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Add a disk to linux LVM command line

Linux Systems Guides
  • If your starting from scratch, ‘imaging’ or installing linux , insure you’ve partitioned with setup LVM on the first disk for this guide. As this is just the basic setup.

    Once you’ve reached the command line, you can run lsblk to list all block devices, noticing what is a partition and what is a device, where sda would be a device, and sda1 would be a partition:

    lsblk
    

    Output:

    NAME                 MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
    sda                    8:0    0 465.8G  0 disk 
    ├─sda1                 8:1    0   243M  0 part /boot
    ├─sda2                 8:2    0     1K  0 part 
    └─sda5                 8:5    0 465.5G  0 part 
      ├─bak10--vg-root   254:0    0 465.5G  0 lvm  /
      └─bak10--vg-swap_1 254:1    0     4G  0 lvm  [SWAP]
    sdb                    8:16   0 465.8G  0 disk
    

    Once you know the device you want to expand the LVM (Logical Volume Management) in this case ‘sdb’

    Take care to notice, there are many disk identifiers aka ‘sda’ depending on the specific distro you are using

    First you’ll want to install the required tools:

    sudo apt-get install system-config-lvm
    

    Then run:

    sudo vgdisplay
    

    In this case the LVM has already been expanded, either way, take note of the volume group, which you would have been prompted to define during the OS install.

    We can see here as the volume group as ‘VG Name’ bak10-vg

    Output:

    --- Volume group ---
      VG Name               bak10-vg
      System ID             
      Format                lvm2
      Metadata Areas        2
      Metadata Sequence No  5
      VG Access             read/write
      VG Status             resizable
      MAX LV                0
      Cur LV                2
      Open LV               2
      Max PV                0
      Cur PV                2
      Act PV                2
      VG Size               931.28 GiB
      PE Size               4.00 MiB
      Total PE              238407
      Alloc PE / Size       238407 / 931.28 GiB
      Free  PE / Size       0 / 0   
      VG UUID               I3z4RM-RAsq-HfPD-FiUo-KxOZ-Jpsg-zROJPt
    

    We also need the logical volume root path, this can be found by running:

    sudo lvdisplay
    

    We can see the volume group root path is ‘LV Path /dev/bak10-vg/root’ Output:

    --- Logical volume ---
    LV Path                /dev/bak10-vg/root
    LV Name                root
    VG Name                bak10-vg
    LV UUID                ykeSJi-Q1mw-dWui-5D7p-Lr1y-wk18-swWVN8
    LV Write Access        read/write
    LV Creation host, time bak10, 2016-12-24 10:43:48 -0500
    LV Status              available
    # open                 1
    LV Size                927.28 GiB
    Current LE             237383
    Segments               2
    Allocation             inherit
    Read ahead sectors     auto
    - currently set to     256
    Block device           254:0
     
    --- Logical volume ---
    LV Path                /dev/bak10-vg/swap_1
    LV Name                swap_1
    VG Name                bak10-vg
    LV UUID                URTRk2-lcke-7oq6-TAtK-EGg8-qyTf-pAmr9Z
    LV Write Access        read/write
    LV Creation host, time bak10, 2016-12-24 10:43:48 -0500
    LV Status              available
    # open                 2
    LV Size                4.00 GiB
    Current LE             1024
    Segments               1
    Allocation             inherit
    Read ahead sectors     auto
    - currently set to     256
    Block device           254:1
    

    Now we convert the disk ‘sdb’ into a physical volume by running:

    sudo pvcreate /dev/sdb
    

    Then we add the physical volume to the volume group by extending the existing volume group to the second disk:

    sudo vgextend bak10-vg /dev/sdb
    

    Then we allocate the physical volume to the logical volume. You can allocate a specific partition or percentage of the new disk, however this is basic by adding the complete disk:

    sudo lvextend -l +100%FREE /dev/bak10-vg/root
    

    Now we must resize the volume group to the new physical drive:

    sudo resize2fs /dev/bak10-vg/root
    

    The LVM has been expanded to the second disk ‘/dev/sdb’, where the first disk contains a default and basic partitioning scheme :

    lsblk
    
    NAME                 MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
    sda                    8:0    0 465.8G  0 disk 
    ├─sda1                 8:1    0   243M  0 part /boot
    ├─sda2                 8:2    0     1K  0 part 
    └─sda5                 8:5    0 465.5G  0 part 
      ├─bak10--vg-root   254:0    0 927.3G  0 lvm  /
      └─bak10--vg-swap_1 254:1    0     4G  0 lvm  [SWAP]
    sdb                    8:16   0 465.8G  0 disk 
    └─bak10--vg-root     254:0    0 927.3G  0 lvm  /
    

    None the less, we can see the two available physical disks ‘sda and sdb’ are now part of one file system.

    Where sda contains necessary basic partitions, and the second disk is now part of the volume group as usable space.

    Fin! Enjoy your new space!

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      lime-itL

      Again running smartctl after all is said and done:

      smartctl --all /dev/sda

      ddrescue-smartctl-after-rescue.png ddrescue-smartctl-2.png

      Yet an old drive in itself, I run the wheels off of them, and monitor regularly as anyone should.

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    • FSCK disk repair

      Linux Systems Guides
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      rickR

      FSCK(8) System Administration FSCK(8)

      NAME fsck - check and repair a Linux filesystem

      SYNOPSIS fsck [-lrsAVRTMNP] [-C [fd]] [-t fstype] [filesystem…] [–] [fs-specific-options]

      DESCRIPTION:

      fsck is used to check and optionally repair one or more Linux filesystems. filesys can be a device name (e.g. /dev/hdc1, /dev/sdb2), a mount point (e.g. /, /usr, /home), or an ext2 label or UUID specifier (e.g.UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd or LABEL=root).

      Normally, the fsck program will try to handle filesystems on different physical disk drives in parallel to reduce the total amount of time needed to check all of them.

      If no filesystems are specified on the command line, and the -A option is not specified, fsck will default to checking filesystems in /etc/fstab serially. This is equivalent to the -As options.

      The exit code returned by fsck is the sum of the following conditions: 0 No errors 1 Filesystem errors corrected 2 System should be rebooted 4 Filesystem errors left uncorrected 8 Operational error 16 Usage or syntax error 32 Checking canceled by user request 128 Shared-library error

      The exit code returned when multiple filesystems are checked is the bit-wise OR of the exit codes for each filesystem that is checked.

      In actuality, fsck is simply a front-end for the various filesystem checkers (fsck.fstype) available under Linux.

      The filesystem-specific checker is searched for in /sbin first, then in /etc/fs and /etc, and finally in the directories listed in the PATH environment variable. Please see the filesystem-specific checker manual pages for further details.

      OPTIONS:

      -l

      Lock the whole-disk device by an exclusive flock(2). This option can be used with one device only (this means that -A and -l are mutually exclusive). This option is recommended when more fsck(8) instances are executed in the same time.

      The option is ignored when used for multiple devices or for non-rotating disks.

      fsck does not lock underlying devices when executed to check stacked devices (e.g. MD or DM) – this feature is not implemented yet.

      -r

      Report certain statistics for each fsck when it completes. These statistics include the exit status, the maximum run set size (in kilobytes), the elapsed all-clock time and the user and system CPU time used by the fsck run.

      For example:

      /dev/sda1: status 0, rss 92828, real 4.002804, user 2.677592, sys 0.86186 -s

      Serialize fsck operations. This is a good idea if you are checking multiple filesystems and the checkers are in an interactive mode. (Note: e2fsck(8) runs in an interactive mode by default.

      To make e2fsck(8) run in a non-interactive mode, you must either specify the -p or -a option, if you wish for errors to be corrected automatically, or the -n option if you do not.)

      -t

      fslist

      Specifies the type(s) of filesystem to be checked. When the -A flag is specified, only filesystems that match fslist are checked. The fslist parameter is a comma-separated list of filesystems and options specifiers.

      All of the filesystems in this comma-separated list may be prefixed by a negation operator ‘no’ or ‘!’, which requests that only those filesystems not listed in fslist will be checked. If none of the filesystems in fslist is prefixed by a negation operator, then only those listed filesystems will be checked.

      Options specifiers may be included in the comma-separated fslist. They must have the format opts=fs-option. If an options specifier is present, then only filesystems which contain fs-option in their mount options field of /etc/fstab will be checked.

      If the options specifier is prefixed by a negation operator, then only those filesystems that do not have fs-option in their mount options field of /etc/fstab will be checked.

      For example, if opts=ro appears in fslist, then only filesystems listed in /etc/fstab with the ro option will be checked.

      For compatibility with Mandrake distributions whose boot scripts depend upon an unauthorized UI change to the fsck program, if a filesystem type of loop is found in fslist, it is treated as if opts=loop were specified as an argument to the -t option.

      Normally, the filesystem type is deduced by searching for filesys in the /etc/fstab file and using the corresponding entry.

      If the type can not be deduced, and there is only a single filesystem given as an argument to the -t option, fsck will use the specified filesystem type. If this type is not available, then the default filesystem type (currently ext2) is used.

      -A

      Walk through the /etc/fstab file and try to check all filesystems in one run. This option is typically used from the /etc/rc system initialization file, instead of multiple commands for checking a single filesystem.

      The root filesystem will be checked first unless the -P option is specified (see below). After that, filesystems will be checked in the order specified by the fs_passno (the sixth) field in the /etc/fstab file.

      Filesystems with a fs_passno value of 0 are skipped and are not checked at all. Filesystems with a fs_passno value of greater than zero will be checked in order, with filesystems with the lowest fs_passno number being checked first.

      If there are multiple filesystems with the same pass number, fsck will attempt to check them in parallel, although it will avoid running multiple filesystem checks on the same physical disk.

      fsck does not check stacked devices (RAIDs, dm-crypt, …) in parallel with any other device. See below for FSCK_FORCE_ALL_PARALLEL setting. The /sys filesystem is used to determine dependencies between devices.

      Hence, a very common configuration in /etc/fstab files is to set the root filesystem to have a fs_passno value of 1 and to set all other filesystems to have a fs_passno value of 2. This will allow fsck to automatically run filesystem checkers in parallel if it is advantageous to do so.

      System administrators might choose not to use this configuration if they need to avoid multiple filesystem checks running in parallel for some reason — for example, if the machine in question is short on memory so that excessive paging is a concern.

      fsck normally does not check whether the device actually exists before calling a filesystem specific checker. Therefore non-existing devices may cause the system to enter filesystem repair mode during boot if the filesystem specific checker returns a fatal error.

      The /etc/fstab mount option nofail may be used to have fsck skip non-existing devices.

      fsck also skips non-existing devices that have the special filesystem type auto.

      -C [fd]

      Display completion/progress bars for those filesystem checkers (currently only for ext2 and ext3) which support them. fsck will manage the filesystem checkers so that only one of them will display a progress bar at a time.

      GUI front-ends may specify a file descriptor fd, in which case the progress bar information will be sent to that file descriptor.

      -M

      Do not check mounted filesystems and return an exit code of 0 for mounted filesystems.

      -N

      Don’t execute, just show what would be done.

      -P

      When the -A flag is set, check the root filesystem in parallel with the other filesystems.

      This is not the safest thing in the world to do, since if the root filesystem is in doubt things like the e2fsck(8) executable might be corrupted!

      This option is mainly provided for those sysadmins who don’t want to re partition the root filesystem to be small and compact (which is really the right solution).

      -R

      When checking all filesystems with the -A flag, skip the root filesystem. (This is useful in case the root filesystem has already been mounted read-write.)

      -T

      Don’t show the title on startup.

      -V

      Produce verbose output, including all filesystem-specific commands that are executed.

      fs-specific-options

      Options which are not understood by fsck are passed to the filesystem-specific checker. These options must not take arguments, as there is no way for fsck to be able to properly guess which options take arguments and which don’t.

      Options and arguments which follow the – are treated as filesystem-specific options to be passed to the filesystem-specific checker.

      Please note that fsck is not designed to pass arbitrarily complicated options to filesystem-specific checkers.

      If you’re doing something complicated, please just execute the filesystem-specific checker directly. If you pass fsck some horribly complicated options and arguments, and it doesn’t do what you expect, don’t bother reporting it as a bug. You’re almost certainly doing something that you shouldn’t be doing with fsck

      Options to different filesystem-specific fsck’s are not standardized. If in doubt, please consult the man pages of the filesystem-specific checker.

      Although not guaranteed, the following options are supported by most filesystem checkers:

      -a

      Automatically repair the filesystem without any questions (use this option with caution). Note that e2fsck(8) supports -a for backward compatibility only.

      This option is mapped to e2fsck’s -p option which is safe to use, unlike the -a option that some filesystem checkers support.

      -n

      For some filesystem-specific checkers, the -n option will cause the fs-specific fsck to avoid attempting to repair any problems, but simply report such problems to stdout.

      This is however not true for all filesystem-specific checkers. In particular, fsck.reiserfs(8) will not report any corruption if given this option.fsck.minix(8) does not support the -n option at all.

      -r

      Interactively repair the filesystem (ask for confirmations). Note: It is generally a bad idea to use this option if multiple fsck’s are being run in parallel. Also note that this is e2fsck’s default behavior; it supports this option for backward compatibility reasons only.

      -y

      For some filesystem-specific checkers, the -y option will cause the fs-specific fsck to always attempt to fix any detected filesystem corruption automatically.

      Sometimes an expert may be able to do better driving the fsck manually. Note that not all filesystem-specific checkers implement this option. In particular fsck.minix(8) and fsck.cramfs(8) do not support the -y option as of this writing.

      FILES /etc/fstab.

      ENVIRONMENT VARIABLES

      The fsck program’s behavior is affected by the following environment variables:

      FSCK_FORCE_ALL_PARALLEL

      If this environment variable is set, fsck will attempt to check all of the specified filesystems in parallel, regardless of whether the filesystems appear to be on the same device. (This is useful for RAID systems or high-end storage systems such as those sold by companies such as IBM or EMC.) Note that the fs_passno value is still used.

      FSCK_MAX_INST

      This environment variable will limit the maximum number of filesystem checkers that can be running at one time. This allows configurations which have a large number of disks to avoid fsck starting too many filesystem checkers at once, which might overload CPU and memory resources available on the system.

      If this value is zero, then an unlimited number of processes can be spawned. This is currently the default, but future versions of fsck may attempt to automatically determine how many filesystem checks can be run based on gathering accounting data from the operating system.

      PATH

      The PATH environment variable is used to find filesystem checkers. A set of system directories are searched first: /sbin, /sbin/fs.d, /sbin/fs, /etc/fs, and /etc. Then the set of directories found in the PATH environment are searched.

      FSTAB_FILE

      This environment variable allows the system administrator to override the standard location of the /etc/fstab file. It is also useful for developers who are testing fsck.

      LIBBLKID_DEBUG=0xffff

      enables debug output.

      LIBMOUNT_DEBUG=0xffff

      enables debug output.

      SEE ALSO

      fstab(5), mkfs(8), fsck.ext2(8) or fsck.ext3(8) or e2fsck(8), cramfsck(8), fsck.minix(8), fsck.msdos(8), fsck.jfs(8), fsck.nfs(8), fsck.vfat(8), fsck.xfs(8), fsck.xiafs(8), reiserfsck(8).

      AUTHOR: Theodore Ts’o

      AVAILABILITY The fsck command is part of the util-linux package and is available from Linux Kernel Archive ftp://ftp.kernel.org/pub/linux/utils/util-linux/.

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FreeBSD Notes
  • rickR

    Screen recording can use webm as their format, it can be more simple to use a gif to embed into a website or forum, than adding scripts to host different video format.

    In this case I grabbed a screen record of the progress for writing zeros to a hard drive with dd

    Use ffmpeg to convert webm to gif:

    First create a pallet:

    Move into the directory which the webm is located, or type in the path

    Where ‘dd.webm’ is the screen recording

    ffmpeg -y -i dd.webm -vf palettegen palette.png

    Output:

    dd-ffmpeg.png

    Then convert the webm to gif:

    ffmpeg -y -i dd.webm -i palette.png -filter_complex paletteuse -r 10 dd.gif

    dd-webm-2.png

    This is what I ended up with, looks like any image of any alien on the interwebz, as if shot through a potato, some tweaking of the command is in my future. None the less.

    dd.gif

    read more

  • rickR

    Write zeros to all sectors

    Use the command ‘lsblk’ to find the drive you wish to erase

    I’m using ‘dd’ to erase things

    In this case I’m torching sdb

    Only use status=progress if you care it’s not necessary

    dd if=/dev/zero of=/dev/sdb bs=12M status=progress

    dd.gif

    read more

  • rickR

    Remove old kernel images that are cluttering the system

    zstd-no-space-error.png

    Most of these errors are due to low or not enough space left in the root partition.

    If you are using a Debian flavor:

    sudo apt-get autoremove --purge

    zstd-error.png

    Inform grub whenever an old kernel is removed:

    update grub

    update-grub.png

    Remove the un-used kernel config files:

    These will be the files pre cursed as ‘rc’ where installed kernels use ‘ii’

    … As well as files no longer used or required due to dependencies

    This command will detect, print, and remove left over cruft from previously installed packages or scripts, that have been removed or updated.

    sudo dpkg --purge $(dpkg -l | awk '/^rc/{print $2}')

    purge.png

    You can re-run the following to view the installed kernel(s):

    dpkg --list | grep linux-image

    installed-kernels.png

    read more

  • rickR

    To list all files in current directory including dot files (hidden files or directories), as well as print permissions :

    ls -la
    read more

  • rickR
    Install Ruby on Debian

    Install rbenv

    sudo apt install rbenv

    Then initialize the environment:

    rbenv init

    rbenv-init.png

    nano ~/.bashrc

    Type or paste the output above, Ctrl +x to save

    Apply:

    source .bashrc

    Install ruby-build

    Install git:

    sudo apt install git

    install-git.png

    mkdir -p "$(rbenv root)"/plugins

    Clone to local:

    git clone https://github.com/rbenv/ruby-build.git "$(rbenv root)"/plugins/ruby-build

    clone-ruby.png

    curl -fsSL https://github.com/rbenv/rbenv-installer/raw/main/bin/rbenv-doctor | bash

    ruby-doctor.png

    Now install Ruby:

    print ruby versions available

    rbenv install --list

    rb-list.png

    Install the latest version unless you have a reason otherwise:

    rbenv install 3.3.0

    On this system there was an error compiling at this point with fiddle, as well as psych: ruby-failed.png

    Therefore manually installing the following filled dependencies

    sudo apt install libtool sudo apt install libffi-dev

    rb-compile.png

    rbenv global 3.3.0

    print installed ruby version

    ruby -v

    ruby-version-installed.png

    read more