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I have four HP 600GB 10K 2.5" SAS HDD Drives and I want to buy a SAS controller to connect them to my PC (ASRock Z97Extreme6 Motherboard).

My requirements are:

  • They will run under software RAID 1 or 10 under Linux
  • There will be no more that 4 HDD attached
  • My motherboard has 2 PCIe 3.0 x16, 1 PCIe 2.0 x16, 2 PCIe 2.0 x1
  • I plan to put several VirtualBox VM's on this storage.
  • PC is used as workstation

I do not know how fast those disks are, but I do not expect read/write speed more than 120MB/s. Can I use PCIe 2.0 x1 slot for SAS controller?

Do I need four separate internal connectors? Does it matter if controller has single connector or more in terms of performance in my case?

Can you advise some model that will meet my requirements?

Lukasz
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2 Answers2

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but I do not expect read/write speed more than 120MB/s

140-170 MB/s (linear write) are archivable with SAS disks

Can I use PCIe 2.0 x1 slot for SAS controller?

Almost any card I've seen so far is x4 or x8 - I assume a x1 to x16 riser wont work with SAS controllers. Be aware, that SAS controllers are sometimes quite sassy about the port requirements: I've seen controller, that only worked in PCIe2 ports not in PCIe3.

Do I need four separate internal connectors?

No, with the requirement of max. 4 disks a controller with one SFF-8087 port (and the extending cable for connecting the 4 disks) or a controller onboard ports would be sufficient for you.

Does it matter if controller has single connector or more in terms of performance in my case?

I guess no, because a SAS controller should be able to deliver full speed on every port (No port-multiplying considered!).

Can you advise some model that will meet my requirements?

See above. At my place i have currently a Adaptec RAID 3405 and LSI SAS3444E - both would suit your needs and I cant complain about them.

Henrik
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  • Ok, I found LSI3442E on local auction site but seller contacted me telling that there is a problem with it and he will send me HP P400 with BBU instead (cache size unknown). So now I have dilemma - should I go with mdadm as I planned or try to use HW RAID with P400 :-) – Lukasz Aug 13 '15 at 09:04
  • As far as I can see, theres no reason to not use the raid 10 via the P400. Where do you see the dilemma? – Henrik Aug 13 '15 at 12:10
  • Ok, I misunderstand how BBU and write cache works. It looks like I can setup simple non-raid configuration with this P400 and still benefit from having 256MB write cache and them use mdadm to create RAID array. According to http://h30499.www3.hp.com/t5/System-Administration/P400-RAID-scrubbing-verifying-howto/td-p/4034877#.Vc3GunVq1FQ it looks like P400 has very slow array verification. – Lukasz Aug 14 '15 at 10:45
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Please see: How exactly does a SAS SFF-8087 breakout cable work? + RAID/connection questions

But any SAS controller of value is going to require a wider PCIe slot width. You have a couple of x1 connectors, but what is their physical size?

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ewwhite
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  • Lokking at http://pclab.pl/zdjecia/artykuly/vega/2014/kwiecien/asrock_z97_8.jpg their size is x1 – Lukasz Aug 07 '15 at 07:52