Best setup for 8x 4TB with 2 disk redundancy.

[helloha]

Just wondering what the best setup might be for 8x 4TB disks. I need at least 25TB of usable storage and 2 disk redundancy.

I was thinking of putting all 8 disks in a raidZ2 vdef and putting it all as one disk in a pool. But will this give me the best performance?

Right now with 3 x 4TB disks in Raidz2 I get 70MB writes and 350MB reads... I would like to get better writes... or should I put in an SSD cache?

THX for suggestions!.

[raulfg3]

if have the opportunity to do test, try:

2 vdev in one pool , each vdev 4x4TB in RaidZ1 ( yes only one disk redundancy per vdev, but 2 disk redundancy in pool, and probably better speed, try it).

[apollo567]

Hello,
Go at least for 16 Gb RAM perhaps up to 32 GB , and optimize the Configuration in the Loader Conf (Princo gave some very good Configuration tipps).
I have good Experiences with big Samba Cache of 1GB each for send and receive (reduces spikes and increases Speed)
For 25 GB real Space you will need more Disks. With RaidZ2 you will loose 2 disks and 8% for the File system, so u will need one extra disk.

Regards
apollo

[helloha]

if have the opportunity to do test, try:

2 vdev in one pool , each vdev 4x4TB in RaidZ1 ( yes only one disk redundancy per vdev, but 2 disk redundancy in pool, and probably better speed, try it).

So if 2 disks in one vdef fail you are out of luck?

[helloha]

Hello,
Go at least for 16 Gb RAM perhaps up to 32 GB , and optimize the Configuration in the Loader Conf (Princo gave some very good Configuration tipps).
I have good Experiences with big Samba Cache of 1GB each for send and receive (reduces spikes and increases Speed)
For 25 GB real Space you will need more Disks. With RaidZ2 you will loose 2 disks and 8% for the File system, so u will need one extra disk.

Regards
apollo

Hi, yes got 24GB of ram.

2x Xeon E5420

Do you have any links to the Princo tips?

Also perhaps important detail is that I'm running over AFP?

Cheers!
K.

[apollo567]

Hello,
here are the value for 8GB RAM, u have to adjust the first 3 topics for 24 GB. You have to add them in the loader Conf.

vm.kmem_size="6656M"
vfs.zfs.arc_min="5120M"
vfs.zfs.arc_max="5120M"
vfs.zfs.prefetch_disable="0"
vfs.zfs.txg.timeout="5"
vfs.zfs.vdev.max_pending="10"
vfs.zfs.vdev.min_pending="4"
vfs.zfs.write_limit_override="0"
vfs.zfs.no_write_throttle="0"

I have no experience with AFP (I don't use anything from apple ). If u use Samba, as mentioned I have good experiences with a very big cache.