Newb: Controller Question, Cage Question, and Parity/Cache Question


maximusfacq

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Hello All,

 

First post here. I built my first unRAID server on Thursday night and I am in process of copying files over to test the new system. So far, all is well and I am looking at moving forward with a Plus or Pro License purchase. I searched the forums already for an answer to this first question as I am sure it's already been asked. Unfortunately, I couldn't find what I was looking for, so here goes:

 

Regarding PCIe vs. PCI controller usage: Is it better to run with a PCIe x1 card vs. a PCI card?

 

My understanding is that to get the best yield from the setup that you ideally want at least a PCIe x4 slot to work with. My intention is to add to my build below by putting in 2x Adaptec 1430SA cards in the x1 PCI slots on my motherboard. However, if I'm not going to get any measurable performance increase from the x1 slot, I think I'd rather opt to go with 2 x Promise SATA 300 TX4 cards. What experiences have you folks had/read about with regard to this situation?

 

Second Question (Seen some debate on this, but nothing definitive):

Also debating between the Super Micro CSE-M35T-1B Cages and the Icy Dock MB674SPF-B Cages. I've read reviews that say the Super Micro cages are both Loud and Quiet? Which is it? I've read reviews that the Icy Dock Cages tend to be "flimsy" and Loud, but also quiet. So, which should I get and why? Nothing has convinced me yet...

 

Last Question:

I intend to purchase either a Western Digital Caviar Black WD2001FASS 2TB 7200 RPM 64MB Cache Disk or a Seagate Barracuda XT ST32000641AS 2TB 7200 RPM 64MB Cache disk to use as my parity drive and I have no clue what I want to do yet about a "cache" disk (Thinking either a SSD or another, smaller 7200 RPM Disk). Thoughts on these 2 decisions?

 

System Specs (Built from Legacy Gaming Rig):

Intel Pentium D 820

Intel D945PSN (http://downloadmirror.intel.com/15139/eng/D945PSN_ProductGuide03_English.pdf Diagram on page 11)

2x 1GB OCZ PC2-4300 OCZ25331024ELGEGXT

3x Western Digital Caviar Green WD20EADS 2TB 32MB Cache SATA

BFG GeForce 7800GTX (Crappiest spare video card I own  >.< )

Antec TruePower TP-650 650W

512MB Lexar Jump Drive  (unRAID 4.5.6)

 

I appreciate your time and feedback and look forward to being a part of this community!

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I'd rather not get a new mobo. At least, for now... Would a crappy PCI card suffice? I didn't really want to go that route without getting the answer to the PCIe x1 question.

 

Alternatively, I suppose I could drop the existing video card, put the Super Micro 8 port SATA card in the x16 slot, and then go PCI video....

 

Hmmmm.... more thinking... more debating....

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The typical PCI bus has 133 MB/sec bandwidth total available across all devices.

The typical 1 lane PCI Express has 250 MB/sec bandwidth available to that individual slot. If you use two 1x PCI Express slots, EACH SLOT has 250 MB/sec bandwidth.

 

If you use 1 PCI SATA card and place 4 drives on the PCI bus, your maximum limit will be 33 MB/sec [133 / 4].

If you use 2 1x PCI Express and place 2 drives on each, 4 drives total, your maximum limit will be 125 MB/sec [250 / 2].

If you use 2 PCI SATA cards and place 8 drives on the PCI bus, your maximum limit will be 16.6 MB/sec [ 133 / 8].

If you use 2 1x PCI Express and place 4 drives on each, 8 drives total, your maximum limit will be 62.5 MB/sec [250 / 4].

 

4 drives: 125 MB/sec (PCI Express) or 33 MB/sec (PCI)

8 drives: 62.5 MB/sec (PCI Express) or 16.6 MB/sec (PCI).

 

This limit occurs in the following situations, during parity builds, parity checks, failed drive situation, drive rebuilds, simultaneous writes, and simultaneous reads.

 

The choice is obvious.

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4 drives: 125 MB/sec (PCI Express) or 33 MB/sec (PCI)

8 drives: 62.5 MB/sec (PCI Express) or 16.6 MB/sec (PCI).

 

You should clarify that this theoretical limit is only during parity checks, and not regular usage.

 

Thanks for clarifying. I've written out responses to this so many times in the past week, I simply forgot to add that bit.

 

The performance impact comes into play during parity builds, parity checks, failed drive situation, drive rebuilds, simultaneous writes and simultaneous reads.

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