New install, four 3TB disks - no option for RAID-Z?

[victorhooi]

Hi,

I've installed a new instance of FreeNAS 9.2.1 (Beta).

I've added four 3 TB drives to the machine (yes, I know this is apparently sub-optimal for RAID-Z, and powers of two plus one are optimal?).

When I go to create a new ZFS volume I can't seem to see any option to create RAID-Z volumes?

Any thoughts on how I can do it?

Cheers,
Victor

 

[victorhooi]

Hi,

Aha, wait - I saw that I can do it via Manual setup =).

Question - how bad is it that I'm doing RAID-Z with four disks? What are the major tradeoffs?

This thread:

http://forums.freenas.org/threads/disk-management-advice-needed.10865/

seems to imply that there's a performance hit - but elsewhere I've read it only talks about poor space usage?

It's a four-bay NAS - what other configurations would you guys recommend, and what are the performance/space tradeoffs for those? I have 7.8 TB available capacity currently on RAIDZ - I'm guessing that if I go to RAIDZ2, that will decrease significantly - but my performance will go up?

Cheers,
Victor

 

[Dusan]

Drag the circle slider up & right to get one row of four drives instead of two rows of two drives.

 

[victorhooi]

Hi,

Hmm, so I created my RAID-Z array, and theres are my IO stats with zpool iostat:

Code:

                                          capacity    operations    bandwidth
pool                                    alloc  free  read  write  read  write
--------------------------------------  -----  -----  -----  -----  -----  -----
datastore                              7.69G  10.9T      0    131      0  12.9M
  raidz1                                7.69G  10.9T      0    131      0  12.9M
    gptid/36d5bb2e-86cf-11e3-8a5c-10604b92dc14      -      -      0    60      0  4.46M
    gptid/37e9e6af-86cf-11e3-8a5c-10604b92dc14      -      -      0    49      0  4.45M
    gptid/388b045d-86cf-11e3-8a5c-10604b92dc14      -      -      0    59      0  4.46M
    gptid/39059520-86cf-11e3-8a5c-10604b92dc14      -      -      0    59      0  4.46M
--------------------------------------  -----  -----  -----  -----  -----  -----

This is with four consumer-grade 7200rpm 3TB drives, and doing an RSync for large files (2-4 Gb each) over Gigabit Ethernet.

It's definitely a lot lower performance than I was seeing before when I had striping (which was only meant to be a temporary thing...lol, but I waited for my 3TB drives to arrive).

Does this sort of performance seem reasonable to you guys? Is it because of RAID-Z on four drives? Or do you think there might be something else going on here?

Cheers,
Victor

 

[Aberu]

https://calomel.org/zfs_raid_speed_capacity.html - This is using an almost best case scenario SATA controller. Are you using the one built-into your motherboard? If so, that still looks low to me, what SATA controller are you using?

What are the model of hard drive?

 

[danb35]

Holy necro-thread, Batman!

 

[pirateghost]

Locking this dead thread.