconfig /dev/zram0 --init # uses default value of disksize_kb |
| zramconfig /dev/zram1 --disksize_kb=102400 # 100MB /dev/zram1 |
| |
| *See zramconfig man page for more details and examples* |
| |
| 3) Activate: |
| mkswap /dev/zram0 |
| swapon /dev/zram0 |
| |
| mkfs.ext4 /dev/zram1 |
| mount /dev/zram1 /tmp |
| |
| 4) Stats: |
| zramconfig /dev/zram0 --stats |
| zramconfig /dev/zram1 --stats |
| |
| 5) Deactivate: |
| swapoff /dev/zram0 |
| umount /dev/zram1 |
| |
| 6) Reset: |
| zramconfig /dev/zram0 --reset |
| zramconfig /dev/zram1 --reset |
| (This frees memory allocated for the given device). |
| |
| |
| Please report any problems at: |
| - Mailing list: linux-mm-cc at laptop dot org |
| - Issue tracker: http://code.google.com/p/compcache/issues/list |
| |
| Nitin Gupta |
| ngupta@vflare.org |
