Raspberry Pi 3B+でzramを用いてメモリ拡張をやってみた際のメモ

            The zram module creates RAM based block devices named /dev/zram<id> (<id> = 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.
        

            $ ls /lib/modules/{カーネルで一番新しいバージョンのフォルダ}/kernel/drivers/block/zram
zram.ko
        

            curl -O http://sstea.blog.jp/raspi/script/zram.sh
        

            #!/bin/sh

###BEGIN INIT INFO
#Provides:       zram
#Required-Start:
#Required-Stop:
#Default-Start:  2 3 4 5
#Default-Stop:   0 1 6
###END INIT INFO

case "$1" in
    start)
        modprobe zram

        echo lz4 > /sys/block/zram0/comp_algorithm
        echo 256M > /sys/block/zram0/disksize

        mkswap /dev/zram0
        swapon -p 5 /dev/zram0
        ;;
    stop)
        swapoff /dev/zram0
        sleep 1
        modprobe -r zram
        ;;
    *)
        echo "Usage $0 start | stop "
        ;;
esac
        

            $ chmod 755 zram.sh
$ sudo mv zram.sh /etc/init.d/
$ sudo chkconfig --add zram.sh
        

            $ zramctl
NAME       ALGORITHM DISKSIZE  DATA COMPR TOTAL STREAMS MOUNTPOINT
/dev/zram0 lz4             2G  100M 45.2M 49.4M       4 [SWAP]
        

            $ swapon -s
Filename                Type        Size    Used    Priority
/dev/zram0                                 partition    2097148    103168    5
/var/swap                                  file        2097148    0    -2
        

            $ lsblk -p -l
NAME           MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
/dev/sda         8:0    1  7.6G  0 disk /media/pi/UDISK
/dev/sdb         8:16   1  1.7G  1 disk /media/pi/011E-AF76
/dev/mmcblk0   179:0    0 14.9G  0 disk 
/dev/mmcblk0p1 179:1    0  256M  0 part /boot
/dev/mmcblk0p2 179:2    0 14.6G  0 part /
/dev/zram0     254:0    0    2G  0 disk [SWAP]