Zfs

1. read http://zfsonlinux.org/faq.html
2. read [ZFS%20Archlinux https://wiki.archlinux.org/index.php/ZFS]
3. install ZFS [Install%20ZFS http://zfsonlinux.org/epel.html]

yum install epel-release
yum localinstall --nogpgcheck http://archive.zfsonlinux.org/epel/zfs-release.el7.noarch.rpm
yum install kernel-devel zfs

systemctl enable dkms

rpm -qd zfs
man zpool
man zfs
man zfs-module-parameters

1. create zpool

ls -lh /dev/disk/by-id/

zpool create -n -o ashift=12 -O compression=lz4 -O atime=off -m /tank tank mirror ata-HGST_HUS724040ALA640_PN2331PBG32EMT-part4 ata-HGST_HUS724040ALA640_PN2334PBH1TR5R-part4
zfs create -b 4K -o primarycache=metadata -o com.sun:auto-snapshot=false -V 128G tank/swap
mkswap /dev/zvol/tank/swap

Add a line to /etc/fstab:

/dev/zvol/tank/swap none swap discard 0 0

swapon -a

1. add ZIL and L2ARC

parted -s /dev/sdc mklabel msdos parted -s /dev/sdd mklabel msdos

1. ZIL partititon, size: 8G

# c 2048 + (8 * 1024 * 1024 * 1024/512)-1
parted -s /dev/sdc -- mkpart primary 2048s 16779263s
parted -s /dev/sdd -- mkpart primary 2048s 16779263s

1. L2ARC partition, size: all rest

parted -s /dev/sdc -- mkpart primary 16779264s -1s
parted -s /dev/sdd -- mkpart primary 16779264s -1s

ls -lh /dev/disk/by-id/
zpool add tank log mirror ata-SAMSUNG_MZ7WD240HAFV-00003_S16LNYADA01822-part1 ata-SAMSUNG_MZ7WD240HAFV-00003_S16LNYADA01826-part1
zpool add tank cache ata-SAMSUNG_MZ7WD240HAFV-00003_S16LNYADA01822-part2 ata-SAMSUNG_MZ7WD240HAFV-00003_S16LNYADA01826-part2

zpool scrub tank
zpool status
arcstat.py
arc_summary.py | less

Показувати при zfs list dataset'и і snapshot'и

# zpool set listsnapshots=off tank

Подивития які є доступні features але не активні doc(ru)

# zpool upgrade 
This system supports ZFS pool feature flags.
All pools are formatted using feature flags.
Some supported features are not enabled on the following pools. Once a
feature is enabled the pool may become incompatible with software
that does not support the feature. See zpool-features(5) for details.
POOL  FEATURE
---------------
tank
     filesystem_limits
     large_blocks

# zpool upgrade -a активувати всі 
# zpool upgrade -v
This system supports ZFS pool feature flags.
The following features are supported:
FEAT DESCRIPTION
-------------------------------------------------------------
async_destroy                         (read-only compatible)
Destroy filesystems asynchronously.
empty_bpobj                           (read-only compatible)
Snapshots use less space.
lz4_compress
LZ4 compression algorithm support.
spacemap_histogram                    (read-only compatible)
Spacemaps maintain space histograms.
enabled_txg                           (read-only compatible)
Record txg at which a feature is enabled
hole_birth
Retain hole birth txg for more precise zfs send
extensible_dataset
Enhanced dataset functionality, used by other features.
embedded_data
Blocks which compress very well use even less space.
bookmarks                             (read-only compatible)
"zfs bookmark" command
filesystem_limits                     (read-only compatible)
Filesystem and snapshot limits.
large_blocks
Support for blocks larger than 128KB.

The following legacy versions are also supported:
VER  DESCRIPTION
---  --------------------------------------------------------
 1   Initial ZFS version
 2   Ditto blocks (replicated metadata)
 3   Hot spares and double parity RAID-Z
 4   zpool history
 5   Compression using the gzip algorithm
 6   bootfs pool property
 7   Separate intent log devices
 8   Delegated administration
 9   refquota and refreservation properties
 10  Cache devices
 11  Improved scrub performance
 12  Snapshot properties
 13  snapused property
 14  passthrough-x aclinherit
 15  user/group space accounting
 16  stmf property support
 17  Triple-parity RAID-Z
 18  Snapshot user holds
 19  Log device removal
 20  Compression using zle (zero-length encoding)
 21  Deduplication
 22  Received properties
 23  Slim ZIL
 24  System attributes
 25  Improved scrub stats
 26  Improved snapshot deletion performance
 27  Improved snapshot creation performance
 28  Multiple vdev replacements

For more information on a particular version, including supported releases,
see the ZFS Administration Guide.