To create sub directories even if the parent directories dont exist:
$ mkdir -p /tmp/foo/bar/this/dir
To create multiple directories with one command, to achieve:
/disk1/ebooks/category-tech
/disk1/ebooks/category-motivation
/disk2/ebooks/category-tech
/disk2/ebooks/category-motivation
/disk3/ebooks/category-tech
/disk3/ebooks/category-motivation
You can do:
mkdir -p /disk{1..5}/ebooks/category-{tech,motivation}
To check disk space:
$ df -hTo see the size of consumption per directory:
$ du -sh /path/to/dirs/*To view disk and sata input mappings: (0 is port 1)
$ lsblk -o NAME,MODEL,SERIAL,WWN,HCTL
NAME MODEL SERIAL WWN HCTL
sda ST4000D0000-000000 XXXXXXXX 0x5000c50000000000 0:0:0:0
sdb ST4000D0000-000000 XXXXXXXX 0x5000c50000000000 1:0:0:0
└─sdb1 0x5000c50000000000
sdc ST4000D0000-000000 XXXXXXXX 0x5000c50000000000 2:0:0:0
└─sdc1 0x5000c50000000000This scenario is when a disk cannot be unmounted, usually this is because the disk is still in use with another application:
umount /data
umount: /data: target is busy.Use the lsof (list open files) command to find out which processes are using the /data directory. Run sudo lsof /data. This will list all processes accessing files in /data.
sudo lsof /data
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
sudo 21204 root cwd DIR 259,3 4096 27525121 /data/tmp
bash 28594 root cwd DIR 259,3 4096 27525121 /data/tmpIn this scenario there was a shell session that was changed to that directory, we can either kill the pid (kill 28594) or jump to that session and exit the directory.
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Free memory is the amount of memory which is currently not used for anything. This number should be small, because memory which is not used is simply wasted.
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Available memory is the amount of memory which is available for allocation to a new process or to existing processes.
Difference between vsz and rss:
The Virtual Set Size is a memory size assigned to a process ( program ) during the initial execution. The Virtual Set Size memory is simply a number of how much memory a process has available for its execution.
As oppose to VSZ ( Virtual Set Size ), RSS is a memory currently used by a process. This is a actual number in kilobytes of how much RAM the current process is using.
Using ps to sort by memory usage:
$ ps aux --sort -rss
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 2124 0.1 11.4 422028 232864 ? Ssl Mar19 0:35 /bin/thanos
Using /proc/meminfo:
$ cat /proc/meminfo
MemTotal: 16424260 kB
MemFree: 173988 kB
MemAvailable: 13493104 kB
Buffers: 253116 kB
Cached: 12950152 kB
Using vmstat:
$ vmstat -s
16424260 K total memory
2598624 K used memory
3701676 K active memory
11821540 K inactive memory
328008 K free memory
253208 K buffer memory
13244420 K swap cache
Using top:
$ top -n 1 -b
top - 07:50:06 up 13 days, 22:22, 1 user, load average: 0.06, 0.07, 0.02
Tasks: 124 total, 1 running, 73 sleeping, 0 stopped, 0 zombie
%Cpu(s): 2.0 us, 0.4 sy, 0.0 ni, 97.3 id, 0.0 wa, 0.0 hi, 0.2 si, 0.0 st
KiB Mem : 16424260 total, 249368 free, 2597924 used, 13576968 buff/cache
KiB Swap: 0 total, 0 free, 0 used. 13490404 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
15482 user 20 0 7949520 2.150g 24408 S 37.5 13.7 40:35.70 java
More info on above:
%MEM is directly related to RES, it’s the percentage use of total physical memory by the process.
VIRT is the total memory that this process has access to shared memory, mapped pages, swapped out pages, etc.
RES is the total physical memory used shared or private that the process has access to.
SHR is the total physical shared memory that the process has access to.
Get memory stats:
$ wget https://raw.githubusercontent.com/pixelb/ps_mem/master/ps_mem.py
$ sudo python ps_mem.py
$ sudo chmod 755 /disk
$ sudo chown -R ubuntu:ubuntu /disk
$ sudo find /disk/2/htpc -type f -print -exec chmod 644 {} \;
$ sudo find /disk/2/htpc -type d -print -exec chmod 755 {} \;