New server configuraton.

[Cristisn Todosi]

Hello all,
I am building a new FreeNAS server I am hopping to get some help configuring the storage.
The serve has an older processor (Intel(R) Xeon(R) CPU E5-1620 v3 @ 3.50GHz), 64GiB of RAM and 24 disks of 3TiB (plus one SSD for the OS).
This server will be used mostly to serve iSCSI devices for some Linux VM's and samba servers.
What is the best way to configure the storage? How many pools shuld I create (I was thinking to create 2 pool 11 disks each plus one spare)? Should I enable any other services?
Thank you for your time!

 

[c77dk]

This server will be used mostly to serve iSCSI devices for some Linux VM's and samba servers.
What is the best way to configure the storage? How many pools shuld I create (I was thinking to create 2 pool 11 disks each plus one spare)? Should I enable any other services?

When you write pool - do you mean vdevs? or real pools?

Given you want to share iscsi I would suggest going for 11 (2-way)mirror vdevs in one pool, and have two spares, but it depends on the capacity needed, and also the redundancy needed. With the suggested setup your pool is toast if the two disks in one mirror die at the same time.

 

[Heracles]

Hey Cristisn,

For iSCSI and VM, mirrors is the way to go. So here, it means 12 mirrors built with 2 drives each.

How much storage space do you need ? These 12 mirrors would give you 12x 3 = 36TB of usable space. If that is way more than needed, you can go with 3 way mirrors : 8 mirrors made with 3 drives each. More drive per mirror will speed up reads and will also offer greater protection, allowing 2 drives to fail in a single mirror. That would give you 8x 3 = 24TB of storage space.

About pools, you normally put everything in a single pool, except if you need to use different pool-level options. That is pretty rare and I doubt it would apply to your situation. So a single pool is probably what fits you the best.

As for services, just enable the ones you need. You mentioned iSCSI and Samba. If you do not need more, do not enable more...

Have fun designing your system,

 

[Cristisn Todosi]

When you write pool - do you mean vdevs? or real pools?

Given you want to share iscsi I would suggest going for 11 (2-way)mirror vdevs in one pool, and have two spares, but it depends on the capacity needed, and also the redundancy needed. With the suggested setup your pool is toast if the two disks in one mirror die at the same time.

Thank you for replaying.
My initial thought was to to build two real pools (sorry for the typo) with RAIDZ3. My problem now is that I already built another server with this configuration and I've migrated the data from this one.. Our requirements are space and redundancy not high speed.
Thank you again for your time!

 

[Heracles]

Thank you for replaying.
My initial thought was to to build two real pools (sorry for the typo) with RAIDZ3. My problem now is that I already built another server with this configuration and I've migrated the data from this one.. Our requirements are space and redundancy not high speed.

Well.. If you ask questions, be ready to receive the answer...

A single 24 drives Raid-Z3 is not recommended. It is way too large. It is not that performance will not be high, performance will be plain terrible. Also, the redundancy you said was important is not that high... You will be safe for the lost of the first 2 drives out of 24. That is only one out of 12, so 8.5%. The pool should survive the loss of a third one, but should anything goes wrong during the resilvering process, the pool may end up corrupted because there is no more redundancy to detect / fix the problem.

You should not do less than 2x 12 drives Raid-Z2 vDev. Even that would be over stretched.
2x 12 drives Raid-Z3 would be more reasonable for redundancy but still very poor performance.
With these 6 drives used for redundancy, 3x 8 drives Raid-Z2 would give you the same storage space and redundancy with a better performance.

Also, about redundancy, remember that no server, FreeNAS or other, Raid-Z3 or other, can be more than a single point of failure. You must design a complete backup plan for your data if you are not ready to lose them all.

 

[MRBIQ]

@Heracles all your words right really