Raid Controller vs FreeNAS Raid

[vgarza]

Maybe this is a basic question but I will appreciate your advice.

I am going to build a FreeNAS but I do not know if is better to create a Raid10 from the server controller or just leave all drives without raid and make and manage the raid on the FreeNAS?

My understanding is that if I make the Raid from the server (controller) I won't be available to add higher disks and with the FreeNAS, I will be able to increase the same raid with higher disks, is this correct? or what can you recommend me?

Thanks in advance.

 

[rvassar]

The short answer: The ZFS filesystem requires direct access to the disk hardware.

RAID controllers effectively "hide" the disks, and present a blob of block storage that ZFS has difficulty effectively using. Many of us here have LSI RAID cards in our systems, but they've had their on-board firmware flashed to "IT mode", and act as simple disk controllers and present each disk individually to FreeNAS. The ZFS filesystem implements "pools" of storage, with configurable levels of redundancy, and we then create datasets on top of those pools.

There's a quite a bit of information for you to read up on. Suggested links:

https://www.ixsystems.com/community/resources/uncle-festers-freenas-beginners-guide.120/

https://www.ixsystems.com/community/resources/introduction-to-zfs.111/

https://www.ixsystems.com/community/resources/freenas®-quick-hardware-guide.7/