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Filesystem.md

File metadata and controls

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related
cheat-sheet
DRBD
LVM
Partitioning

Misc

  • detox: Tool for recursive cleanup of file names.

    detox -v -r <directory>

  • Fast File Deletion:

    perl -e 'for(<*>){((stat)[9]<(unlink))}'

  • POSIX ACLs:

    getfacl <file>                 # List ACLs for file 
setfacl -m user:joe:rwx dir    # Modify ACL
ls -ld <file>                  # Check for active ACL (indicates a "+")

  • uNetBootin: Create bootable media for any distribution. Most useful with USB sticks.

  • rsync - --delete doesn't work: It happens when you call rsync without a trailing slash in the source path like this:

    rsync -az -e ssh --delete /data server:/data

    It just won't delete anything. It will when running it like this:

    rsync -az -e ssh --delete /data/ server:/data

  • List physical disk serial number

      # As root
  hdparm -I /dev/sda | grep Serial
  lshw -class disk
  smartctl -i /dev/sda
  lsblk --nodeps -o name,serial

  # As user
  /sbin/udevadm info --query=property --name=sda |grep SERIAL

  • Debug drive events

      udevadm monitor            # Track any changes
  
  udevadm test /devices/pci0000:00/<id>

  • inotify - Detect file access

      apt-get install inotify-tools
  
  inotifywait -m -r /var/log           # Show all activity in all subdirs
  inotifywait -m -e create -r /data    # Show all file/dir creations
  inotifywait -m -e isdir -r /data     # Show all subdir accesses (e.g. before mkdir)
  
  inotifywait -m /var/log/auth.log     # Show all access to single file

  • losetup

    losetup /dev/loop0 <disk image>      # Create
losetup -e /dev/loop0 <disk image>   # Create with encryption
losetup /dev/loop0          # Get info on loop0
losetup -d /dev/loop0           # Detach
losetup -a              # List used loop devices

  • dm-crypt with/without LUKS

Automated Sync

Synching without a distributed filesystem

  • lsyncd: inotify based rsync daemon

    lsyncd -rsync /home remotehost.org::share/

    Or in foreground

    lsyncd -nodaemon -log all -rsyncssh <local dir> <remote host> <remote dir>

Distributed Filesystems

Name Vendor Distinguishing Features
HDFS Hadoop FUSE, NFS, HFTP, S3
Ceph Redhat NFS, POSIX, S3, Swift, Fuse, Docker support
GlusterFS Redhat NFS, POSIX, S3, Docker support, also as "Redhat Storage Server"
OCFS2 Oracle POSIX, often used with DRBD Block replication
Lustre Oracle POSIX, abandoned, used in HPC
MooseFS Core Technology POSIX, NFS drop-in

Cloud/SaaS

Name Vendor Distinguishing Features
Elastifile ECFS Google Cloud, AWS, Azure
Nooba Redhat End-user easy cluster on any cloud storage
Azure Netapp Files Azure, Google Cloud

SSD Erase

hdparm --user-master u --security-set-pass ctmagazin /dev/sdX
hdparm --user-master u --security-erase ctmagazin /dev/sdX