ZFS the beginning

How i created my first pool

Raidz2 has two redundant drives (aka raid6). on spare drive and autoreplace on so the spare drive is used automatic in case of drive failure.

zpool create zfs-pool-1 raidz2 /dev/disk/by-id/ata-TOSHIBA_HDWN180_67PQK0NNFP9E /dev/disk/by-id/ata-TOSHIBA_HDWN180_67PQK0NGFP9E /dev/disk/by-id/ata-TOSHIBA_HDWN180_67PSK0YAFP9E /dev/disk/by-id/ata-TOSHIBA_HDWN180_67PUK0KWFP9E /dev/disk/by-id/ata-TOSHIBA_HDWN180_67PUK0KUFP9E /dev/disk/by-id/ata-ST8000VN0022-2EL112_ZA16NRDD /dev/disk/by-id/ata-ST8000VN0022-2EL112_ZA16NR57 /dev/disk/by-id/ata-ST8000VN0022-2EL112_ZA16KL2F /dev/disk/by-id/ata-ST8000VN0022-2EL112_ZA16PGEQ /dev/disk/by-id/ata-ST8000VN0022-2EL112_ZA16PH49
zpool add zfs-pool-1 spare /dev/disk/by-id/ata-ST8000VN0022-2EL112_ZA15N257
zpool set autoreplace=on zfs-pool-1

Scrub

Make sure there there is a cronscript running scrub once a month on your data. you can initiate a scrub from commandline and see status from the status command

zpool scrub zfs-pool-1
zpool status zfs-pool-1

other commands

This is how you se alla parameters for you pool and the history for all zfs/zpool commands of your pool.

zpool get all zfs-pool-1
zpool set autoreplace=on zfs-pool-1
zpool history zfs-pool-1

Add Cache

Only read cache so an cheap ssd could be used,

With cache devices you would actually look at read optimized SSDs, and no real need for mirroring, because all data and metadata could be discarded at any moment without any risk to the rest of the pool.

zpool add mypool cache /dev/sdc

Designating Hot Spares

Devices can be designated as hot spares in the following ways:

  • When the pool is created with the zpool create command
    zpool create trinity mirror c1t1d0 c2t1d0 spare c1t2d0 c2t2d0
  • After the pool is created with the zpool add command
    zpool add mypool spare  /dev/sdc  /dev/sdd

Replacing Devices in a Storage Pool

After you have determined that a device can be replaced, use the zpool replace command to replace the device. If you are replacing the damaged device with different device, use syntax similar to the following:

zpool replace mypool /dev/sda /dev/sdb

This command migrates data to the new device from the damaged device or from other devices in the pool if it is in a redundant configuration. When the command is finished, it detaches the damaged device from the configuration, at which point the device can be removed from the system. If you have already removed the device and replaced it with a new device in the same location, use the single device form of the command. For example:

zpool replace mypool /dev/sda

This command takes an unformatted disk, formats it appropriately, and then resilvers data from the rest of the configuration.

My first dataset

dataset can not be created for already existing directories.

zfs create zfs-pool-1/samuel

make snapshot directory vissible

there is a secret .zfs directory in your dataset folder containing your snapshots.

zfs set snapdir=visible zfs-pool-1/samuel
zfs set snapdir=hidden zfs-pool-1

To list datasets (and zpools)

zfs list

Take a snapshot

mysnapshot can be anything you want.

zfs snapshot zfs-pool-1/samuel@mysnapshot

view all your snapshots

cd .zfs/snapshot

Renaming

zfs rename zfs-pool-1/samuel@now zfs-pool-1/samuel@testing

List all snapshots

zfs list -t snapshot -r zfs-pool-1/samuel

restoring snapshot

zfs rollback zfs-pool-1/samuel@testing

Destroy snapshot

zfs destroy zfs-pool-1/samuel@testing

disable atime

access time should always be disabled.

zfs get all zfs-pool-1
zfs set atime=off zfs-pool-1

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