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I want to build up a new server-config in a small SOHO environment for some virtual machines (VmWare Workstation), like Firewall/VPN or Win8-WS for external access, etc. Some VM’s will be heavily power consuming. The data are company-data. So the aim is to get security with RAID6 but as well useful HDD speed. Of course, a second backup method will be used… The config should survive the next 3-5 years. Therefore I am willing to spend a little bit more. I will use a “msi_Z77A-G45 Thunderbolt” motherboard which has vt-d capability (and I know, only 32 GB RAM).

Now my question is regarding available speed of such a RAID6 configuration (means 4 + 1 or 2 HDD’s). Even if currently with some struggles (currently missing WIN driver, etc) I could use an external Thunderbolt-RAID (Promise Pegasus R6), which is also seen on their website for small Server-Environments. They use 6 x Hitachi 2TB Deskstar 7k3000 (HDS723020BLA642). Not sure why they don't use streamline HDD's in such a 24/7 environment... So: no SAS and no streamline HDD…

On the other hand it may be better to use internal HDD's in a big ATX Case. So, if using a RAID Controller (LSI Logic MegaRAID SAS 9271-8i) on a PCIe 3.0 x8 slot with the same HDD's it would make a substantial cost reduction (nearly 50%).

But I am not sure about the performance. What would be your suggestions?

  1. is there a big difference between Thunderbolt and an internal PCIe x8 Card?
  2. if I would use an NAS (in a GB-Network) instead of a Thunderbolt, would it be possible to get similar performance?
  3. if using the internal LSI RAID, does it make a big difference using an SAS (means 3-4 x more expensive), please be aware that I am not a big company rather a Freelancer…
  4. is there an internal "Thunderbold"-RAID existing on the market

Thanks in advance for your comments.

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1 Answer 1

First of all: consider a pre-build server. While you can do it yourself and save money, you often spent a lot of time checking facts and fixing 'little but unexpected things'. If you compare time spent (hours times your salary times two) plus cheap HW cost vs pre-build things are suddenly a lot less cheap.

1) Is there a big difference between Thunderbolt and an internal PCIe x8 Card?

The internal PCIe x8 slot will be faster. Probably a lot fast though this depends on how many PCI-e channels your Thunderbolt controller uses (which does not seem to be listed on MSI's webpage). If you need that speed is another question. With only a few drives both are likely to be fast enough.

If I would use an NAS (in a GB-Network) instead of a Thunderbolt, would it be possible to get similar performance?

No.

Ethernet is much slower than an internal RAID card or Thunderbolt.

If using the internal LSI RAID, does it make a big difference using an SAS (means 3-4 x more expensive), please be aware that I am not a big company rather a Freelancer…

SAS is not per definition faster than SATA. SAS drives have these advantages:

  • Often build in higher quality.
  • Available with higher spindle speeds. (Faster if you get these high RPM drives. 7200RPM SAS vs 7200 RPM SATA should be about the same).
  • More graceful failure.

Higher quality drives is important. Regardless of which drives you use, select these careful.

Spindle speeds is about price vs performance. 15K RPM drives will faster than 7200k RPM SATA drives. But if I can get twice as many SATA drives for the same price and stripe them (e.g. in RAID 10) then you might get better performance with more but slower SATA drives.

Graceful failure is important is you use port multipliers. (Think of these as 'splitters') . I single SATA drive failing might well take down the whole array. I single SAS drive failing would just drop the drive.

The RAID card you mentioned has room for up to 8 drives without using these. So unless you plan to extend beyond 8 drives this is not important to you.

4) Is there an internal "Thunderbold"-RAID existing on the market

Yes, Google for "thunderbolt raid enclosure". (I will not mention specific brand here. but you will find multiple).

How many drives are you planning to use? And which RAID level? You want to think about that before buying anything.

Example things to consider:

RAID 6: 4 drives -> 2 drives capacity available) (easy to expand to 5 drives)
RAID10: 4 drives -> 2 drives capacity available) (Faster than RAID 6)

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Hi, would llike to vote, but it's not possible for me, thanks for the answer! You are right regarding time/costs, but currently I don't have a project, so time isn't that important ;-) I am planning RAID6, (most likely 1 or 2 HDD for security, depends on the case). ..."internal PCIe x8 slot will be faster", oh - I was searching but was not able to find a comparing review between both technologies. Do you have an example where this is more elaborated or some general links? ..."TB Raid enclosure", yes I know Promise, Drobo, etc - but my idea was not to use an external but the Server case itself. –  jochen thomas Nov 27 '12 at 14:45
    
Hi, 1) RAID 6 is always used 2 drives against failure. If you use that with a single drive it is called RAID 5. *) Search on Thunderbolt and you will find that it is mostly a single PCIe lanes tunnels over another interface. Depending on the chips use the TB interface is fed with 1 or 4 PCIe lanes. An internal x8 would be 8 (8x1) or 2 (2x4) times faster, assuming the same PCIe version. And I do not think they used the few rare PCIe v3 lanes for those, so the the speed difference will be even larger. (And that is with ignoring extra latency from converting vs native). –  Hennes Nov 27 '12 at 18:28
    
As for the last part. I am not sure I understand that. Pure internal with RAID would be PCIe -> RAID card -> drives. Via TB it would be PCIe -> PCIe_to_TB -> cable -> TB_to_PCIe -> RAID card -> drives. The only reason to do that is if you want something external. If internal use a normal PCIe slot. (See also intel.com/content/dam/www/public/us/en/images/diagrams/…) –  Hennes Nov 27 '12 at 18:30
    
Hennes, sorry regarding RAID6, you're right. And ...I haven't build up an own server since years, so - please forgive me :-)), I was reading about the fastness of Thunderbolt and compared against other options... (maybe was mislead) –  jochen thomas Nov 27 '12 at 19:27
    
TB is the fastest external option there is. It is just that there are much faster internal options. –  Hennes Nov 27 '12 at 21:16
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