jerrycc's notes

1. Prepare a USB disk consisting of 3 empty partitions: > lsblk ... sdb               8:16   1  28.9G  0 disk  ├─sdb1            8:17   1   500M  0 part  ├─sdb2            8:18   1   600M  0 part  └─sdb3            8:19   1   700M  0 part  2. Create physical volumes (pv) for each one of the partitions: > sudo pvcreate /dev/sdb{1,2,3}   Physical volume "/dev/sdb1" successfully created.   Physical volume "/dev/sdb2" successfully created.   Physical volume "/dev/sdb3" successfully created. 3. Verify the creation with pvscan: >sudo pvscan  PV /dev/sda7   VG centos          lvm2 [96.65 GiB / 4.00 MiB free]   PV /dev/sdb1                      lvm2 [500.00 MiB]   PV /dev/sdb3                      lvm2 [700.00 MiB]   PV /dev/sdb2                      lvm2 [600.00 MiB]   Total: 4 [98.41 GiB] / in use: 1 [96.65 GiB] / in no VG: 3 [<1.76 GiB] 3. Create a volume group (vg) consisting 2 physical volumes: > sudo

1. Prepare an USB key. 2. Copy the iso to the USB with dd command: [Warning!!] This will overwrite all the existing data on the disk. > sudo dd if=CentOS-7-x86_64-DVD-1708.iso of= /dev/sdb bs=1M status=progress 4519362560 bytes (4.5 GB) copied, 906.896074 s, 5.0 MB/s     ... (wait) 4312+0 records in 4312+0 records out 4521459712 bytes (4.5 GB) copied, 1240.27 s, 3.6 MB/s Note: Set the output stream to /dev/sd x  instead of /dev/sdb x . 3. Verfiy with fdisk > sudo fdisk -l ... Disk /dev/sdb : 31.0 GB, 30998003712 bytes, 60542976 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk label type: dos Disk identifier: 0x1302a8b3    Device Boot      Start         End      Blocks   Id  System /dev/sdb1   *           0     8830975     4415488    0  Empty /dev/sdb2            2320       20295        8988   ef  EFI (FAT-12/16/32) ... 4. Reboot the compute

To mount a partition to the filesystem on boot, go to the filesystem table file and append the corresponding instructions. Here is an example of fstab where I attached a Windows NTFS partition to /mnt/WinData during boot: # # /etc/fstab # Created by anaconda on Sun Sep 24 19:33:26 2017 # # Accessible filesystems, by reference, are maintained under '/dev/disk' # See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info # /dev/mapper/centos-root                   /               xfs   defaults  0 0 UUID=f55d96a4-bb64-4a91-9420-11c0ddaa525a /boot           xfs   defaults  0 0 /dev/mapper/centos-home                   /home           xfs   defaults  0 0 /dev/mapper/centos-swap                   swap            swap  defaults  0 0 UUID=FE56AF9056AF486B                     /mnt/WinData    ntfs  defaults  0 0 For more information: 鳥哥的私房菜 7.4 設定開機掛載 http://linux.vbird.org/linux_basic/0230filesystem.php#fstab or Search for "fstab"

Warning: this is a private study note only. There is no guarantee of the correctness of the contents.  1. prepare a USB pen drive 2. check its label with lsblk [jerry@jerrycc_laptop ~]$ lsblk NAME            MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT sda               8:0    0 465.8G  0 disk ├─sda1            8:1    0   200M  0 part ... sdb               8:16   1   1.9G  0 disk  3.  Create new partition with  fdisk : For example, you'll get a partition called /dev/sdb1 4. Format the partition with LUKS format: > sudo cryptsetup -y luksFormat /dev/sdb1  5. Open the partition and create the name for the mapper: > sudo cryptsetup luksOpen /dev/sdb1 myEncryptDisk 6. Format the partition with regular file system formats: Note that you have to find the partition in the device mapper directory > ls -al /dev/mapper/ lrwxrwxrwx.  1 root root       7  1月 16 23:16 myEncryptDisk -> ../dm-3 Then you format the partition with specific file system chosen (ext4

今天在嘗試用 mkfs 格式化一顆 flash drive 時，發現不管怎樣都會顯示下列訊息。 [jerry@jerrycc_laptop ~]$ sudo mkfs.ext4 /dev/sdb1 mke2fs 1.42.9 (28-Dec-2013) /dev/sdb1 is apparently in use by the system; will not make a filesystem here! 後來使用 lsblk 掃描，發現之前曾對它做過RAID的設定。 [jerry@jerrycc_laptop ~]$ lsblk NAME            MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT ... sdb               8:16   1   1.9G  0 disk   ├─sdb1            8:17   1     1G  0 part   │ └─md127         9:127  0   885M  0 raid1  └─sdb2            8:18   1   886M  0 part     └─md127         9:127  0   885M  0 raid1  求助 Google 大神後，發現有位老外好心幫我們找到解法 Unable to format drive - "is apparently in use by the system" 就是要用 mdadm 工具，將原本的 RAID 功能拿掉。 後來就能成功格式化了！ 最後修改：14 Jan 2018