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  * **zfsreminders** 
  * **Jonathan Haack**
  * **Haack's Networking**
  * **webmaster@haacksnetworking.org**

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//zfsreminders//      

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Create a pool on a single drive and specify a mountpoint for it. Note: use id, not uuid.

  zpool create -m /mnt/Pool Pool -f /dev/disk/by-id/b592...
  
If you have more than one drive to begin with, you can make mirrors as follows:

  zpool create -m /mnt/Pool Pool -f mirror /dev/disy/by-id/2323... /dev/disy/by-id/3232...

If you accidentally used short names, then export and import to change it asap like this:

  zpool export vms 
  zpool import -d /dev/disk/by-id vms
  
If you messed up and picked a wrong name and/or mountpoint, adjust later as follows. To rename:

  zpool export [pool_name]
  zpool import [original_pool_name] [new_pool_name]
  
To change mountpoint:

  zfs set mountpoint=/myspecialfolder mypool
  
If you now have more than one drive, add another drive as a mirror as follows:

  zpool attach nameofpool /dev/disk/by-id/currentdisk /dev/disk/by-id/newdisk
  
To create an encrypted dataset you generate a key and then specify the location and name of the pool as follows:

  dd if=/dev/random of=/secure/area/example.key bs=1 count=32
  zfs create -o encryption=on -o keyformat=raw -o keylocation=file:///mnt/vault/example.key pool/dataset
  
After reboot, import (mount), the data set as follows:

  zfs load-key pool/dataset
  zfs mount pool/dataset
  
If you need to delete a dataset, do the following:

  zfs destroy -r pool/dataset
  
To create snapshots, here is a reasonable template:

  DATE=`date +"%Y%m%d-%H:%M:%S"`
  /usr/sbin/zfs snapshot -r pool/dataset@backup_$DATE
  
To delete all snapshots and start over:

  zfs list -H -o name -t snapshot | xargs -n1 zfs destroy
  
To add a zfs cache or slog hard drive to your pool, do the following:

  zpool add pool cache /dev/disk/by-id/3434...
  zpool add pool log /dev/disk/by-id/3434...

To view current snapshots, do the following:

  zfs list -r -t snapshot -o name,creation pool/dataset
  zfs list -r -t snapshot -o name,creation pool
  
To view pool space, including snapshots, do the following:

  zfs list -ro space
  
To replace a failed drive, power down the host, remove drive, reboot, get ''by-id'' of the new drive, and run ''zpool status -v'' for hard drive number of old drive, then do:

  sudo zpool replace pool <hard-drive-number> /dev/disk/by-id/</dev/disk/by-id/newdrive>
  sudo zpool replace pool 3347762980558930904 /dev/disk/by-id/ata-WDC_WD...

To check the health, statistics, and basic specs of your pool:

  zpool status -v
  zpool iostat -v
  zpool list -v
  
Also, to see whether cache volume is necessary, run and look at cache hit/miss ratio:

  arc_summary

Change location of the keys for your encrypted datasets:

  sudo zfs set keylocation=file:///keys/my.key mypool/mydataset
  
Send and receive entire pool to new pool

  zfs snapshot -r pool1@latestsnap
  zfs send -R pool1@latestsnap | zfs receive -F pool2
  
Arc information
  
  arcstat
  arc_summary -d | less
  nano /etc/modprobe.d/zfs.conf
  <# 8GB example - 8*(2^30) = below>
  <#options zfs zfs_arc_max=8589934592>
  <# Set Max ARC size => 2GB == 2147483648 Bytes>
  <options zfs zfs_arc_max=2147483648>
  <# Set Min ARC size => 1GB == 1073741824>
  <options zfs zfs_arc_min=1073741824>
  cat /sys/module/zfs/parameters/zfs_arc_min
  cat /sys/module/zfs/parameters/zfs_arc_max

More examples ... 

 --- //[[webmaster@haacksnetworking.org|oemb1905]] 2024/04/21 23:12//
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