ZFS 4 1TB disk Raid 1 - 1TB total storage, not 2TB...

[windswept321]

I just set up a new Proxmox server, which will be more of a remote backup server. It has 4x 1TB drives in a ZFS raid 1 array. I expected around 2TB of storage from this, not 1TB. Do I have a misconfiguration, or am I wrong?


zpool status:

pool: rpool


 state: ONLINE


config:

        NAME                                          STATE     READ WRITE CKSUM


        rpool                                         ONLINE       0     0     0


          mirror-0                                    ONLINE       0     0     0


            ata-SAMSUNG_HD103SI_S1VSJ9CS401090-part3  ONLINE       0     0     0


            ata-SAMSUNG_HD103UJ_S13PJDWQ736759-part3  ONLINE       0     0     0


            ata-SAMSUNG_HD103UJ_61911B761A0709-part3  ONLINE       0     0     0


            ata-SAMSUNG_HD103SJ_S246J9FZA12098-part3  ONLINE       0     0     0

zpool list:

NAME    SIZE  ALLOC   FREE  CKPOINT  EXPANDSZ   FRAG    CAP  DEDUP    HEALTH  ALTROOT
rpool   928G  64.1G   864G        -         -     0%     6%  1.00x    ONLINE  -

fdisk -l

Disk /dev/sda: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: SAMSUNG HD103SI
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 603E2CAB-61F2-409A-A343-D678ADDA9AEE

Device       Start        End    Sectors  Size Type
/dev/sda1       34       2047       2014 1007K BIOS boot
/dev/sda2     2048    1050623    1048576  512M EFI System
/dev/sda3  1050624 1953525134 1952474511  931G Solaris /usr & Apple ZFS

Disk /dev/sdb: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: SAMSUNG HD103UJ
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: CC5E4CFF-7B3D-4C7E-977B-0ED61E8CE1D9

Device       Start        End    Sectors  Size Type
/dev/sdb1       34       2047       2014 1007K BIOS boot
/dev/sdb2     2048    1050623    1048576  512M EFI System
/dev/sdb3  1050624 1953525134 1952474511  931G Solaris /usr & Apple ZFS

Disk /dev/sdc: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: SAMSUNG HD103UJ
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: E9DD7B33-3BE2-4C96-BCDA-5D7EA7130AAA

Device       Start        End    Sectors  Size Type
/dev/sdc1       34       2047       2014 1007K BIOS boot
/dev/sdc2     2048    1050623    1048576  512M EFI System
/dev/sdc3  1050624 1953525134 1952474511  931G Solaris /usr & Apple ZFS

Disk /dev/sdd: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: SAMSUNG HD103SJ
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 75D10AC1-C92D-41EA-B78C-F27585C7C7EC

Device       Start        End    Sectors  Size Type
/dev/sdd1       34       2047       2014 1007K BIOS boot
/dev/sdd2     2048    1050623    1048576  512M EFI System
/dev/sdd3  1050624 1953525134 1952474511  931G Solaris /usr & Apple ZFS

 

[Neobin]

Currently you have a quad-mirror. What you probably want is a striped mirror aka raid10.

 

[windswept321]

Ok, that makes sense. It's a pretty old HP microserver which won't have much to do so 1TB is probably enough for backup purposes. Thanks for responding.

 

[Dunuin]

Quad-Mirror is overkill. Recreate it as a striped mirror (aka raid10) to get 2TB capacity or as raidz1 (like a raid5) for 3TB capacity. Or even as a raidz2 (like raid6) for 2TB capacity with additional reliability. Striped mirror would be best for performance, but when it is just for backups I would prefer a raidz1 or raidz2.

 

[windswept321]

Quad-Mirror is overkill. Recreate it as a striped mirror (aka raid10) to get 2TB capacity or as raidz1 (like a raid5) für 3TB capacity. Or even as a raidz2 (like raid6) for 2TB capacity with additional reliability. Striped mirror would be best for performance, but when it is just for backups I would prefer a raidz1 or raidz2.

Thanks for the advice, I appreciate it. Setting up again as raidz2...

 

[Dunuin]

Thanks for the advice, I appreciate it. Setting up again as raidz2...

Then make sure to increase the blocksize of the ZFS storage to at least 16K (or 64K even less padding loss) in case you also want to use zvols and not just datasets.

 

[windswept321]

and then I get a totally random drive communication failure on the first boot... it follows the drive so it must have gone bad. Time for a new one!