We are running out of space on our existing system and need some advice on how to expand/rebuild. This is an archiving system for media files (200 MB and up mostly) with what I consider low to moderate but probably constant reads and very low writes (only when something new is added)
We currently have:
HP Proliant N40L
Build FreeNAS-8.2.0-RELEASE-p1-x64 (r11950)
Platform AMD Turion(tm) II Neo N40L Dual-Core Processor
2x WD-WMC1 3TB hard drive
2x WD-WCA 3TB hard drive
Arranged in a single ZFS raid volume
FreeNAS 8 booting off of a 4GB USB thumbdrive
Because the ZFS RAID volume is not expandable we need to change it. We plan on copying off everything stored on the current RAID and rebuilding the entire system. Obviously as our data grows this will be impossible to do again as we won't have enough free space on existing drives to handle the amount of data.
What we want:
We want a system that we can add drives to, preferably different size drives as technology improves. We also would like to have some protection against drive failures (RAID 5 or 6 or similar). Yes, in a perfect world money would be no object and we'd be able to set up a mirrored system with full backups but that is not going to happen.
What we were thinking (the reason we're in this forum) is to use Synology DSM (from a USB stick) and create a SHR (Synology Hybrid Raid).
I figured we'd buy a controller card for expansion so we can add (for now) 4 more drives of 4 TB and add a 5th drive in the currently unused optical drive space with all 8 (or 9) disks probably with 2 disk redundancy. The new drives would be in an external tower as they can obviously not fit in the microserver.
What we need to know:
1. What kind of controller card should we use? Is there a limit to what DSM can support?
Never used a controller card before. Anything particular to consider in the installation, special cables or anything special for the tower we use?
2. How many drives can we add to our RAID (either single or double parity) before the risks become too great or we hit capacity limits of the N40L (Memory/CPU)? Obviously the more drives, the less percentage space used for parity which we like but where is the limit (for Raid 5 or 6 or similar)? When does one just say enough and create new RAID volumes or buy a new micro server?
Lots of new kinds of hard drives what would be suitable for this purpose? Obviously cost is very important as well but are the new NAS drives worth it?
3. Is it better to install the new 4TB drives internally or to the controller card or doesn't it matter?
4. Is there any difference using 2TB or 3TB drives together with 4TB is either of them better (besides more space)?
5. Can Synology DSM be installed to boot off of the USB thumb drive leaving the SATA disks free for storage?
6. Must all drives be added simultaneously and if not, if what ways can they be added?
7. I know that DSM itself cannot be automatically updated, but can the packages be updated?
We currently have a Synology DS411j with 4x2TB disks in a SHR volume using DSM3.2, so we are familiar with the basics of Synology and DSM, which is largely why I want to also use it on our Proliant microserver.