quick question about ZFS disks in a pool?

[killmasta93]

Hi,
I was wondering if someone could explain to me about something different with raid 10 vs raid 1 in a zfs.
when i check the disks lsblk i see this

NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 931.5G  0 disk
|-sda1   8:1    0  1007K  0 part
|-sda2   8:2    0   512M  0 part
`-sda3   8:3    0   931G  0 part
sdb      8:16   0 931.5G  0 disk
|-sdb1   8:17   0  1007K  0 part
|-sdb2   8:18   0   512M  0 part
`-sdb3   8:19   0   931G  0 part
sdc      8:32   0 931.5G  0 disk
|-sdc1   8:33   0 931.5G  0 part
`-sdc9   8:41   0     8M  0 part
sdd      8:48   0 931.5G  0 disk
|-sdd1   8:49   0 931.5G  0 part
`-sdd9   8:57   0     8M  0 part

as for a raid 1 shows 3 partitions on both. but my question is how come sda and sdb are different from the others?
so if sdc gets damaged and i need to replace would i still need to install the grub? and just replicate from sdd

 

[Stoiko Ivanov]

Please post the output of `zpool status` - that usually shows a better picture of what is going on.

My guess is that sda and sdb are the first mirror of your raid 10 - and those contain a partition for efi and a bios-boot partition
the others have 2 disks because this is what zfs does with them if your provide a whole disk.

hope this helps!

 

[killmasta93]

Thanks for the reply, this is my zpool

root@prometheus4:~# zpool status -v
  pool: rpool
 state: ONLINE
  scan: scrub repaired 0B in 4h37m with 0 errors on Fri May 31 23:47:39 2019
config:

    NAME        STATE     READ WRITE CKSUM
    rpool       ONLINE       0     0     0
      mirror-0  ONLINE       0     0     0
        sda2    ONLINE       0     0     0
        sdb2    ONLINE       0     0     0
      mirror-1  ONLINE       0     0     0
        sdc     ONLINE       0     0     0
        sdd     ONLINE       0     0     0

errors: No known data errors

So lets say sdc disk dies out and i need to replace the disk i would follow the same procedure to replace the disk including install grub?

 

[Nemesiz]

OMG

sda2 - 512M
sdb2 - 512M

sdc - 931.5G
sdd - 931.5G

Is it really the pool size like this?

 

[Stoiko Ivanov]

How did you create the pool?
just checked setting up a RAID10 with zfs and the pve-5.4-1 iso - the first mirror-vdev contains 'sda3' and 'sdb3' (both being large partitions)