> For the complete documentation index, see [llms.txt](https://imarslo.gitbook.io/handbook/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://imarslo.gitbook.io/handbook/basic/disk.md).

# disk

* [check status](#check-status)
* [mount](#mount)
  * [mount ios](#mount-ios)
  * [mount smb](#mount-smb)
  * [mount cifs](#mount-cifs)
  * [mount nfs](#mount-nfs)
  * [mount temporary ram](#mount-temporary-ram)
  * [remount](#remount)
  * [disconnect the mount](#disconnect-the-mount)
* [LVM](#lvm)
  * [check current status](#check-current-status)
  * [add new pv ( Physical Volume )](#add-new-pv--physical-volume-)
  * [moving home with lvm](#moving-home-with-lvm)
  * [extend lv](#extend-lv)
  * [remove LVM](#remove-lvm)
  * [example](#example)
* [others](#others)
  * [NFS](#nfs)
  * [squid](#squid)
* [performance](#performance)
  * [check NFS performance](#check-nfs-performance)
  * [`iostat`](#iostat)
  * [`sar`](#sar)
  * [hdparm](#hdparm)
  * [dd](#dd)
* [samba](#samba)
  * [setup](#setup)
  * [configure](#configure)
  * [firewall is necessary](#firewall-is-necessary)
  * [enable services](#enable-services)
  * [smbclient](#smbclient)

### check status

* `$ lsblk`
* `$ ncdu`
* `$ pvs`
* `$ lvs`
* `$ vgs`
* `$ pvscan`
* `$ lvscan`
* `$ pvdisplay`
* `$ vgdisplay`
* `$ lvdisplay`
* `$ fdisk -l`
* `$ sfdisk  -l -uM`
* `$ lshw -class disk`
* `$ hwinfo --block --short`
* `$ cat /proc/partitions`
* `$ sudo blkid`

### mount

#### [mount ios](https://www.tecmint.com/how-to-mount-and-unmount-an-iso-image-in-linux/)

```bash
$ [[ -z $(findmnt /mnt/tmp) ]] || umount -f /mnt/tmp
$ mkdir /mnt/tmp
$ mount -t iso9660 -o loop /vol/builds/os/linux/RHEL-6.6-20140926.0-Server-x86_64-dvd1.iso  /mnt/tmp/

# or: https://www.commandlinefu.com/commands/view/152/mount-a-.iso-file-in-unixlinux
$ mount /path/to/file.iso /mnt/tmp -o loop
```

* [create cd/dvd iso](https://www.commandlinefu.com/commands/view/1396/create-a-cddvd-iso-image-from-disk.)

  ```bash
  $ readom dev=/dev/scd0 f=/path/to/image.iso

  # https://www.commandlinefu.com/commands/view/12852/create-a-cddvd-iso-image-from-disk.
  $ dd bs=1M if=/dev/scd0 of=./filename.iso OR readom -v dev='D:' f='./filename.iso' speed=2 retries=8

  # https://www.commandlinefu.com/commands/view/12726/create-a-cddvd-iso-image-from-disk.
  $ cat /dev/cdrom > ~/img.iso

  # https://www.commandlinefu.com/commands/view/8564/create-a-cddvd-iso-image-from-disk.
  $ cp /dev/cdrom file.iso

  # or
  $ mkisofs -o /tmp/cd.iso /tmp/directory/
  ```
* [copy iso to local](https://www.commandlinefu.com/commands/view/3352/how-to-copy-cddvd-into-hard-disk-.iso)

  ```bash
  $ dd if=/dev/cdrom of=whatever.iso
  ```
* [rip cd/dvd to iso](https://www.commandlinefu.com/commands/view/10957/rip-a-cddvd-to-iso-format.)

  ```bash
  $ dd if=/dev/cdrom of=~/cdrom_image.iso
  ```

#### mount smb

> \[!NOTE] references:
>
> * [Mounting a Samba share](https://apple.stackexchange.com/a/444568/254265)
> * [如何在 macOS 中停用 SMB 1 或 NetBIOS](https://support.apple.com/zh-tw/HT211927)
> * [Performance issues with SMB 2 and 3 connections](http://www.centralit-helpdesk.co.uk/index.php?pg=kb.page\&id=240)
> * [Linux系统运维: Samba 应用](https://www.yaolong.net/article/linux-ops-samba/)
> * [How can I mount an SMB share from the command line?](https://apple.stackexchange.com/a/699/254265)
> * [How to escape password for smb mount](https://apple.stackexchange.com/a/329712/254265)
> * [URL Encoded Characters](https://www.degraeve.com/reference/urlencoding.php)

**macos**

> \[!NOTE|label:references:]
>
> * [Secure way to mount a password protected cifs share in mac](https://serverfault.com/a/368527/129815)
>
>   ```bash
>   $ sudo security add-internet-password -a "username_here" -D "Network Password" -r "smb " -l "cifs_share" -s "myserver.com" -p "cifs_share" -w "password_here"  -T "/System/Library/CoreServices/NetAuthAgent.app/Contents/MacOS/NetAuthAgent"
>   $ sudo security add-internet-password -a "username_here" -D "Network Password" -r "afp " -l "cifs_share" -s "myserver.com" -p "cifs_share" -w "password_here"  -T "/System/Library/CoreServices/NetAuthAgent.app/Contents/MacOS/NetAuthAgent"
>   ```
>
>   * [`~/Library/Preferences/nsmb.conf`](https://serverfault.com/a/367956/129815)
>
>     ```bash
>     $ cat ~/Library/Preferences/nsmb.conf
>     [myserver.com]
>     username=username_here
>     password=password_here
>     ```

* via GUI :
  * Go -> Connect toServer -> `smb://<domain.com>/secured`

    ![samba](/files/tcZ8NXHsEmuSHNbeKeb4)
* via cmd
  * [`mount`](https://apple.stackexchange.com/a/699/254265)

    ```bash
    $ mkdir -p /Volumes/mount
    $ sudo mkdir -p $(whoami):staff /Volumes/mount

    # mount
    $ mount -t smbfs //user1:<password>@<domain.com>/share /Volumes/mount
    $ mount -t smbfs -o -d=755,-f=755 //<domain.com>/<path> /Volumes/mount
    # or
    $ mount -o nodev,nosuid -t smbfs //user:${PASSWORD}@<domain.com>/share /Volumes/mount

    # mount_smbfs
    $ mount_smbfs //user1@<domain.com>/share /Volumes/mount
    Password for <domain.com>: <password>

    # umount
    $ umount /Volumes/mount
    # force umount
    $ diskutil unmountDisk force "${mount_point}"
    ```
  * [`open`](https://apple.stackexchange.com/a/171822/254265)

    ```bash
    $ open "smb://user1:<password>@<domain.com>/path"
    ```
  * `osascript`

    ```bash
    $ /usr/bin/osascript -e "try" -e "mount volume \"smb://guest@${host}\"" -e "end try"

    # or with function
    function mymount {
        osascript <<EOF
    mount volume "smb://user@fqdn1/volume1"
    mount volume "smb://user@fqdn2/volume2"
    EOF
    }
    ```
* check

  ```bash
  $ mount
  ...
  //user1@<domain.com>/secured on /Volumes/mount (smbfs, nodev, nosuid, mounted by user1)

  # get hostname
  #                        handle for both mount format:  //marslo@domain.com/share
  #                                                       //domain.com/share
  #                                                                   v
  #                                                       +----------------------+
  $ mount -t nfs,cifs,smbfs | awk '{print $1}' | sed -rn 's:^//([^@/]*@)?([^/]+).*:\2:p'
  domain.com
  domain.com
  $ mount -t nfs,cifs,smbfs | awk '{print $1}' | sed -rn 's:^//([^@/]*@)?([^/]+).*:\2:p' | paste -sd'|'
  ```

**linux**

```bash
$ smbclient --user=user1 -L //<domain.com>

# or
$ smbclient //<domain.com>/secured -U user1
```

#### mount cifs

> \[!NOTE|label:references:]
>
> * [How do I pass credential file to mount.cifs?](https://serverfault.com/a/367942/129815)
> * [mount.cifs(8) - Linux man page](https://linux.die.net/man/8/mount.cifs)
> * [How do I use a credential file for CIFS in /etc/fstab?](https://askubuntu.com/q/1119819/92979)
> * [Safer alternative to using .smbcredentials](https://askubuntu.com/questions/1262419/safer-alternative-to-using-smbcredentials)
> * [CIFS vs SAMBA, What are the differences](https://unix.stackexchange.com/a/34793/29178)
> * [How do you provide domain credentials to ansible's mount module?](https://stackoverflow.com/a/30037952/2940319)
> * [How to access mounted network drive on Windows Linux Subsystem?](https://superuser.com/a/1565523/112396)

* environment setup

  ```bash
  # centos
  $ yum install cifs-utils

  # ubuntu
  $ sudo apt-get install cifs-utils
  ```
* create credential file

  ```bash
  $ echo "username=user1" > ~/.cifscredentials
  $ echo "password=password1" >> ~/.cifscredentials
  $ chmod 600 ~/.cifscredentials
  ```
* mount

  ```bash
  $ [[ -d /mnt/mynfs ]] || mkdir -p /mnt/mynfs
  $ sudo mount -t cifs //domain.com/path/to/target /mnt/mynfs -o credentials=~/.cifscredentials
  ```
* NFS share info

  ```bash
  $ rpcinfo domain.com | egrep "service|nfs"
  1:   program version netid     address             service    owner
  8:    100003    3    udp       domain.com.8.1      nfs
  9:    100003    3    tcp       domain.com.8.1      nfs
  ```

#### mount nfs

{% hint style="info" %}

> references
>
> * [Network File System (NFS)](https://ubuntu.com/server/docs/network-file-system-nfs)
> * [How To Set Up an NFS Mount on Ubuntu 20.04](https://www.digitalocean.com/community/tutorials/how-to-set-up-an-nfs-mount-on-ubuntu-20-04)
> * sample:
>   * **nfs server**: `domain.com`
>   * **sub-folder**: `/path/to/target`
>   * **mount to local**: `/mnt/mynfs`
>     {% endhint %}

```bash
$ sudo mkdir -p /mnt/mynfs
$ sudo mount -t nfs domain.com:/path/to/target /mnt/mynfs [-vvv]

# or force using nfsversion 4
$ sudo mount -t nfs -o nfsvers=4 domain.com:/path/to/target /mnt/mynfs [-vvv]

# or with permission (rw) and version 3
$ sudo mount -o rw,vers=3 -t nfs domain.com:/path/to/target /mnt/mynfs -vvv
```

* [test if sub-folder exists in remote nfs server](https://www.tecmint.com/how-to-setup-nfs-server-in-linux/)

  ```bash
  $ showmount -e domain.com | grep '/path/to/target'
  ```
* environment setup

  ```bash
  # centos
  $ yum install nfs-utils nfs-utils-lib
  $ yum install portmap (not required with NFSv4)
  # ubuntu
  $ sudo apt-get install nfs-common

  # for nfs4
  $ sudo apt-get install nfs-utils nfs-utils-lib
  ```

**check mount**

```bash
$ cat /etc/mtab | grep /folder_name
/dev/sdb1 /folder_name ext4 rw,seclabel,relatime,stripe=64 0 0
```

[**Check if folder is a mounted remote filesystem**](https://unix.stackexchange.com/a/72224/29178)

```bash
$ df -P -T /folder_name
Filesystem     Type 1024-blocks     Used  Available Capacity Mounted on
/dev/sdb1      ext4  744******* 658***** 699*******       1% /folder_name
```

* `df`

  ```bash
  $ df /local_storage
  Filesystem      1K-blocks     Used  Available Use% Mounted on
  /dev/sdb1      744******* 658***** 699*******   1% /folder_name
  ```
* `/etc/fstab`

  > \[!NOTE|label:references:]
  >
  > * [iMarslo : character#column](https://github.com/marslo/ibook/blob/marslo/docs/cheatsheet/text-processing/text-processing.html#column)

  ```bash
  $ cat /etc/fstab
  $ sed 's/#.*//' /etc/fstab | column --table --table-columns SOURCE,TARGET,TYPE,OPTIONS,PASS,FREQ --table-right PASS,FREQ
  ```
* [`findmnt`](https://www.tecmint.com/find-mounted-file-systems-in-linux/)

  ```bash
  $ findmnt --fstab /local_storage
  TARGET         SOURCE    FSTYPE OPTIONS
  /local_storage /dev/sdb1 ext4   defaults
  ```

**check nfs mount points**

```bash
$ df -h -F nfs [ | column -t ]
$ mount | column -t | grep -E 'type.*nfs
$ findmnt /mnt/mynfs
```

**check mount version**

{% hint style="info" %}

* [`nfsstat -c` will show you the NFS version actually being used](https://unix.stackexchange.com/a/185831/29178)

* [`nfsstat -m` will show statistics on mounted NFS filesystems](https://unix.stackexchange.com/a/138999/29178)

* `grep nfs /proc/mounts` equals `nfsstat -m`
  {% endhint %}

* local

  ```bash
  $ rpcinfo -p localhost
    program vers proto   port  service
     100000    4   tcp    111  portmapper
     100000    3   tcp    111  portmapper
     100000    2   tcp    111  portmapper
     100000    4   udp    111  portmapper
     100000    3   udp    111  portmapper
     100000    2   udp    111  portmapper
     100024    1   udp  38978  status
     100024    1   tcp  36415  status
     100021    1   udp  51669  nlockmgr
     100021    3   udp  51669  nlockmgr
     100021    4   udp  51669  nlockmgr
     100021    1   tcp  42699  nlockmgr
     100021    3   tcp  42699  nlockmgr
     100021    4   tcp  42699  nlockmgr
  ```

* [remote](https://unix.stackexchange.com/a/205736/29178)

  ```bash
  $ rpcinfo domain.com | egrep "service|nfs"
     program version netid     address             service    owner
      100003    3    udp       domain.com.8.1      nfs
      100003    3    tcp       domain.com.8.1      nfs
  ```

**setup nfs mount by default server boot**

```bash
$ sudo bash -c "cat > /etc/fstab" << EOF
domain.com:/path/to/target    /mnt/mynfs nfs defaults 0 0
EOF

# i.e.:
$ cat /etc/fstab | grep -v '^#' | column -t
/dev/mapper/cl-root                             /               xfs   defaults                    0  0
UUID=18c35fe1-36ad-4d7e-aeb6-88bdb6b145af       /boot           ext4  defaults                    1  2
UUID=6C3A-C81A                                  /boot/efi       vfat  umask=0077,shortname=winnt  0  2
/dev/mapper/cl-home                             /home           xfs   defaults                    0  0
/dev/mapper/cl-swap                             swap            swap  defaults                    0  0
domain.com:/path/to/target                      /path/to/mount  nfs   defaults                    0  0
```

**related configure**

* `/etc/fstab`
* `/etc/nsswitch.conf`
* `/etc/nfsmount.conf`
* `/etc/nfs.conf`
* `/proc/mounts`

#### [mount temporary ram](https://www.commandlinefu.com/commands/view/224/mount-a-temporary-ram-partition)

```bash
$ mount -t tmpfs tmpfs /mnt -o size=1024m
```

#### [remount](https://unix.stackexchange.com/a/280543/29178)

```bash
$ sudo mount -oremount,rw /

# or
$ sudo mount -oremount,ro /
```

* [remount nfs](https://www.commandlinefu.com/commands/view/5763/check-a-nfs-mountpoint-and-force-a-remount-if-it-does-not-reply-after-a-given-timeout.)

  ```bash
  $ NFSPATH=/mountpoint TIMEOUT=5; perl -e "alarm $TIMEOUT; exec @ARGV" "test -d $NFSPATH" || (umount -fl $NFSPATH; mount $NFSPATH)

  # remount if 5 secs no response
  $ NFSPATH=/mountpoint TIMEOUT=5;
  $ perl -e "alarm $TIMEOUT;
  $ exec @ARGV" "test -d $NFSPATH" || (umount -fl $NFSPATH; mount $NFSPATH) # TIMEOUT=5 SCRIPT_NAME=$(basename $0) for i in $@; do echo "Checking $i..." if ! perl -e "alarm $TIMEOUT; exec @ARGV" "test -d $i" > /dev/null 2>&1; then echo "$SCRIPT_NAME: $i is failing with retcode $?."1>&2 echo "$SCRIPT_NAME: Submmiting umount -fl $i" 1>&2 umount -fl $i; echo "$SCRIPT_NAME: Submmiting mount $i" 1>&2 mount $i; fi done
  ```

#### disconnect the mount

```bash
$ sudo umount /mnt/mynfs
```

* `device is busy`

  > \[!NOTE|label:references:]
  >
  > * [umount: device is busy. Why?](https://unix.stackexchange.com/a/35960/29178)

  ```bash
  # check who is occupy the device
  $ fuser -vm /path/to/mount
  $ sudo fuser -vm /jenkins
                       USER        PID ACCESS COMMAND
  /path/to/mount:      root     kernel mount /path/to/mount
                       devops    1369210 ..c.. bash
                       marslo    1377303 ..c.. bash

  # or
  $ lsof +f -- /path/to/mount
  # or interactively kill only processes with files open for writing
  $ sudo fuser -vmMkiv /path/to/mount
  # or force kill directly without asking
  $ sudo fuser -vmMk /path/to/mount

  # logout
  $ sudo pkill -KILL -u marslo
  $ sudo pkill -KILL -u devops

  # umount again
  $ sudo umount -f /path/to/mount
  ```

### LVM

> \[!NOTE|label:reference:]
>
> * [CONFIGURING AND MANAGING LOGICAL VOLUMES](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/configuring_and_managing_logical_volumes/index)
> * [CHAPTER 5. MODIFYING THE SIZE OF A LOGICAL VOLUME](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/configuring_and_managing_logical_volumes/assembly_modifying-logical-volume-size-configuring-and-managing-logical-volumes)
> * [LVM HOWTO](https://tldp.org/HOWTO/LVM-HOWTO/index.html)
> * [磁盘与分区: LVM](https://www.kancloud.cn/pshizhsysu/linux/1799734)
> * [\* Logical Volume Manager Administration](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/logical_volume_manager_administration/index)
> * [\* LVM in Linux — Create and Extend a Logical Volume](https://medium.com/@yhakimi/lvm-how-to-create-and-extend-a-logical-volume-in-linux-9744f27eacfe)

| COMMAND | NAME            |
| :-----: | --------------- |
|   `vg`  | Volume Group    |
|   `pv`  | Physical Volume |
|   `lv`  | Logical Volume  |

#### check current status

* lvm

  ```bash
  $ sudo vgs
    VG       #PV #LV #SN Attr   VSize    VFree
    vgubuntu   1   2   0 wz--n- <931.01g    0

  $ sudo lvs
    LV     VG       Attr          LSize    Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
    root   vgubuntu -wi-ao----    <929.10g
    swap_1 vgubuntu -wi-ao----    1.91g

  $ sudo pvs
    PV             VG       Fmt  Attr PSize    PFree
    /dev/nvme0n1p2 vgubuntu lvm2 a--  <931.01g      0
    /dev/sda3               lvm2 ---    <1.82t  <1.82t
  ```
* disk status

  ```bash
  $ sudo lsblk
  NAME                MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
  sda                   8:0    0   1.8T  0 disk
  ├─sda1                8:1    0   600M  0 part
  ├─sda2                8:2    0     1G  0 part /media/devops/99dad889-9bcc-4edb-baa9-3433c2502f18
  └─sda3                8:3    0   1.8T  0 part
  sdb                   8:16   1     0B  0 disk
  sr0                  11:0    1  1024M  0 rom
  nvme1n1             259:0    0 931.5G  0 disk
  ├─nvme1n1p1         259:2    0   512M  0 part
  └─nvme1n1p2         259:3    0   931G  0 part /media/devops/f99da1e7-9555-4cdc-9781-6dbc9e6153ca
  nvme0n1             259:1    0 931.5G  0 disk
  ├─nvme0n1p1         259:4    0   512M  0 part /boot/efi
  └─nvme0n1p2         259:5    0   931G  0 part
    ├─vgubuntu-root   253:0    0 929.1G  0 lvm  /var/snap/firefox/common/host-hunspell
    │                                           /
    └─vgubuntu-swap_1 253:1    0   1.9G  0 lvm  [SWAP]
  ```

#### add new pv ( Physical Volume )

```bash
$ sudo pvcreate /dev/nvme1n1p2
  Can't open /dev/nvme1n1p2 exclusively.  Mounted filesystem?
  Can't open /dev/nvme1n1p2 exclusively.  Mounted filesystem?

$ sudo mount | grep f99da1e7-9555-4cdc-9781-6dbc9e6153ca
/dev/nvme1n1p2 on /media/devops/f99da1e7-9555-4cdc-9781-6dbc9e6153ca type ext4 (rw,nosuid,nodev,relatime,errors=remount-ro,uhelper=udisks2)
$ sudo umount /dev/nvme1n1p2
$ sudo mount | grep f99da1e7-9555-4cdc-9781-6dbc9e6153ca

$ sudo lsblk /dev/nvme1n1
NAME                MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
nvme1n1             259:0    0 931.5G  0 disk
├─nvme1n1p1         259:2    0   512M  0 part
└─nvme1n1p2         259:3    0   931G  0 part

$ sudo pvcreate /dev/nvme1n1p2
WARNING: ext4 signature detected on /dev/nvme1n1p2 at offset 1080. Wipe it? [y/n]: y
  Wiping ext4 signature on /dev/nvme1n1p2.
  Physical volume "/dev/nvme1n1p2" successfully created.

$ sudo pvs
  PV             VG       Fmt  Attr PSize    PFree
  /dev/nvme0n1p2 vgubuntu lvm2 a--  <931.01g      0
  /dev/nvme1n1p2          lvm2 ---   931.01g 931.01g
  /dev/sda3               lvm2 ---    <1.82t  <1.82t
```

#### moving home with lvm

> \[!NOTE|label:references]
>
> * [Moving /home with LVM](https://askubuntu.com/a/923943/92979)

#### extend lv

```bash
# check status
$ sudo pvs
   PV         VG        Fmt  Attr PSize    PFree
    /dev/vda3  ubuntu-vg lvm2 a--   <38.00g     0
    /dev/vdb1  ubuntu-vg lvm2 a--  <275.00g     0
$ sudo vgs
    VG        #PV #LV #SN Attr   VSize    VFree
    ubuntu-vg   2   2   0 wz--n- <313.00g     0
$ sudo lvs
   LV             VG        Attr       LSize    Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
    ubuntu-lv      ubuntu-vg -wi-ao---- <100.00g
    ubuntu-lv-home ubuntu-vg -wi-ao----  100.00g
    ubuntu-lv-var  ubuntu-vg -wi-ao----  100.00g
$ sudo dmidecode -t1
$ sudo blkid
$ lsblk

# enable qemu-guest-agent
$ sudo apt-get install qemu-guest-agent
$ sudo systemctl restart qemu-guest-agent.service
$ sudo systemctl enable qemu-guest-agent.service
$ sudo systemctl status qemu-guest-agent.service

# create pv
$ sudo pvcreate /dev/temp

# extend vg
$ sudo vgextend ubuntu-vg /dev/temp

# extend lv
$ sudo lvextend -L +100G /dev/ubuntu-vg/ubuntu-lv-home
$ sudo resize2fs /dev/ubuntu-vg/ubuntu-lv-home
```

#### remove LVM

> \[!TIP]
>
> * remove order:
>   1. lv
>   2. pv
>   3. vg
> * [15.2.2. Removing an LVM2 Logical Volume for Swap](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/storage_administration_guide/swap-removing-lvm2)
> * [5.3.10. Removing Volume Groups](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/logical_volume_manager_administration/vg_remove)
> * [Linux Quick Tip: How to Delete or Remove LVM volumes](https://faun.pub/linux-quick-tip-how-to-delete-or-remove-lvm-volumes-7df4447102af)
> * [Removing an existing LVM volume](https://subscription.packtpub.com/book/cloud-and-networking/9781783288885/5/ch05lvl1sec45/removing-an-existing-lvm-volume)

```bash
$ sudo lvremove /dev/cl/home
# for swap
$ sudo swapoff -v /dev/cl/swap
$ sudo lvremove /dev/cl/swap
# and remove swap from `/etc/fstab`
$ sudo awk '!/\/dev\/cl\/swap/' /etc/fstab

$ sudo pvremove <pv-name>
$ sudo vgremove <vg-name>
```

#### example

* extends the logical volume /dev/myvg/homevol to 12 gigabytes

  ```bash
  $ sudo lvextend -L12G /dev/myvg/homevol
  lvextend -- extending logical volume "/dev/myvg/homevol" to 12 GB
  lvextend -- doing automatic backup of volume group "myvg"
  lvextend -- logical volume "/dev/myvg/homevol" successfully extended
  ```
* adds another gigabyte to the logical volume /dev/myvg/homevol

  ```bash
  $ sudo lvextend -L+1G /dev/myvg/homevol
  lvextend -- extending logical volume "/dev/myvg/homevol" to 13 GB
  lvextend -- doing automatic backup of volume group "myvg"
  lvextend -- logical volume "/dev/myvg/homevol" successfully extended
  ```

### others

#### NFS

{% hint style="info" %}

> references:
>
> * [\* NFS](https://www.kancloud.cn/pshizhsysu/linux/1799758)
>   {% endhint %}

#### squid

{% hint style="info" %}

> references:
>
> * [\* squid](https://www.kancloud.cn/pshizhsysu/linux/1799760)
>   {% endhint %}

### performance

#### check NFS performance

{% hint style="info" %}

> references:
>
> * [Using nfsstat and nfsiostat to troubleshoot NFS performance issues on Linux](https://www.redhat.com/sysadmin/using-nfsstat-nfsiostat)
> * [NFS poor write performance](https://serverfault.com/questions/682000/nfs-poor-write-performance)
> * [Analyzing Linux NFS server performance](https://serverfault.com/questions/38756/analyzing-linux-nfs-server-performance)
>   {% endhint %}

* `nfsstat`
* `nfsiostat`
* [collectl](http://collectl.sourceforge.net/)
  * `collectl -sjmf -oT`
  * `collectl -sn --verbose -oT`
  * `collectl -sJ -oTm`
* [`tshark -R nfs -i eth0`](https://serverfault.com/a/38893/129815)
* [`nfswatch`](http://nfswatch.sourceforge.net)
* `netstat -plaute | grep nfs`
* `watch -d "netstat -plaute | grep nfs | sort -k 4,5"`
* `iostat -mx <delay in sec.> <devices>`
* [`sudo fio --randrepeat=1 --ioengine=libaio --direct=0 --gtod_reduce=1 --name=test1 --filename=/media/ramdisk/test --bs=4k --iodepth=64 --size=4G --readwrite=randrw --rwmixread=75`](https://serverfault.com/a/938554/129815)
* [`time dd if=/dev/zero of=/mnt/nfs/testfile bs=16k count=128k`](https://serverfault.com/a/324489/129815)
* [`iozone -aRcU /mnt/nfs/ -f /mnt/nfs/testfile > logfile`](https://serverfault.com/a/324489/129815)

#### `iostat`

> \[!TIP|label:references:]
>
> * [show vmstat with timestamp](https://www.commandlinefu.com/commands/view/2682/vmstatiostat-with-timestamp)
>
>   ```bash
>   $ iostat <--params> | awk '{now=strftime("%Y-%m-%d %T "); print now $0}'
>   ```

```bash
$ iostat -x -d 1
Linux 3.10.0-957.27.2.el7.x86_64 (dc5-ssdfwtst3)  01/15/2021  _x86_64_  (4 CPU)

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s avgrq-sz avgqu-sz   await r_await w_await  svctm  %util
sda               0.00     0.09    0.07   13.91     6.83    81.26    12.61     0.01    0.93   11.40    0.88   0.38   0.53
dm-0              0.00     0.00    0.07   14.00     6.83    81.26    12.53     0.01    0.95   11.60    0.90   0.38   0.53
dm-1              0.00     0.00    0.00    0.00     0.00     0.00    52.91     0.00    0.64    0.64    0.00   0.48   0.00
```

#### `sar`

```bash
$ sar -bdp 1
Linux 3.10.0-957.27.2.el7.x86_64 (dc5-ssdfwtst3)  01/15/2021  _x86_64_  (4 CPU)

05:44:20 AM       tps      rtps      wtps   bread/s   bwrtn/s
05:44:21 AM    863.00    863.00      0.00  47048.00      0.00

05:44:20 AM       DEV       tps  rd_sec/s  wr_sec/s  avgrq-sz  avgqu-sz     await     svctm     %util
05:44:21 AM       sda    863.00  47048.00      0.00     54.52      2.86      3.33      0.16     14.20
05:44:21 AM centos-root    863.00  47048.00      0.00     54.52      2.88      3.33      0.16     14.20
05:44:21 AM centos-swap      0.00      0.00      0.00      0.00      0.00      0.00      0.00      0.00
```

#### hdparm

> \[!NOTE] hdparm - get/set SATA/IDE device parameters
>
> references:
>
> * [Linux and Unix Test Disk I/O Performance With dd Command](https://www.cyberciti.biz/faq/howto-linux-unix-test-disk-performance-with-dd-command/)
> * [hdparm Command Examples in Linux](https://www.thegeekdiary.com/hdparm-command-examples-in-linux/)
> * [hdparm command in Linux with Examples](https://www.geeksforgeeks.org/hdparm-command-in-linux-with-examples/)

```bash
$ sudo hdparm -Tt /dev/sda3
/dev/sda3:
 Timing cached reads:   15900 MB in  1.99 seconds = 7978.64 MB/sec
 Timing buffered disk reads: 1796 MB in  3.00 seconds = 598.17 MB/sec

$ sudo hdparm -Tt /dev/sda3
/dev/sda3:
 Timing cached reads:   18924 MB in  1.98 seconds = 9539.84 MB/sec
 Timing buffered disk reads: 102 MB in 12.88 seconds =   7.92 MB/sec
```

#### dd

> \[!NOTE|label:references:]
>
> * [Linux and Unix Test Disk I/O Performance With dd Command](https://www.cyberciti.biz/faq/howto-linux-unix-test-disk-performance-with-dd-command/)
> * [network speed without wasting disk](https://www.commandlinefu.com/commands/view/5799/test-network-speed-without-wasting-disk)

```bash
$ flush
$ echo 3 | sudo tee /proc/sys/vm/drop_caches
$ time dd if=/path/to/bigfile of=/dev/null bs=8k
```

* write speed

  ```bash
  $ dd if=/dev/zero of=/tmp/test1.img bs=1G count=1 oflag=dsync

  # for NFS ( 2Gb )
  $ time dd if=/dev/zero of=/mnt/nfs/testfile bs=16k count=128k
  ```
* read spead

  ```bash
  # for NFS ( 2Gb )
  $ time dd if=/mnt/nfs/testfile of=/dev/null bs=16k
  ```
* server latency time

  ```bash
  $ dd if=/dev/zero of=/tmp/test2.img bs=512 count=1000 oflag=dsync
  ```

### samba

> \[!NOTE] references:
>
> * [Instructions for setting up a secure Samba share on CentOS 8 Linux](https://support.cleo.com/hc/en-us/articles/360063139733-Instructions-for-setting-up-a-secure-Samba-share-on-CentOS-8-Linux)
> * [How to Install and Configure Samba on CentOS 8](https://www.linuxtechi.com/install-configure-samba-centos-8/)

#### setup

```bash
# install
$ sudo dnf install samba samba-common samba-client
$ sudo mv /etc/samba/smb.conf /etc/samba/smb.con.bak

# setup user
$ sudo groupadd secure_group
$ sudo useradd -g secure_group user1
$ sudo useradd -g secure_group user2

# create folder
$ sudo mkdir -p /srv/samba/shared
$ sudo mkdir -p /srv/samba/secure_shared

$ sudo smbpasswd -a user1
  password_1
$ sudo smbpasswd -a user2
  password_2
```

#### configure

```
$ cat /etc/samba/smb.conf
[global]
workgroup = WORKGROUP
server string = Samba Server %v
netbios name = centos-8
security = user
map to guest = bad user
dns proxy = no
ntlm auth = yes              // for windows
```

* for anonymous

  ```bash
  $ sudo chmod -R 0755 /srv/samba/shared
  $ sudo chown -R nobody:nobody /srv/samba/shared
  $ sudo chcon -t samba_share_t /srv/samba/shared
  # or
  $ sudo chcon -R system_u:object_r:samba_share_t:s0 /srv/samba/shared

  $ cat /etc/samba/smb.conf
  [anonymous]
  path = /srv/samba/shared
  browsable =yes
  writable = yes
  guest ok = yes
  read only = no
  force user = nobody

  $ testparm
  ```
* for secured

  ```
  $ sudo chmod -R 0770 /srv/samba/secure_shared
  $ sudo chcon -t samba_share -p /srv/samba/secure_shared
  $ sudo chown -R root:secure_group /srv/samba/secure_shared

  $ cat /etc/samba/smb.conf
  [secured]
  path = /srv/samba/secure_shared
  valid users = @secure_group
  guest ok = no
  writable = yes
  browsable = yes

  # verify the configuration is sound
  $ testparm
  ```

#### firewall is necessary

```bash
# centos
$ sudo firewall-cmd --add-service=samba --zone=public --permanent
$ sudo firewall-cmd --reload

# ubuntu: https://help.ubuntu.com/lts/serverguide/firewall.html
$ sudo ufw app list
$ sudo ufw allow Samba
$ sudo ufw allow from 192.168.0.0/24 to any app Samba
$ sudo ufw app info Samba
```

#### enable services

```
# enable service
$ sudo systemctl start smb
$ sudo systemctl enable smb
$ sudo systemctl status smb
$ sudo systemctl start nmb
$ sudo systemctl enable nmb
$ sudo systemctl status nmb
```

* config

  > \[!TIP] FILES :
  >
  > * /etc/nsmb.conf
  >   * The global configuration file.
  > * \~/Library/Preferences/nsmb.conf
  >   * The user's configuration file, conflicts will be overwritten by the global file.

  ```bash
  $ cat /etc/nsmb.conf
  [default]
  signing_required=no
  file_ids_off=yes
  ```

#### smbclient

```bash
$ smbclient -L //domain.com -U marslo -W domain.com
Password for [DOMAIN.COM\marslo]:

  Sharename       Type      Comment
  ---------       ----      -------
  ADMIN$          Disk      Remote Admin
  C$              Disk      Default share
  data            Disk
  IPC$            IPC       Remote IPC
  NETLOGON        Disk      Logon server share
  SYSVOL          Disk      Logon server share
SMB1 disabled -- no workgroup available
```

* if no permission

  ```bash
  $ smbclient -L //domain.com -U account -W domain.com
  Password for [DOMAIN.COM\account]:
  session setup failed: NT_STATUS_LOGON_FAILURE
  ```