Griz Posted June 22, 2015 Share Posted June 22, 2015 I noticed that my parity checks are very slow (~30MB/s) for the first 1-2TB but then speed up to ~80MB/s once it gets past the smaller disks. When this has happened in the past, I would find a failing disk, remove it from the array and then things would be back to normal. I did have a failing disk and removed it from the array, but my parity checks are still slow at first. This is a 20 disk array with a mix of 1,2,3 and 6 TB drives. None of the drives have pending or re-allocated sectors. I could test the transfer rate of each 1 TB and 2 TB drive to find the slow one, but is there a smarter (or maybe SMARTer ) way to identify the culprit? Link to comment
Frank1940 Posted June 22, 2015 Share Posted June 22, 2015 I noticed that my parity checks are very slow (~30MB/s) for the first 1-2TB but then speed up to ~80MB/s once it gets past the smaller disks. When this has happened in the past, I would find a failing disk, remove it from the array and then things would be back to normal. I did have a failing disk and removed it from the array, but my parity checks are still slow at first. This is a 20 disk array with a mix of 1,2,3 and 6 TB drives. None of the drives have pending or re-allocated sectors. I could test the transfer rate of each 1 TB and 2 TB drive to find the slow one, but is there a smarter (or maybe SMARTer ) way to identify the culprit? What you are using as a SATA expansion card? Is it a PCI-E x4 or x8 card? PCI cards are throughput limiting with more than a couple of drives attached to them. Look at the rotation speed of your small drives. The effect of lower spindle speeds is more pronounced with low captivity drives than with high capacity drives. Link to comment
Griz Posted June 22, 2015 Author Share Posted June 22, 2015 It's one of those old TAMS Supermicro servers Motherboard: X7DBE-X Procs: Qty 1 Intel 5130 Dual Core 2.0GHz Ram: 8GB 4x 2GB, 12 empty slots Qty 3 SAT2-MV8 Raid cards Some of the smaller drives are WD Greens, so I know they are slow, but the parity check is slower than normal at the moment and I suspect that one of the drives has an issue that isn't showing up in the smart report (or I'm not educated enough to identify it). Link to comment
Frank1940 Posted June 22, 2015 Share Posted June 22, 2015 It's one of those old TAMS Supermicro servers Motherboard: X7DBE-X Procs: Qty 1 Intel 5130 Dual Core 2.0GHz Ram: 8GB 4x 2GB, 12 empty slots Qty 3 SAT2-MV8 Raid cards Some of the smaller drives are WD Greens, so I know they are slow, but the parity check is slower than normal at the moment and I suspect that one of the drives has an issue that isn't showing up in the smart report (or I'm not educated enough to identify it). Since you are running ver6, to to the 'Tools' tab, click on the 'Diagnostics' icon, 'Collect' the data and attached the file to your reply. Link to comment
garycase Posted June 22, 2015 Share Posted June 22, 2015 Interesting. There's another thread where the newer versions of that card -- the SAS2LP-MV8 -- has been having very slow parity checks with v6 as well. Not sure if this is related, but it may be ... and if that's the case, it likely has nothing to do with your drives. This is the thread: http://lime-technology.com/forum/index.php?topic=39125.0 Link to comment
Griz Posted June 22, 2015 Author Share Posted June 22, 2015 Interesting. There's another thread where the newer versions of that card -- the SAS2LP-MV8 -- has been having very slow parity checks with v6 as well. Not sure if this is related, but it may be ... and if that's the case, it likely has nothing to do with your drives. This is the thread: http://lime-technology.com/forum/index.php?topic=39125.0 Hmmm, that's not comforting. I just updated to v6 a few days ago and noticed this issue when doing a parity check to confirm that everything was OK after the upgrade. It was running ~30MB/s up to around 500GB. I went to bed and when I woke up it was running ~80MB/s at around 2.5TB, so I just assumed that one of my 1TB or 2TB disks was having an issue. If it is a SAS2LP-MV8 issue, perhaps it has something to do with loading, so as the parity check proceeds past the smaller disks, it gets faster. Link to comment
BobPhoenix Posted June 22, 2015 Share Posted June 22, 2015 Interesting. There's another thread where the newer versions of that card -- the SAS2LP-MV8 -- has been having very slow parity checks with v6 as well. Not sure if this is related, but it may be ... and if that's the case, it likely has nothing to do with your drives. This is the thread: http://lime-technology.com/forum/index.php?topic=39125.0 The SAS2LP-MV8 is a PCIe card the SAT2-MV8 is a PCI-X card. So I wouldn't necessarily call it a newer version myself. Link to comment
BobPhoenix Posted June 22, 2015 Share Posted June 22, 2015 It's one of those old TAMS Supermicro servers Motherboard: X7DBE-X Procs: Qty 1 Intel 5130 Dual Core 2.0GHz Ram: 8GB 4x 2GB, 12 empty slots Qty 3 SAT2-MV8 Raid cards Some of the smaller drives are WD Greens, so I know they are slow, but the parity check is slower than normal at the moment and I suspect that one of the drives has an issue that isn't showing up in the smart report (or I'm not educated enough to identify it). Use the MB ports and use 2 SAT2-MV8s one in the 133Mhz PCI-X port and NO other cards plugged into any other 133Mhz ports. The other SAT2-MV8 should be plugged into a 100Mhz PCI-X port with NO other cards plugged into 100Mhz PCI-X ports (assuming the X7DBE-X has similar PCI-X slots to my X7SBE anyway). I bet your speeds will increase. PCI-X is a much slower bus that PCIe but it is still much faster than a PCI slot. Link to comment
garycase Posted June 22, 2015 Share Posted June 22, 2015 Interesting. There's another thread where the newer versions of that card -- the SAS2LP-MV8 -- has been having very slow parity checks with v6 as well. Not sure if this is related, but it may be ... and if that's the case, it likely has nothing to do with your drives. This is the thread: http://lime-technology.com/forum/index.php?topic=39125.0 The SAS2LP-MV8 is a PCIe card the SAT2-MV8 is a PCI-X card. So I wouldn't necessarily call it a newer version myself. I suppose it's a semantic distinction; but I'd certainly think upgrading from a PCI-X to a PCIe bus was a significant improvement ... thus a "newer" version. Link to comment
ohlwiler Posted June 22, 2015 Share Posted June 22, 2015 I'd like to Echo what Bob stated and add a few extra pointers. Use all six motherboard ports and use more ports on the SAT2-MV8 that is plugged into the 133 slot. (Say 8 drives on the 133 and 6 drives on the 100). When assigning disks interleave them so disk1 is connected to SAT2-133, disk2 is connected to SAT2-100, disk3 is connected to a motherboard port, disk4 is connected to SAT2-133, etc. The SAT2 is a fine card. It had more bandwidth than a SAS-LP when I compared the two (Maybe ~15% more when alone on the 133 buss). Optimize your disk collection. Try to use as few sizes as possible. If you only have one of a particular size, target that one for an upgrade. I suspect your 1TB drive(s) are capping your speeds, but only for the first 17% of parity checks. Link to comment
Recommended Posts
Archived
This topic is now archived and is closed to further replies.