April 13, 201511 yr The SASLP-MV8 should be able to do parity sync at speeds around 100MB/sec so probably no need to rush into replacing that. I have 2 of them on my system both fully loaded with 8 drives each and that is the sort of speeds I am seeing.
April 13, 201511 yr Author Thanks for the info... just thinking ahead I would probably replace the motherboard. Hopefully that will improve the performance.
April 13, 201511 yr Definitely no need to change from the SASLP-MV8 to a SAS2LP-MV8 => in fact, the SAS2LP is a PCIe x8 card ... and one of your slots is an x4 slot (in an x16 physical connector) => so it would only have half of the lanes connected anyway. It's difficult to say exactly where the bandwidth constraints are; but from what you're seeing it sure sounds like one of your SASLP cards isn't getting the full bandwidth it should. Whether that's a defective card; a defective motherboard PCIe connector; or simply a card that's not fully engaged is hard to say. Did you reseat the cards before you started the current parity sync?
April 13, 201511 yr Author Definitely no need to change from the SASLP-MV8 to a SAS2LP-MV8 => in fact, the SAS2LP is a PCIe x8 card ... and one of your slots is an x4 slot (in an x16 physical connector) => so it would only have half of the lanes connected anyway. It's difficult to say exactly where the bandwidth constraints are; but from what you're seeing it sure sounds like one of your SASLP cards isn't getting the full bandwidth it should. Whether that's a defective card; a defective motherboard PCIe connector; or simply a card that's not fully engaged is hard to say. Did you reseat the cards before you started the current parity sync? Yes, i did.. I've just been searching for a motherboard with two pci-e x16 slots but looks like there's not much out there. Would that actually make a difference to performance ? 2 pci-e x16 slots over one pci-e x16 + 1 pci-e x4
April 13, 201511 yr Wouldn't make any difference at all => the SASLP cards are x4 cards, so any additional lanes won't be used anyway.
April 13, 201511 yr ... and before assuming you just need a new motherboard, be sure it's not simply a defective SASLP card. You can test those after the parity sync completes.
April 13, 201511 yr Author okay, cheers...i still my old SATA-controller cards so i'll test this after the parity sync.
April 13, 201511 yr Author ohh i forgot to post the system log after i restarted the parity sync - syslog attached syslog.txt
April 15, 201511 yr Author Update... I just accessed the webgui to check the parity sync status and i saw this.. 135 MB/sec :o
April 15, 201511 yr Clearly at this point the only drive involved in the sync is the 6TB parity drive ... and the speed is just fine. That confirms that your issue is a bandwidth issue with one or more of the other drives in the system -- but at this point there's no way of knowing which one(s). When the sync finishes, you should run a parity test to confirm all was well [unfortunately it will almost certainly encounter the same bandwidth issue, so will take a couple days] => and THEN you can try and isolate where the bottleneck is. I can provide a few suggestions as to how to do that ... but first get the sync done and a confirming parity test, so you know that everything's good in the array.
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