Zfs

here is how to work with zfs.

Beginning ZFS instances

There are only two commmands to interact with ZFS.

zpool: used to create a ZFS vdev (virtual device).  vdevs are composed of physical devices.  
zfs: used to create/interact with a ZFS dataset.  ZFS datasets are akin to logical volumes

# zpool creation syntax
zpool create <poolname> <vdev(s)> 
# Create a zpool of six raidz2 vdevs, each with six drives.  Includes two SSDs to used as a mirrored SLOG and one SSD as an L2ARC read cache.  (example commmand was run on qof) 
zpool create ex9 raidz2 sda sdb sdc sdd sde sdf raidz2 sdg sdh sdi sdj sdk sdl raidz2 sdm sdn sdo sdp sdq sdr raidz2 sds sdt sdu sdv sdw sdx raidz2 sdy sdz sdaa sdab sdac sdad raidz2 sdae sdaf sdag sdah sdai sdaj log mirror ata-INTEL_SSDSC2KG480G7_BTYM740603E0480BGN ata-INTEL_SSDSC2KG480G7_BTYM7406019K480BGN cache ata-INTEL_SSDSC2KG480G7_BTYM740602GN480BGN
 [root@qof ~]# zpool status
 pool: ex9
 state: ONLINE
 scan: none requested
 config:
 NAME                                            STATE     READ WRITE CKSUM
 ex9                                             ONLINE       0     0     0
 raidz2-0                                      ONLINE       0     0     0
   sda                                         ONLINE       0     0     0
   sdb                                         ONLINE       0     0     0
   sdc                                         ONLINE       0     0     0
   sdd                                         ONLINE       0     0     0
   sde                                         ONLINE       0     0     0
   sdf                                         ONLINE       0     0     0
 raidz2-1                                      ONLINE       0     0     0
   sdg                                         ONLINE       0     0     0
   sdh                                         ONLINE       0     0     0
   sdi                                         ONLINE       0     0     0
   sdj                                         ONLINE       0     0     0
   sdk                                         ONLINE       0     0     0
   sdl                                         ONLINE       0     0     0
 raidz2-2                                      ONLINE       0     0     0
   sdm                                         ONLINE       0     0     0
   sdn                                         ONLINE       0     0     0
   sdo                                         ONLINE       0     0     0
   sdp                                         ONLINE       0     0     0
   sdq                                         ONLINE       0     0     0
   sdr                                         ONLINE       0     0     0
 raidz2-3                                      ONLINE       0     0     0
   sds                                         ONLINE       0     0     0
   sdt                                         ONLINE       0     0     0
   sdu                                         ONLINE       0     0     0
   sdv                                         ONLINE       0     0     0
   sdw                                         ONLINE       0     0     0
   sdx                                         ONLINE       0     0     0
 raidz2-4                                      ONLINE       0     0     0
   sdy                                         ONLINE       0     0     0
   sdz                                         ONLINE       0     0     0
   sdaa                                        ONLINE       0     0     0
   sdab                                        ONLINE       0     0     0
   sdac                                        ONLINE       0     0     0
   sdad                                        ONLINE       0     0     0
 raidz2-5                                      ONLINE       0     0     0
   sdae                                        ONLINE       0     0     0
   sdaf                                        ONLINE       0     0     0
   sdag                                        ONLINE       0     0     0
   sdah                                        ONLINE       0     0     0
   sdai                                        ONLINE       0     0     0
   sdaj                                        ONLINE       0     0     0
 logs
 mirror-6                                      ONLINE       0     0     0
   ata-INTEL_SSDSC2KG480G7_BTYM740603E0480BGN  ONLINE       0     0     0
   ata-INTEL_SSDSC2KG480G7_BTYM7406019K480BGN  ONLINE       0     0     0
 cache
 ata-INTEL_SSDSC2KG480G7_BTYM740602GN480BGN    ONLINE       0     0     0

situation

zpool status
zfs list
zfs get all

mount after reboot

zfs set mountpoint=/export/db2 db2 

when you put in a new disk

fdisk -l 

to see what is new

sudo zpool create -f /srv/db3 raidz2 /dev/sdaa  /dev/sdab  /dev/sdac  /dev/sdad  /dev/sdae  /dev/sdaf  /dev/sdag  /dev/sdah  /dev/sdai  /dev/sdaj  /dev/sdak  /dev/sdal  
sudo zpool add -f /srv/db3 raidz2  /dev/sdam  /dev/sdan  /dev/sdao  /dev/sdap  /dev/sdaq  /dev/sdar  /dev/sdas  /dev/sdat  /dev/sdau  /dev/sdav  /dev/sdaw  /dev/sdax

zfs unmount db3

zfs mount db3

latest

zpool create -f db3 raidz2  /dev/sdy /dev/sdz  /dev/sdaa  /dev/sdab  /dev/sdac  /dev/sdad  /dev/sdae  /dev/sdaf  /dev/sdag  /dev/sdah  /dev/sdai  /dev/sdaj
zpool add -f db3 raidz2 /dev/sdak  /dev/sdal  /dev/sdam  /dev/sdan  /dev/sdao  /dev/sdap  /dev/sdaq  /dev/sdar  /dev/sdas  /dev/sdat  /dev/sdau  /dev/sdav

zpool create -f db4 raidz2 /dev/sdax /dev/sday /dev/sdaz /dev/sdba  /dev/sdbb  /dev/sdbc  /dev/sdbd  /dev/sdbe  /dev/sdbf  /dev/sdbg  /dev/sdbh  /dev/sdbi 
zpool add -f db4 raidz2 /dev/sdbj /dev/sdbk /dev/sdbl /dev/sdbm /dev/sdbn /dev/sdbo /dev/sdbp /dev/sdbq /dev/sdbr /dev/sdbs /dev/sdbt /dev/sdbu

Fri Jan 19 2018

zpool create -f db5 raidz2 /dev/sdbw /dev/sdbx /dev/sdby /dev/sdbz /dev/sdca  /dev/sdcb  /dev/sdcc  /dev/sdcd  /dev/sdce  /dev/sdcf  /dev/sdcg  /dev/sdch
zpool add -f db5 raidz2 /dev/sdci /dev/sdcj /dev/sdck /dev/sdcl /dev/sdcm /dev/sdcn /dev/sdco /dev/sdcp /dev/sdcq /dev/sdcr /dev/sdcs /dev/sdct
zfs mount db5

Wed Jan 24 2018

On tsadi

zpool create -f ex1 mirror /dev/sdaa /dev/sdab /dev/sdac /dev/sdad /dev/sdae
zpool add -f ex1 mirror /dev/sdaf /dev/sdag /dev/sdah /dev/sdai /dev/sdaj
zpool create -f ex2 mirror /dev/sdf /dev/sdg /dev/sdh /dev/sdi /dev/sdj
zpool add -f ex2 /dev/sdk /dev/sdl /dev/sdm /dev/sdn /dev/sdo
zpool create -f ex3 mirror /dev/sdp /dev/sdq /dev/sdr /dev/sds /dev/sdt
zpool add -f ex3 mirror /dev/sdu /dev/sdv /dev/sdw /dev/sdx /dev/sdy
zpool create -f ex4 mirror /dev/sdz /dev/sdak /dev/sdal
zpool add -f ex4 mirror /dev/sdam /dev/sdan /dev/sdao

On tsadi

zpool create -f ex1 mirror /dev/sdaa /dev/sdab mirror /dev/sdac /dev/sdad mirror /dev/sdae /dev/sdaf mirror /dev/sdag /dev/sdah mirror  /dev/sdai /dev/sdaj
zpool create -f ex2 mirror  /dev/sdf /dev/sdg mirror /dev/sdh /dev/sdi mirror /dev/sdj /dev/sdk mirror /dev/sdl /dev/sdm mirror /dev/sdn /dev/sdo
zpool create -f ex3 mirror /dev/sdp /dev/sdq mirror /dev/sdr /dev/sds mirro /dev/sdt /dev/sdu mirror /dev/sdv /dev/sdw mirror /dev/sdx /dev/sdy
zpool create -f ex4 mirror /dev/sdz /dev/sdak /dev/sdal  mirror /dev/sdam mirror /dev/sdan /dev/sdao

On lamed

zpool create -f ex5 mirror /dev/sdaa /dev/sdab mirror /dev/sdac /dev/sdad mirror /dev/sdae /dev/sdaf mirror /dev/sdag /dev/sdah mirror  /dev/sdai /dev/sdaj
zpool create -f ex6 mirror  /dev/sda /dev/sdb mirror /dev/sdc /dev/sdd mirror /dev/sde /dev/sdf mirror /dev/sdg /dev/sdh mirror /dev/sdi /dev/sdj
zpool create -f ex7 mirror  /dev/sdk /dev/sdl mirror /dev/sdm /dev/sdn mirror /dev/sdo /dev/sdp mirror /dev/sdq /dev/sdr mirror /dev/sds /dev/sdt
zpool create -f ex8 mirror /dev/sdu /dev/sdv mirror /dev/sdw /dev/sdx mirror /dev/sdy /dev/sdz

zfs mount

recovery from accidental pool destruction

umount /mnt /mnt2
mdadm -S /dev/md125/dev/md126/dev/md127

sfdisk -d /dev/sda < sda.sfdisk
sfdisk -d /dev/sdb < sdb.sfdisk
sfdisk /dev/sda < sdb.sfdisk

mdadm --detail /dev/md127
mdadm -A -R /dev/md127/dev/sdb2/dev/sda2
mdadm /dev/md127 -a /dev/sda2
mdadm --detail /dev/md127
echo check > /sys/block/md127/md/sync_action
cat /proc/mdstat

mdadm --detail /dev/md126
mdadm -A -R /dev/md126/dev/sdb3/dev/sda3
mdadm /dev/md126 -a /dev/sda3
mdadm --detail /dev/md126
echo check > /sys/block/md126/md/sync_action
cat /proc/mdstat

Also switched the bios to boot from hd2 instead of hd1 (or something)

• Recreate zpool with correct drives
• Point an instance photorec at each of the wiped drives set to recover files of the following types: .gz, .solv (custom definition)

NOTE: If you destroyed your zpool with command 'zpool destroy', you can use the command 'zpool import' to view destroyed pools and recover the pool by doing 'zpool import <zpool name>'.