Question about Parity/Disk fail / Best configuration for my new UnRaid Server

[Ronan C]

Hello everyone, first, thanks for this great space to trade ideas and informations about UNRAID.

 

Im migrating my TrueNAS to Unraid, i just research a lot, and the good things that makes me decide for Unraid was the question about different disk sizes, but i have few questions, if any advanced user here can help me to solve this questions, i thank you in advance, here we go.

 

Hardware that i have avaliable for setting up:

 

Xeon 3.7 Ghz with dual gigabit LAN + 16 GB ECC RAM with 6 onboard SATA 3.0 PORTS

 

1x120GB SSD Brand New

 

4x 4 TB SATA DISKS (3 Seagate + 1 WD) (new)

 

and i have a 8 TB Disk brand new that are attached to my PC, i am thinking in setting up my UNRAID after i copy all data from the 8 TB disk to the Unraid pool, and after i can add this 8 TB drive to the Unraid server, in case will need to be as Parity drive, as the Unraid documentation says that need about the largest disk of the server needs to be the parity disk.

 

What the best settings i can use to setting up a great unraid array?

 

And the final question, i see everyone saying about the parity disks, as if i setup just one parity disk, i can "loose" one data disk on the array, but i didnt understanding this, causes the parity disk stores all parity info from all the data disks of the pool right?

 

Q1- When everyone means "you can loose 1 data disk" means, the 1 data disk can die, and all data still online and accessible? or the pool stops to working until i replease the faulty data disk?

 

Q2- If 2 data disks dies or got erros, i still can replease this two data disks and the parity disk (or disks if i setup 2 parity disks) can rebuild my data for this 2 new data disks? and in this cases, my array will ramain offline until the data disks got rebuilded by the parity disks?

 

Thanks everyone.

 

Ronan C

Brazil

 

 

 

 

[itimpi]

Q1:  with one parity disk then if a single array disk drive the system will emulate the failed drive and you can continue operating as if it is there (but with your data no longer protected)

 

Q2:   If you have 2 parity drives and 2 drives fail then the system will emulate both the missing drives and the array continue to operate.   If you have only a single parity drive and 2 array disk fail then Unraid cannot recover any of their data (although rescue utilities outside Unraid might have some success).

 

[Ronan C]

Thanks mate, i just setup my unraid, but i am still afraid of the trust about an unraid setup.

 

I used one 4 TB for parity and other 3 for data.

 

I did few tests but i didnt move my data to the array officially, i still have doubts about if its safe and trust 😞

One issue i found that its slow as hell, i just get around 50 M/B/s for writing, if i activate a cache SSD this get improved but my SSD its just 120 GB, so i decided to desactivaed, is there any Share configuration to improve the speeds of read/write on the array?

 

Once again, thanks in advance.

Ronan C

Brazil

[Hoopster]

1 hour ago, Ronan C said:

i just get around 50 M/B/s for writing

This is "normal" for a parity protected array with real-time parity updates as data is written to the array.

 

With Turbo Write enabled, you will get faster writes to the array at the expense of keeping all data disks spun up.  There is a plugin for enabling turbo write as needed.