File system Host OS Online grow Offline grow Online shrink Offline shrink
FAT32(X) misc. No 3rd-party No 3rd-party
NTFS Windows Yes Yes Yes Yes
ReFS Windows Yes ? No ?
Btrfs[51] Linux Yes No Yes No
ext4[52] Linux Yes Yes No Yes
HFS+ Linux No No No No
HFS+ macOS Yes No Yes No
APFS macOS ? ? ? ?
ZFS misc. Yes No No No
ReiserFS[59] Linux Yes Yes No Yes
XFS[60] Linux Yes No No No

Check info

lshw -short -C disk
lshw -class disk -class storage
lsblk -f # check file system type
tune2fs -l /dev/sda1 | grep -i count

gdisk -l /dev/sda  #fdisk many give wrong GPT partiton

# file -s /dev/vda
    /dev/vda: DOS/MBR boot sector
# file -s /dev/vda1
    /dev/vda1: Linux rev 1.0 ext4 filesystem data, UUID=... (needs journal recovery) (extents) (large files) (huge files)

Convert between MBR and GPT

sudo sgdisk -g /dev/sda
sudo sgdisk -m /dev/sda
sudo partprobe -s

mkpart, format

parted -s /dev/sdb mklabel gpt
parted -s /dev/sdb unit mib mkpart primary 0% 100% / 1MiB 512MiB

mkpart primary fat32 1MiB 512MiB
set 1 esp on

mkfs.ext4 /dev/sdb1


mount -o rw,remount /   # recovery

mount -o loop,ro $path $mount_point # ISO

mount.nfs $1:$2 $3
mount -tnfs4 -ominorversion=1 server_nfs_4.1:/dir\

echo $path $mount_point cifs username=$user,password=$passwd 0 0 >>  /etc/fstab # SMB


Loss NAS mount may cause hang!

cat /proc/mounts    # list mounted

/dev/vdb1               /root/data       ext4    defaults,noatime 0 0
/dev/cdrom              /media/CentOS           auto    user,noauto,exec,utf8        0    0
// /mnt/ISO/ cifs username=user,password=pwd 0 0
//servername/sharename /media/windowsshare cifs guest,uid=1000,iocharset=utf8 0 0
/dev/mapper/x--vg--root /home           btrfs   defaults,subvol=@home 0       2
/dev/sda2       /mymnt/win   ntfs-3g  rw,umask=0000,defaults 0 0

is checked by the dump(ext2/3 filesystem backup) utility. This field is usually set to 0, which disables the check. / sets the order for filesystem checks at boot time; see fsck(8). 1 for the root device, 2 for other partitions, 0 to disable checking. [Arch] If the root file system is btrfs, set to 0 instead of 1.


pvdisplay -v -m

            Wiping internal VG cache
            Wiping cache of LVM-capable devices
        --- Physical volume ---
        PV Name               /dev/sde1
        VG Name               wd500-vg
        PV Size               <422.53 GiB / not usable 0   
        Allocatable           yes 
        PE Size               4.00 MiB
        Total PE              108167
        Free PE               5523
        Allocated PE          102644
        PV UUID               nPoenO-vin9-wkZF-4Dxh-5WT2-yU3f-EtAMs5

        --- Physical Segments ---
        Physical extent 0 to 5522:
        Physical extent 5523 to 95122:
            Logical volume  /dev/wd500-vg/data
            Logical extents 0 to 89599
        Physical extent 95123 to 95366:
            Logical volume  /dev/wd500-vg/swap_1
            Logical extents 0 to 243
        Physical extent 95367 to 108166:
            Logical volume  /dev/wd500-vg/data
            Logical extents 89600 to 102399

create vg+lv & format & mount:

vgcreate vg-name /dev/sdc3
lvcreate -L 80G wd500-vg -n data
mkfs.btrfs /dev/mapper/wd500--vg-data
mount /dev/mapper/wd500--vg-data /data2
echo $(cat /proc/mounts | tail -n 1) >> /etc/fstab ; ls /etc/fstab ;

vg operations

vgrename $vg_uuid new-vg-name

vgchange -ay # Activate vg

Add disk to vg

pvcreate /dev/sdb   # delete all partitions first
vgextend ubuntu-vg /dev/sdb

Remove disk from vg:

pvmove /dev/sdb1
vgreduce myvg /dev/sdb1

lv operations

lvremove sandisk-u2/mint

Resize fs

PV thrink: gparted

lvresize -L +20G /dev/debian9-vg/root # -r, --resizefs
resize2fs /dev/dlvebian9-vg/root

yum install e4fsprogs
resize4fs /dev/debian9-vg/root # resize ext4 if resize2fs error: Filesystem has unsupported feature(s)

lvextend --resize-fs --extents +100%FREE vg/lv # not support btrfs


btrfs filesystem show /mnt/intel160
btrfs filesystem usage /

btrfs device usage  /mnt/intel160G  # get {device ID}
btrfs filesystem resize 7:max /mnt/point # {device ID}
btrfs filesystem resize +60G /data # use gparted for shrink

dmesg | grep crc32c # verify if Btrfs checksum is hardware accelerated, e.g.: crc32c-intel


btrfs subvolume delete snapshot1/ 
# mv snapshot folder will be very slow

btrfs subvolume snapshot /var/lib/docker /var/lib/docker/btrfs/snapshot_20201230

btrfs subvolume list /var/lib/docker

mount -o subvolid=298 /dev/sda5 /var/lib/docker




swapoff -v /dev/mapper/ubuntu--vg-swap_1
lvreduce --size -22G /dev/debian9-vg/swap
mkswap /dev/mapper/ubuntu--vg-swap_1
swapon -va

echo /dev/VG/LV swap swap defaults 0 0 >> /etc/fstab



    dd if=/dev/zero of=./test_iops bs=4k count=10000 oflag=direct
    dd if=/dev/zero of=./test_bw   bs=1G count=1     oflag=direct


git clone && cd fio/examples/

fio --name=randwrite --ioengine=libaio --group_reporting \
 --iodepth=1 --rw=randwrite \
 --direct=1 --bs=4k --numjobs=8 \
 --size=512M --runtime=5

fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=random_read.fio --bs=4k --iodepth=64 --size=4G --readwrite=randread
fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=random_write.fio --bs=4k --iodepth=64 --size=4G --readwrite=randwrite


apt install smartmontools

smartctl --info /dev/sdf

smartctl --test=short /dev/sdf

smartctl --all /dev/sdf

smartctl -l selftest /dev/sdf
smartctl -l xerror /dev/sdf
-l TYPE, --log=TYPE
        Show device log. TYPE: error, selftest, selective, directory[,g|s],
                            xerror[,N][,error], xselftest[,N][,selftest],
                            background, sasphy[,reset], sataphy[,reset],
                            scttemp[sts,hist], scttempint,N[,p],
                            scterc[,N,M], devstat[,N], ssd,
                            gplog,N[,RANGE], smartlog,N[,RANGE]



docker run  --restart=unless-stopped --net host --name samba  \ 
    -v /data:/data -d \
    dperson/samba -p -s "public;/data;yes;no"


apt install samba
vi /etc/samba/smb.conf

    comment = public anonymous access
    path = /data
    browsable =yes
    create mask = 0660
    directory mask = 0771
    writable = yes
    guest ok = yes

service smbd restarttart