shooga Posted February 20, 2015 Share Posted February 20, 2015 I have a combination of (2) SATA III, (4) SATA II, and (4) SATA I ports on my motherboard and PCI card. It seems obvious that my cache drive should be on SATA III, but what about the parity drive? Will I get better performance with the parity drive on SATA III? Or is it CPU bound so I should actually just put it on one of the SATA I ports? Maybe I'm over thinking this because the bottleneck is the gigabit ethernet connection? The SATA I ports on are on a PCI card. Is it risky to put the parity drive on a PCI card that could fail? I'm in the process of an upgrade to some of my drives so any advice on how to use this combination of ports would be much appreciated. Quote Link to comment
itimpi Posted February 20, 2015 Share Posted February 20, 2015 I would put the largest drives on the highest rated SATA ports. The larger drives will almost certainly have higher areal density on their platters and thus be the most likely to benefit from higher SATA speeds. As far as the cache drive is concerned I suspect it does not make much difference whether it is on SATA II or III. If it is SSD then go for SATA III. You do not mention what PCI card, but I suspect that is the one which is most likely to be bandwidth limited, so try and limit the number of drives connected to it. Parity checking/calculation will not be CPU limited unless you have a very slow processor. It is nearly always dominated by the disk throughput. Quote Link to comment
garycase Posted February 20, 2015 Share Posted February 20, 2015 As itimpi noted, if you have an SSD in the mix (perhaps a cache) be sure it's connected to a SATA III port. As for the other (spinning) drives ... => Agree you want the drives with the highest areal density on the SATA II and SATA III ports (it doesn't matter which -- SATA II is faster than any spinning drive, so except for the trivial % of transfers to/from the drive's buffer, there's no difference in performance between SATA II and SATA III with traditional drives). => SATA I ports are fine for drives with areal densities < 1TB/platter. If you do as itimpi noted and simply put your oldest/smallest drives on these ports, you'll most likely meet this criteria (the exception would be if you've purchased newer "smallish" drives - e.g. a 1TB or 2TB WD Red still has 1TB platters). => As itimpi noted, a PCI card will likely cause bandwidth limitations due to the bus far before the SATA port speed comes into play. If possible, do not connect more than 2 drives to this card. Quote Link to comment
shooga Posted February 21, 2015 Author Share Posted February 21, 2015 Thanks for the advice guys! The SATA card I have is a 4 port Silicon Image card from monoprice. Is there a 4 port PCIe card that you'd recommend as an upgrade? The card that itimpi has is a bit overkill for me as I don't have room for 4 more drives in my case. Thanks again! Quote Link to comment
itimpi Posted February 21, 2015 Share Posted February 21, 2015 Thanks for the advice guys! The SATA card I have is a 4 port Silicon Image card from monoprice. Is there a 4 port PCIe card that you'd recommend as an upgrade? The card that itimpi has is a bit overkill for me as I don't have room for 4 more drives in my case. Thanks again! Are you sure that is a PCIe card? It looks like a straight PCI card from the description (and thus likely to be Bus throughput limited) if it has all 4 potential drives attached. Quote Link to comment
SSD Posted February 21, 2015 Share Posted February 21, 2015 A little old but explains the limitations of PCI controllers. LINK Personally I would not recommend using ANY PCI controllers on a modern array. If you have to - one drive and the cache disk on the PCI bus. Quote Link to comment
shooga Posted February 21, 2015 Author Share Posted February 21, 2015 It's definitely not PCIe, but it's been totally reliable (albeit slowly) for years now. That's why I was asking about an upgrade. The motherboard I have is an Asrock Z77m so I have PCIe x16 slots that I could use. I've been doing a little research and I don't see an obvious card that seems like a unanimous choice. This one looks good on paper, but there isn't much about it on the forums except for one person who says it may not support drives over 3TB. Quote Link to comment
itimpi Posted February 21, 2015 Share Posted February 21, 2015 Just a thought - the card you pointed at is a RAID card. Since you would end up disabling any RAID features to use it with unRAID it might be worth seeing if there is a cheaper version without RAID support. Quote Link to comment
Squid Posted February 21, 2015 Share Posted February 21, 2015 Just a thought - the card you pointed at is a RAID card. Since you would end up disabling any RAID features to use it with unRAID it might be worth seeing if there is a cheaper version without RAID support. My very first unRaid system had a couple of those cards in it. While it may say RAID right on it, it is software RAID only. They work just fine in unRAID (was using 3 of them at one point with 12 disks - very slow parity checks lol) Quote Link to comment
WeeboTech Posted February 21, 2015 Share Posted February 21, 2015 Before purchasing a 4 port PCIe card, I might consider a used 8 port LSI or supermicro x8 card. It will be a bit more, but in the long run you'll have expansion and speed. Possibly, Retire the PCI card and move the fastest & largest drives to the 8 port card. Anything on the PCI card is limiting your highest potential parity check speed. I might relegate / reassign this card to be used for external eSATA backup drives. (With pci eSATA brackets). SATA III matters for SSD. Parity and cache will benefit slightly on SATA III if they are high density drives. While maximum sustained speed will be limited on spinners, the burst speed into the drive's cache will be at full speed. Quote Link to comment
garycase Posted February 21, 2015 Share Posted February 21, 2015 Thanks for the advice guys! The SATA card I have is a 4 port Silicon Image card from monoprice. Is there a 4 port PCIe card that you'd recommend as an upgrade? The card that itimpi has is a bit overkill for me as I don't have room for 4 more drives in my case. Thanks again! Are you sure that is a PCIe card? It looks like a straight PCI card from the description (and thus likely to be Bus throughput limited) if it has all 4 potential drives attached. He didn't say it was a PCIe card -- he said it was PCI Quote Link to comment
garycase Posted February 21, 2015 Share Posted February 21, 2015 The SYBA card you linked to earlier [ http://www.newegg.com/Product/Product.aspx?Item=N82E16816124060&cm_re=pcie_sata-_-16-124-060-_-Product ] would work fine -- with a PCIe v2 x2 interface it has plenty of bandwidth for 4 drives ... and it DOES support drives of any size (not sure where you saw a comment that indicated it might not). However, I agree with Weebotech -- since you're going to be using an x16 slot, you may want to go ahead and buy an 8-port card so you'll have more future expansion potential. Never know when you might want even more drives Quote Link to comment
shooga Posted February 21, 2015 Author Share Posted February 21, 2015 How important is x8 vs x4 for an 8 port card? I just saw that I could get a used AOC-SASLP-MV8 on eBay for $50. That's hardly more than the new Syba and with more ports and more speed. Quote Link to comment
itimpi Posted February 21, 2015 Share Posted February 21, 2015 How important is x8 vs x4 for an 8 port card? I just saw that I could get a used AOC-SASLP-MV8 on eBay for $50. That's hardly more than the new Syba and with more ports and more speed. I use 2 of those and have not noticed any throughput limitations. I would say go for it. Note that with that card you also need the 8087 SAS->SATA cables (1 for each 4 SATA drives) as the ports on the board are SAS and not SATA. Quote Link to comment
Squid Posted February 21, 2015 Share Posted February 21, 2015 How important is x8 vs x4 for an 8 port card? I just saw that I could get a used AOC-SASLP-MV8 on eBay for $50. That's hardly more than the new Syba and with more ports and more speed. Using hard drives (spinners), there will be no difference between x4 and x8. With fast Sata III SSD's, the x8 will be faster. Quote Link to comment
WeeboTech Posted February 21, 2015 Share Posted February 21, 2015 How important is x8 vs x4 for an 8 port card? I just saw that I could get a used AOC-SASLP-MV8 on eBay for $50. That's hardly more than the new Syba and with more ports and more speed. It only matters if you have high speed SATA III SSD's on the controller. Since the motherboard has two SATA III ports, you'll be OK. Quote Link to comment
shooga Posted February 22, 2015 Author Share Posted February 22, 2015 Thanks again guys! I ordered the AOC-SASLP-MV8 from eBay. Really appreciate all of the help. Quote Link to comment
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