Best layout

[kameleon]

Currently I am running a 8.3.0 install with 9x1TB drives in a raidz2 configuration. This yields me with approx 6.4TB usable after the disk formatting and losing 2 to parity. However I am quickly outgrowing this nas and am planning my next setup. The current setup has 6 SATA-II ports on the motherboard, an addon card with 2 SATA-II ports, and another one with 1 SATA-II port on it.

I plan to go with the latest freenas, of course. I have 8x2TB drives I would like to use. The motherboard I plan to use will accommodate up to 16GB of ram and has 8xSATA-III ports onboard. I was wanting to use the deduplication but I read that it needs 5GB per 1TB of data you want to dedupe. As it stands with my current setup I would need about 32GB of ram. Not to mention for the growth.

I am also wanting to set this one up for maximum performance. What would be the best layout for performance without losing half my storage. Once I migrate all the data off of the old system I plan to reuse some of the disks in the new setup as a separate array for other backups or similar.

For usage, I store all my Movies and TV shows on there for my Plex server. Along with using it as a nightly dump for my phone and other devices to backup to. I do plan to setup a server with a 4-tuner HD cable tuner that will be my DVR and will save to the NAS after encoding. That may make a difference in recommendations as for performance.

 

[cyberjock]

That 5GB per 1TB of storage is a rough estimate. If you run out of RAM you will NOT be able to mount your zpool under any circumstances until you have enough RAM to store your dedup table. There is no upper limit for how much you might need. Let me say that again.. there is NO upper limit for how much you might need. Maybe you understand why I tell people that choosing to use dedup for all but very small zpools is pretty much irresponsible.

Even the FreeNAS 8.3.0 release notes said:

ZFS v28 includes deduplication, which can be enabled at the dataset level. The more data you write to a deduplicated volume the more memory it requires, and there is no upper bound on this. When the system starts storing the dedup tables on disk because they no longer fit in RAM, performance craters. There is no way to undedup data once it is deduplicated, simply switching dedup off has NO AFFECT on the existing data. Furthermore, importing an unclean pool can require between 3-5GB of RAM per TB of deduped data, and if the system doesn't have the needed RAM it will panic, with the only solution being adding more RAM or recreating the pool. Think carefully before enabling dedup! Then after thinking about it use compression instead.

We've had a few people that tried it. Some had huge amounts of RAM(128GB+) and were able to utilize dedup to some extent. But for us mere mortals don't expect any sympathy if you use it and it backfires.

Sets of 8 drives in RAIDZ2 vdevs works well for most people. You could read the hardware recommendations and see some hardware that is recommended that supports 32GB of RAM and ECC with Intel NICs onboard. Can't go wrong with a 1-2-3 punch like that. M1015s are the controller of choice because a reflash to IT mode makes them exceptional SATA controllers for ZFS.