Raid-controller: grouping drives?

Hi everyone,

I'm surprised google turned up little or nothing on this type of question. :o
I'm looking to build my own NAS and I'm aiming for 10 * 2 TiB, probably going for raid 6.

I'm just hitting my 'gathering information' stage, and I've been looking at some custom setups. However, I've noticed the number of ports on the RAID-controller is fewer than the number of physical drives. So, some kind of mechanism must be used to group drives. I've found a controller with 4 ports.

Can anyone please explain how this grouping works?
6 answers Last reply
More about raid controller grouping drives
  1. What kind of drives are you raiding? SCSI or SATA? And can you link the controller you are looking at getting?
  2. hi endif,

    I'm a little behind on this particular subject (mass storage). I'll be RAIDing SATA drives for sure.

    Basically, a clever guy has made a similar project for a maximum of 20 drives. Apparently, I _think_ he has connected his drives directly to the motherboard using its onboard Raid controller. I don't want that (expandability is very low). you can take a look here:

    Now, I'm sure a 1 to 1 relationship exists between the number of drives that he connects to a backplane (as you can see in the pictures he made of it). From there on it becomes fuzzy. Do the 20 (!) cables from the backplane travel to a 20 port raid controller?How do the cables travel from the backplane to the controller? Does a backplane group drives per 4, making only 5 cables travel from the backplane to the raid controller. I found a controller boosting 24 ports but there were by no means 20 physical ports.

    So I'll either need a SATA-raid controller of a SAS-raid controller. I don't know which is best. So I'm basically stuck on how to connect the drives in an efficient way.

    PS: He is using this chassis
  3. To further clarify. This card appears to have 2 physical connectors

    Yet it supports 8 drives. How on earth does this work :D

    It seems to be using some "special' connectors called 2 SFF 8087 connectors.
  4. I just need more information about this post.
    :bounce: Seo Servises
  5. Please, feel free to tell me what exactly you need to know. I'm just trying to find my way to the rabbit hole.

    I will be stuffing a least 10 drives in a storage rack. Those drives will be SATA-drives (of course, hot swappable).

    My questions are mainly about the connectivity options between the backplane where the drives "plug-in" and the (SATA or SAS) RAID-card. Consider the question in 2 directions: performance wise and cable management wise.
  6. To save on cables from the RAID card to the Drive back plane you will want a back plane with an SAS/SATA expander. This will way you will only need a x4 lane SAS/SATA connection between the RAID card and the Back plane. You can alternatively just buy a Drive box that has an expander and the RAID card will be in a separate server.
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