May 27, 201313 yr Hi I have recently upgraded my unraid machine with newer hardware and I am getting incredible read speeds (~150 MB/s) but terrible write speeds (~180 kB/s). I am running Unraid version 5.0-rc12a below is a chart of my devices and their speeds: backplane ata# sdX device Name Read Write ---------------------------------------------------------------------------------------------- No ata9 sdh cache Crucial M4 SSD 361 MB/s 174 kB/s ICY Dock (a) ata8 sdg disk1 WD30EFRX 147 MB/s 336 kB/s ICY Dock (a) ata7 sdf disk2 WD30EFRX 148 MB/s 189 kB/s ICY Dock (a) ata1 sda disk3 WD30EFRX 146 MB/s 124 kB/s ICY Dock (b) ata5 sdd disk4 WD30EFRX 156 MB/s 184 kB/s ICY Dock (b) ata3 sdb disk5 WD30EFRX 154 MB/s 178 kB/s ICY Dock (b) ata6 sde disk6 WD30EFRX 149 MB/s 374 kB/s ICY Dock (b) ata4 sdc disk7 WD30EFRX 154 MB/s 182 kB/s N/A USB usb3 sdj flash Storage_Media 10.7 MB/s 298 kB/s I got the read speed values by using this command: dd if=/dev/sdX of=/dev/null count=8192000 (X is replaced with a, b, c, etc) I got the write speed values by using this command: dd if=/dev/zero of=/mnt/[deviceName]/test.dd count=8192 ([deviceName] is replaced with disk1, disk2, cache, etc) I have removed all plugins except for unmenu and screen. I have 2 icydock backplanes. However I am getting the same terrible write speeds on the ssd drive that is connected directly to the sata port on the motherboard. All of the backplane sata connections are connected to the motherboard sata connections. The motherboard is an ASRock Z77 Pro. I just updated the firmware to the latest version (1.6). The cache drive is an SSD drive and the rest are all WD red drives. I have read that the parity drive should be a 7200 rpm drive. I have ordered one to see if that would help. However it wouldn't explain the slow cache drive performance. I have also tried both NCQ enabled and disabled with little effect. I have kept NCQ enabled since ssd drives need it. Since the terrible write speeds are consistent all across the board (USB flash, SATA mobo direct, SATA IcyDock Backplane, SSD) I don't think this is a hardware problem. I am thinking the problem is at the OS level. Do I need to use a newer sata driver that is not included with the latest unraid build? I am not very familiar with installing drivers on Linux systems. If it is a missing driver in the latest unraid distribution, how soon untill it will be included? I have also attached my system log. Let me know if I need to provide any other info. Thanks for your help JC syslog-2013-05-27.txt
May 27, 201313 yr Not a "Linux guy" ... so can't comment on whether or not your commands to measure the speeds are in fact correct. But what does Windows show for speeds if you write to one of the disks and read from the disk? That's more important anyway, as it factors in the network, which is obviously part of any "real" use of the array. Also, there's no significant advantage to using a 7200rpm parity drive. It will help some if you're doing simultaneous writes to the array from different clients; but won't impact your parity check speed => and it will draw more power and run hotter than the WD Reds.
May 27, 201313 yr Author Thanks for the fast response! I tried copying a 8 GB file over the lan to the cache drive. My write speed hovers around 1 MB/s. Then I tried copying the same 8 GB file to disk1 over the lan and the write speed hovers around 500 KB/s. Read speads from the same disk over the network are around 85 MB/s.
May 27, 201313 yr Hi I have recently upgraded my unraid machine with newer hardware and I am getting incredible read speeds (~150 MB/s) but terrible write speeds (~180 kB/s). I am running Unraid version 5.0-rc12a below is a chart of my devices and their speeds: backplane ata# sdX device Name Read Write ---------------------------------------------------------------------------------------------- No ata9 sdh cache Crucial M4 SSD 361 MB/s 174 kB/s ICY Dock (a) ata8 sdg disk1 WD30EFRX 147 MB/s 336 kB/s ICY Dock (a) ata7 sdf disk2 WD30EFRX 148 MB/s 189 kB/s ICY Dock (a) ata1 sda disk3 WD30EFRX 146 MB/s 124 kB/s ICY Dock (b) ata5 sdd disk4 WD30EFRX 156 MB/s 184 kB/s ICY Dock (b) ata3 sdb disk5 WD30EFRX 154 MB/s 178 kB/s ICY Dock (b) ata6 sde disk6 WD30EFRX 149 MB/s 374 kB/s ICY Dock (b) ata4 sdc disk7 WD30EFRX 154 MB/s 182 kB/s N/A USB usb3 sdj flash Storage_Media 10.7 MB/s 298 kB/s I got the read speed values by using this command: dd if=/dev/sdX of=/dev/null count=8192000 (X is replaced with a, b, c, etc) I got the write speed values by using this command: dd if=/dev/zero of=/mnt/[deviceName]/test.dd count=8192 ([deviceName] is replaced with disk1, disk2, cache, etc) I have removed all plugins except for unmenu and screen. I have 2 icydock backplanes. However I am getting the same terrible write speeds on the ssd drive that is connected directly to the sata port on the motherboard. All of the backplane sata connections are connected to the motherboard sata connections. The motherboard is an ASRock Z77 Pro. I just updated the firmware to the latest version (1.6). The cache drive is an SSD drive and the rest are all WD red drives. You apparently have 32Gig of RAM. Am I correct? If so, read here: http://lime-technology.com/forum/index.php?topic=22675.msg225348#msg225348 reboot and use the 4Gig memory option in the boot menu. It will likely help a lot. I have read that the parity drive should be a 7200 rpm drive. I have ordered one to see if that would help.It will NOT help unless you are writing to a 7200 RPM data drive, or simultaneously writing to multiple 5400 RPM data drives. However it wouldn't explain the slow cache drive performance. Correct, parity disk is not involved with writes to the cache drive. Write performance to the protected disks in the array are ultimately limited by the slowest rotational speed drive involved ,since the disk platters MUST rotate in between the READ and then WRITE of the same sector on both the parity disk and the data disks involved. See the above link for current issue when > 4Gig of memory present on some hardware. I have also tried both NCQ enabled and disabled with little effect. I have kept NCQ enabled since ssd drives need it. Probably will not make a difference in speed. You can experiment. There are some disks with a firmware bug that lost data if NCQ was enabled and you invoked either a smartctl or hdparm command. You might want to make sure you don't have one of that model disk. Since the terrible write speeds are consistent all across the board (USB flash, SATA mobo direct, SATA IcyDock Backplane, SSD) I don't think this is a hardware problem. I am thinking the problem is at the OS level. Do I need to use a newer sata driver that is not included with the latest unraid build? I am not very familiar with installing drivers on Linux systems. If it is a missing driver in the latest unraid distribution, how soon untill it will be included?If a driver was missing, you would not be able to get to the disk at all. There will be updates to drivers constantly in future releases of unRAID. Since the next release of unRAID is predicted in June, you could wait a few days to see what evolves.
May 27, 201313 yr Sorry for the duplicate post -- Joe L already noted the RAM issue. While your board isn't one of the boards I've seen listed with this problem, I (like Joe) suspect that's the issue. Hopefully this will be resolved in v5 Final.
May 28, 201313 yr Author That was it!!! Thank you sooo much. I never would have figured that out. Now cache drive write speeds are around 105 MB/s over the network. And writes to the protected array drives are around 30 MB/s. Thanks again! JC
May 28, 201313 yr That was it!!! Thank you sooo much. I never would have figured that out. Now cache drive write speeds are around 105 MB/s over the network. And writes to the protected array drives are around 30 MB/s. Thanks again! JC Glad that resolved it. I'm fairly sure there's a parameter you can add to your flash drive to force the 4GB mode at boot, but don't recall just what it is -- I'm sure Joe knows and will hopefully chime in Be sure you make that change to your flash drive, or you'll have to be at the console any time you reboot the system. ... and of course be sure to remove it when v5 Final is released [At least until you confirm that the issue is resolved !!]
May 28, 201313 yr Author I added the parameter in green in my syslinux.cfg on my boot flash drive. default menu.c32 menu title Lime Technology LLC prompt 0 timeout 50 label unRAID OS menu default kernel bzimage append mem=4095M initrd=bzroot label Memtest86+ kernel memtest Hopfully this limitation will be resolved in v5 final. In the mean time I can get by with only 4 GB. Thanks again for the quick response.
May 28, 201313 yr I added the parameter in green in my syslinux.cfg on my boot flash drive. default menu.c32 menu title Lime Technology LLC prompt 0 timeout 50 label unRAID OS menu default kernel bzimage append mem=4095M initrd=bzroot label Memtest86+ kernel memtest Hopfully this limitation will be resolved in v5 final. In the mean time I can get by with only 4 GB. Thanks again for the quick response. You're most welcome ... and thanks for this post -- I just saved the mod for a 4GB boot JUST IN CASE I ever encounter a system that needs it
June 9, 201313 yr Author I just wanted to provide an update. I decided to try RC13 and it appears the slow write issue for this board (ASRock Z77 Pro) has been resolved. I am able to use the full 32GB of RAM with expected write speeds.
June 9, 201313 yr I just wanted to provide an update. I decided to try RC13 and it appears the slow write issue for this board (ASRock Z77 Pro) has been resolved. I am able to use the full 32GB of RAM with expected write speeds. Tom said that was resolved in RC13 ==> nice to have confirmation
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