June 14, 201412 yr I've decided to replace my current NAS with an unRAID system. I've spent the last few weeks in research, and I'd like to list what I've come up and see if anyone has any comments. First, some background. I've been using ReadyNAS servers for the last 5-6 years, with my current system a Pro Business unit with 6 WD Red 3TB drives in a RAID 6 (dual redundancy) with 10 TB available. However, with 1300+ DVD and 250+ BluRay rips I was running out of space, and the only expansion option was to replace all 6 3TB drives with WD Red 4TB units. As this was going to run me abount $1000, a friend convinced me that building an unRAID server made more sense. The more I looked into it, the more I agreed with him. I particularly like having disparate sized drives, files wholly contained on single drives, and only needing the drive with the movie being watched having to be spun up. So, on to the system. First, I really don't need more than a simple file server. Probably 98% of the usage will be watching a movie via a Dune HD box, and that probably only a couple of times a day. The rest of the time the system will be basically idle. Second, I've got maybe 25+ TB of drives I can use in this, with most of them WD Red 2TB and 3TB drives, so I'm not including them within this list. With that said, this is what I came up with: Case: Norco 4224 PSU: SeaSonic M12II 750 SS-750AM2 750W Motherboard: SuperMicro MBD-X10SLL-F-O CPU: Intel Celeron G1850 Memory: Kingston 2x4GB 240-Pin DDR3 ECC Unbuffered SAS Controller: IBM ServeRAID M1015 SAS Expander: Intel SAS 24-port Expander RES2SV240 Note that all of the links above are to Newegg.com pages, but I actually got most of the items off of eBay. I also didn't list any of the cables I'll be needing, nor did I detail the quiet case fans and bracket I picked up. I should mention that I decided to go with the M1015 SAS controller and the 24-port expander, rather than three M1015 controllers. I did that because that means that I can get to 24 drives using only one PCIe slot for the M1015, as the expander can be separately powered without the need for an additional slot. (One of the 2 SAS connections to one of the 4-SATA backplanes, the other connection to one of the 6 SAS connectors on the expander, and the other 5 expander connections to the rest of the backplanes.) Anyway, that's what I've got planned. Any comments would be appreciated.
June 14, 201412 yr If you are only looking at a file server you should be served well, however if virtualization is a consideration for SAB, Sickbeard, etc then it may be somewhat limiting - mind you the worst you'd have to do is swap out the CPU. Also, it looks like your PSU is single rail, which is important. The only other point I'd make is I hope the ram you selected is supported - I have the same board and went through 2 different ram types before I found one that worked. I was able to return the 2, but had to pay restocking fees, which sucked. I don't know if it's just the specific board, but SuperMicro seems to be rather picky with ram. I can't comment on the SAS controller/expander as I use AOC-SAS2LP-MV8's instead.
June 14, 201412 yr Author If you are only looking at a file server you should be served well, however if virtualization is a consideration for SAB, Sickbeard, etc then it may be somewhat limiting - mind you the worst you'd have to do is swap out the CPU. Yeah, I actually thought about that. I probably paid twice what I needed to for a motherboard so I could replace the CPU if I had to, plus I really wanted the IPMI support. I'm also pretty hopeful that the memory I picked up will work, as I was careful to make sure the specs were the same as the 'tested' memory on the SuperMicro website. Won't know until I put it together, of course. Thanks for the comments!
June 14, 201412 yr If you are only looking at a file server you should be served well, however if virtualization is a consideration for SAB, Sickbeard, etc then it may be somewhat limiting - mind you the worst you'd have to do is swap out the CPU. Yeah, I actually thought about that. I probably paid twice what I needed to for a motherboard so I could replace the CPU if I had to, plus I really wanted the IPMI support. I'm also pretty hopeful that the memory I picked up will work, as I was careful to make sure the specs were the same as the 'tested' memory on the SuperMicro website. Won't know until I put it together, of course. Thanks for the comments! According to the Kingston site your memory is compatible with your MB.
March 23, 201511 yr I'm interested in a similar system - how did it turn out? Also, out of curiosity, is it possible to run a Xen VM with linux/windows desktop at all? I realize there won't be any graphics passthrough, just wondering if we can have something similar to the old "windows XP mode" style VM's for basic desktop apps?
March 25, 201511 yr I just saw this thread for the first time, with it having been bumped to the first page. I've built a few SAS-based unRAID servers over the last few months, and one thing I see in this proposed build is that 20 drives will be funneled through just one 4x6Gb/s SAS connection, reducing the per-drive throughput for "all-drive" array operations to at most 120MB/s.
March 25, 201511 yr If the limitation is in the 4 links of 6gbps each, then it would be 150MB/s rather than 120MB/s, wouldn't it?
March 25, 201511 yr My understanding is that there is overhead in those SATA/SAS connections, for error detection/correction among other things, such that it takes 10 bits per byte. Hence the lower number. In my experience I tend to see more like 110MB/s when saturating SATA/SAS connections with "too many" drives per channel. So there's a bit more overhead creeping in from somewhere.
March 25, 201511 yr ...110MB/s... Clarification: Over the last few months I've tested many combinations of SATA/SAS motherboards, controllers, port multipliers/expanders, enclosures and drives. For a SAS 4 x 3Gb/s connection (SFF-8087/8088) I typically see *at most* ~1.1GB/s aggregate throughput during unRAID's "all-drives" operations (Parity Check/Sync, Data Rebuild). This despite the math (as you point out) working out to 1.5GB/s (12Gb/s over 8 bits per byte). Most of this is due to the 10-bits-per-byte encoding I mentioned: https://en.wikipedia.org/wiki/8b/10b_encoding, that gets you from 1.5GB/s to 1.2GB/s The rest would seem to be due to various other small sources of overhead along the way, which I've yet to actually determine the details of.
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