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Sata card recommendation to increase parity sync speeds

glave

By glave
in Hardware

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glave Apprentice

glave

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My system has got 2 sata cards in it, a Promise 150 TX4 and a 300 TX4. I've got my parity and cache plugged into the motherboard itself, and the other drives into the 2 sata cards. Whenever I'm doing syncs, my throughput is only between 15mb-21mb. 10.5gb takes a little over 26 hours to finish syncs/parity checks.

 

I'm suspecting that the cards are bottlenecking so I wondered if I got a PCI-E sata card to replace my older ones if that could help speed things up a bit.

 

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SSD Mentor

SSD

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My system has got 2 sata cards in it, a Promise 150 TX4 and a 300 TX4. I've got my parity and cache plugged into the motherboard itself, and the other drives into the 2 sata cards. Whenever I'm doing syncs, my throughput is only between 15mb-21mb. 10.5gb takes a little over 26 hours to finish syncs/parity checks.

 

I'm suspecting that the cards are bottlenecking so I wondered if I got a PCI-E sata card to replace my older ones if that could help speed things up a bit.

 

 

Absolutely.  Your Promise cards are both on the PCI bus which maxes out at 133 MB/sec.  This is not a per controller limit - the entire bus maxes out at that speed.  With one drive on this bus you would get good performance on parity checks.  But every drive you add divides that 133 MB/sec.  With 6 drives on the PCI bus, you'd be down to 22 MB/sec (max).

 

Each "lane" on a PCIe card is capable of 250 MB/sec (or 500 MB/sec with 2.x spec slots).  So with a SASLP (very popular card here), you'd have 4x250MB/sec = 1000 MB/sec to share between 8 drives = 125 MB/sec. Plenty fast.  The other card I'd recommend considering is the IBM M1015 card.  It is an x8 card and would provlde 250 MB/sec for each of the 8 disks it supports.

 

If you do keep the PCI controllers, you'd give yourself a little parity check speed boost by exchanging slots with your largest array disk and your cache drive.  Since the cache is not involved in the parity check, it would mean one less drive contending for the PCI bus.

 

Also worth noting, the PCI bus speed is not split between all drives, only drives that are actively doing I/O.  So even if you had 20 drives on the PCI bus, if you were only reading from one of them, it would have the entire 133 MB/sec available.  So depending on your usage pattern, PCIe slots may not speed up your array in typical usage.  But it willl have a profound impact on your parity builds, parity checks, and drive reconstruction speeds.

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glave Apprentice

glave

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Each "lane" on a PCIe card is capable of 250 MB/sec (or 500 MB/sec with 2.x spec slots).  So with a SASLP (very popular card here), you'd have 4x250MB/sec = 1000 MB/sec to share between 8 drives = 125 MB/sec. Plenty fast.  The other card I'd recommend considering is the IBM M1015 card.  It is an x8 card and would provlde 250 MB/sec for each of the 8 disks it supports.

 

Well the IBM M1015 looks like a definite winner to me. Looking at it though, would this card need to go in the PCI-E x16 slot that would normally have a higher end video card? My board (Biostar TF720 A+) has 1 slot for that and 2 for PCI-E x1.

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SSD Mentor

SSD

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Each "lane" on a PCIe card is capable of 250 MB/sec (or 500 MB/sec with 2.x spec slots).  So with a SASLP (very popular card here), you'd have 4x250MB/sec = 1000 MB/sec to share between 8 drives = 125 MB/sec. Plenty fast.  The other card I'd recommend considering is the IBM M1015 card.  It is an x8 card and would provlde 250 MB/sec for each of the 8 disks it supports.

 

Well the IBM M1015 looks like a definite winner to me. Looking at it though, would this card need to go in the PCI-E x16 slot that would normally have a higher end video card? My board (Biostar TF720 A+) has 1 slot for that and 2 for PCI-E x1.

 

Yes - you would need to put the M1015 in your x16 slot (it needs x8 or faster slot to run at top speed).  Each of your 2 PCIe x1 slots can hold a 2 port controller (4 ports total).  So between these PCIe controllers and your 6 motherboard slots, you'd have 18 full speed ports.  You could add a PCI card for your cache disk and 1 (or even 2) array disks (your smallest ones) and get to a 21 drive setup.

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PeterB Proficient

PeterB

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Well the IBM M1015 looks like a definite winner to me. Looking at it though, would this card need to go in the PCI-E x16 slot that would normally have a higher end video card? My board (Biostar TF720 A+) has 1 slot for that and 2 for PCI-E x1.

 

Just be aware that some mother boards/chipsets really do dedicate the x16 slot for video use and other types of card do not work in that slot.  You will need to make enquiries as to whether your mobo is affected, or not.

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glave Apprentice

glave

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Just be aware that some mother boards/chipsets really do dedicate the x16 slot for video use and other types of card do not work in that slot.  You will need to make enquiries as to whether your mobo is affected, or not.

 

Yes, this part kinda worries me, and a very quick search before bed didn't turn up much info yet. I'll have to research for a bit and possibly just take the gamble.

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