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本次的开拓板上核心板型号是MYC-YA151C-256N256D-65-I-T，以是从系统中可以看到NAND的分区情形
dev: size erasesize namemtd0: 00200000 00020000 "fsbl"mtd1: 00200000 00020000 "ssbl1"mtd2: 00200000 00020000 "ssbl2"mtd3: 0fa00000 00020000 "UBI"前面三个是FSBL和两个SSBL，那么就能确定，kernel, dtb, rootfs该当都在UBI分区里面。接下来看下UBI分区里的信息
可以看出有四个volume，分别是0,1,2,3。那就依次看下这几个卷
（图片来自网络侵删）
可以看出来，vol2是boot，vol3是rootfs。以是从mount命令也可以看出来
root@myir-ya151c-t:~# mountubi0:rootfs on / type ubifs (rw,relatime,assert=read-only,ubi=0,vol=3)devtmpfs on /dev type devtmpfs (rw,relatime,size=54648k,nr_inodes=13662,mode=755)sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)proc on /proc type proc (rw,relatime)securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)devpts on /dev/pts type devpts (rw,relatime,gid=5,mode=620,ptmxmode=000)tmpfs on /run type tmpfs (rw,nosuid,nodev,mode=755)tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755)cgroup2 on /sys/fs/cgroup/unified type cgroup2 (rw,nosuid,nodev,noexec,relatime,nsdelegate)cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,name=systemd)pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)none on /sys/fs/bpf type bpf (rw,nosuid,nodev,noexec,relatime,mode=700)cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpu,cpuacct)cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,net_cls,net_prio)cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)mqueue on /dev/mqueue type mqueue (rw,nosuid,nodev,noexec,relatime)debugfs on /sys/kernel/debug type debugfs (rw,nosuid,nodev,noexec,relatime)tmpfs on /tmp type tmpfs (rw,nosuid,nodev)fusectl on /sys/fs/fuse/connections type fusectl (rw,nosuid,nodev,noexec,relatime)configfs on /sys/kernel/config type configfs (rw,nosuid,nodev,noexec,relatime)/dev/ubi0_2 on /boot type ubifs (rw,relatime,assert=read-only,ubi=0,vol=2)tmpfs on /var/volatile type tmpfs (rw,relatime)tmpfs on /run/user/0 type tmpfs (rw,nosuid,nodev,relatime,size=24136k,mode=700)至于0和1，后面来剖析。当前配置是nand 256MB的，看下系统还剩下多少空间可以利用
root@myir-ya151c-t:~# df -hFilesystem Size Used Avail Use% Mounted onubi0:rootfs 201M 177M 25M 88% /devtmpfs 54M 0 54M 0% /devtmpfs 118M 64K 118M 1% /dev/shmtmpfs 118M 8.8M 110M 8% /runtmpfs 118M 0 118M 0% /sys/fs/cgrouptmpfs 118M 0 118M 0% /tmp/dev/ubi0_2 15M 11M 3.4M 77% /boottmpfs 118M 136K 118M 1% /var/volatiletmpfs 24M 0 24M 0% /run/user/0已经被利用了88%，以是只有25MB可以利用，也运行不了多少运用了。对付利用nand来作为产品开拓，还须要更深度的对系统优化，后面有韶光可以做这方面看看。再看看ram的利用情形
root@myir-ya151c-t:~# freetotal used free shared buff/cache availableMem: 241392 55156 129216 9120 57020 171316Swap: 0 0 0统共256MB，系统占用后，剩余可以利用的只有130MB旁边。那就再看下当前系统默认运行了哪些运用
root@myir-ya151c-t:~# ps -efUID PID PPID C STIME TTY TIME CMDroot 1 0 0 15:50 ? 00:00:05 /sbin/initroot 2 0 0 15:50 ? 00:00:00 [kthreadd]root 3 2 0 15:50 ? 00:00:00 [rcu_gp]root 4 2 0 15:50 ? 00:00:00 [rcu_par_gp]root 6 2 0 15:50 ? 00:00:00 [kworker/0:0H-events_highpri]root 7 2 0 15:50 ? 00:00:00 [kworker/u2:0-events_unbound]root 8 2 0 15:50 ? 00:00:00 [mm_percpu_wq]root 9 2 0 15:50 ? 00:00:01 [ksoftirqd/0]root 10 2 0 15:50 ? 00:00:00 [rcu_preempt]root 11 2 0 15:50 ? 00:00:00 [migration/0]root 12 2 0 15:50 ? 00:00:00 [cpuhp/0]root 13 2 0 15:50 ? 00:00:00 [kdevtmpfs]root 14 2 0 15:50 ? 00:00:00 [netns]root 15 2 0 15:50 ? 00:00:00 [rcu_tasks_kthre]root 16 2 0 15:50 ? 00:00:06 [kworker/0:1-pm]root 17 2 0 15:50 ? 00:00:00 [oom_reaper]root 18 2 0 15:50 ? 00:00:00 [writeback]root 19 2 0 15:50 ? 00:00:00 [kcompactd0]root 87 2 0 15:50 ? 00:00:00 [kblockd]root 88 2 0 15:50 ? 00:00:00 [blkcg_punt_bio]root 89 2 0 15:50 ? 00:00:00 [ata_sff]root 90 2 0 15:50 ? 00:00:00 [edac-poller]root 91 2 0 15:50 ? 00:00:00 [devfreq_wq]root 92 2 0 15:50 ? 00:00:00 [watchdogd]root 93 2 0 15:50 ? 00:00:00 [rpciod]root 94 2 0 15:50 ? 00:00:00 [kworker/u3:0-hci0]root 95 2 0 15:50 ? 00:00:00 [xprtiod]root 96 2 0 15:50 ? 00:00:00 [kswapd0]root 97 2 0 15:50 ? 00:00:00 [nfsiod]root 98 2 0 15:50 ? 00:00:00 [cifsiod]root 99 2 0 15:50 ? 00:00:00 [smb3decryptd]root 100 2 0 15:50 ? 00:00:00 [cifsfileinfoput]root 101 2 0 15:50 ? 00:00:00 [cifsoplockd]root 106 2 0 15:50 ? 00:00:00 [krfcommd]root 107 2 0 15:50 ? 00:00:00 [kstrp]root 118 2 0 15:50 ? 00:00:00 [hwrng]root 119 2 0 15:50 ? 00:00:00 [irq/45-stm_ther]root 124 2 0 15:50 ? 00:00:00 [irq/46-54002000]root 125 2 0 15:50 ? 00:00:00 [54002000.hash-e]root 143 2 0 15:50 ? 00:00:00 [irq/59-5c004000]root 144 2 0 15:50 ? 00:00:00 [irq/60-40013000]root 145 2 0 15:50 ? 00:00:00 [irq/65-5c002000]root 146 2 0 15:50 ? 00:00:00 [irq/67-pmic_irq]root 150 2 0 15:50 ? 00:00:00 [irq/77-4c001000]root 151 2 0 15:50 ? 00:00:00 [irq/78-4c001000]root 152 2 0 15:50 ? 00:00:00 [mlahb:m4@100000]root 154 2 0 15:50 ? 00:00:00 [irq/80-48003000]root 155 2 0 15:50 ? 00:00:00 [irq/81-48003000]root 156 2 0 15:50 ? 00:00:00 [stmmac_wq]root 158 2 0 15:51 ? 00:00:00 [irq/63-0-0028]root 159 2 0 15:51 ? 00:00:00 [ubi_bgt0d]root 161 2 0 15:51 ? 00:00:00 [ubifs_bgt0_3]root 162 2 0 15:51 ? 00:00:00 [ipv6_addrconf]root 618 1 2 15:51 ? 00:00:35 /usr/sbin/rngd -f -r /dev/hwrngrpc 622 1 0 15:51 ? 00:00:00 /usr/sbin/rpcbind -w -froot 629 1 0 15:51 ? 00:00:00 /lib/systemd/systemd-journaldroot 638 2 0 15:51 ? 00:00:00 [ubifs_bgt0_2]root 652 1 0 15:51 ? 00:00:00 /lib/systemd/systemd-udevdsystemd+ 656 1 0 15:51 ? 00:00:01 /lib/systemd/systemd-timesyncdroot 670 2 0 15:51 ? 00:00:00 [irq/22-44009000]root 671 2 0 15:51 ? 00:00:00 [spi0]root 688 1 0 15:51 ? 00:00:00 /sbin/klogd -nroot 692 1 0 15:51 ? 00:00:00 /sbin/syslogd -nmessage+ 698 1 0 15:51 ? 00:00:00 /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation --syslog-onlyroot 725 2 0 15:51 ? 00:00:00 [irq/42-4c006000]root 726 2 0 15:51 ? 00:00:00 [irq/57-5c000000]root 727 2 0 15:51 ? 00:00:00 [kworker/u2:2-events_unbound]root 730 2 0 15:51 ? 00:00:00 [kworker/u3:2-hci0]root 769 1 0 15:51 ? 00:00:00 /lib/systemd/systemd-logindroot 770 1 0 15:51 ? 00:00:00 /usr/libexec/bluetooth/bluetoothdsystemd+ 771 1 0 15:51 ? 00:00:01 /lib/systemd/systemd-networkdroot 773 1 1 15:51 ? 00:00:17 /usr/sbin/netdata -D -u rootsystemd+ 778 1 0 15:51 ? 00:00:00 /lib/systemd/systemd-resolvedavahi 779 1 0 15:51 ? 00:00:00 avahi-daemon: running [myir-ya151c-t.local]root 780 1 0 15:51 ? 00:00:00 /usr/sbin/iiod64371 781 1 0 15:51 ? 00:00:00 /sbin/ninfod -davahi 782 779 0 15:51 ? 00:00:00 avahi-daemon: chroot helperpulse 784 1 0 15:51 ? 00:00:00 /usr/bin/pulseaudio --system --realtime --disallow-exit --daemonize=no61563 785 1 0 15:51 ? 00:00:00 /sbin/rdisc -f -troot 787 1 0 15:51 ? 00:00:00 /usr/sbin/vsftpdroot 790 1 0 15:51 tty1 00:00:00 /sbin/agetty -o -p -- \u --noclear tty1 linuxroot 791 1 0 15:51 ttySTM0 00:00:00 /bin/login -froot 794 2 0 15:51 ? 00:00:00 [irq/55-40010000]root 796 1 0 15:51 ? 00:00:00 /lib/systemd/systemd --userroot 797 796 0 15:51 ? 00:00:00 (sd-pam)root 802 791 0 15:51 ttySTM0 00:00:00 -shroot 807 1 0 15:51 ? 00:00:00 /usr/bin/dbus-daemon --syslog --fork --print-pid 4 --print-address 6 --sessionroot 815 1 0 15:51 ? 00:00:00 /usr/bin/dbus-daemon --syslog --fork --print-pid 4 --print-address 6 --sessionroot 823 1 0 15:51 ? 00:00:00 /usr/bin/dbus-daemon --syslog --fork --print-pid 4 --print-address 6 --sessionroot 839 2 0 15:51 ? 00:00:00 [kworker/0:1H]root 869 773 2 15:51 ? 00:00:31 /usr/libexec/netdata/plugins.d/apps.plugin 2root 871 773 0 15:51 ? 00:00:08 bash /usr/libexec/netdata/plugins.d/charts.d.plugin 2root 873 773 0 15:51 ? 00:00:05 /usr/bin/python3 /usr/libexec/netdata/plugins.d/python.d.plugin 2root 1043 2 0 15:52 ? 00:00:00 [cfg80211]root 1547 2 0 15:57 ? 00:00:10 [kworker/0:0+events_freezable]root 2057 2 0 16:05 ? 00:00:02 [kworker/0:2-events]root 2379 2 0 16:10 ? 00:00:02 [kworker/0:3-events]root 2688 2 0 16:15 ? 00:00:00 [kworker/0:4-events]看到有个netdata的python运用在运行，可以关闭看看能节省多少ram出来，其他的bluetooth，ftp不须要的也可以关闭，毕竟板上也没有这些硬件外设。
root@myir-ya151c-t:~# systemctl stop netdataroot@myir-ya151c-t:~# systemctl stop bluetooth关闭后有20MB，还是有一些优化的空间。
