hi, i am trying to diagnose slow write speeds to my unraid box, here is what im running hardware wise:-

 

proc AMD sempron 145 2.8Ghz

ram 4GB DDR3

mobo  Asus M5A78L-M LX v2

switch TP-LINK 8-port Gigabit Unmanaged Desktop Switch (TL-SG1008D)

 

im using the onboard gigabit nic, which looking at unraid syslog is detected as follows:-

eth0: Identified chip type is 'RTL8168E-VL/8111E-VL'

 

software wise im running unraid 5.0 rc8a licenced with a pro licence, i do have a parity drive and i do have a cache drive, but i dont have the cache drive assigned to any of the shares as i want to use this solely for plugins only, no caching, so writes are ALWAYS directly to the protected array.

 

im basically having write speeds that top out at 21MB/s read speeds are perfect and return around 75MB/s to 85MB/s which is great. one other thing to add is that im writing to the disk share not the user share, the destination drive im writing to is just over 50% full so i dont think its a problem with fragmentation/slow inner write speeds.

 

ive noticed that im getting dropped packets on RX (less than 1% of total packets), which makes sense in that its writes that are slow, things i have tried so far with no result:-

 

copying from source pc (windows 7) to another linux device on same switch

result - can write at full speed, thus ruling out source as issue and also switch

 

changed cat6 cable for another cable (cat5e this time)

result - same write speed, cannot seem to achieve write speeds above 21MB/s

 

checked source disk can achieve speeds higher than 21MB/s (sata drive)

achieved write speeds to another linux device (openelec) of around 56MB/s thus ruling out source drive

 

made sure issue is not related to SMB

copied using NFS from another linux device as source, same performance issue, this also strengthens argument that it ISNT related to source pc

 

added the noacpi flag as per suggestion in other threads

no change in write speeds

 

updated bios for unraid mobo

no change in write speeds

 

at this point my gut feeling is this is either unraid nic driver related or my mobo nic is faulty, my money is on the driver, any other suggestions as to how to solve this VERY welcome as im coming to the end of my dagnosis with no fix at present.

 

link to syslog just incase you guys want to take a look through:-

 

http://pastebin.com/KpJ3Tpwb

 

thanks.

ok still talking to myself here, what do they say about people who do that?? 

 

tried setting one of my user shares to use the cache drive, still seeing slow write speeds, so i guess this rules out slow parity drive and/or cpu parity calculations causing a bottleneck.

 

so my next attack is nic replacement, can anybody recommend a decent (relatively cheap) supported nic that def can handle full gigbit speeds, was thinking about a pci-e intel nic dont know which ones are fully supported by unraid though

 

couple of questions for anybody reading this, is anybody using a amd sempron 145 2.8Ghz process and seeing decent write speeds?, or using my motherboard ( Asus M5A78L-M LX v2) and seeing decent write speeds?.

 

thanks.

 

 

I have  a Sempron 145 system that writes to the array at about 43MBps.

I have  a Sempron 145 system that writes to the array at about 43MBps.

 

Thanks that's good to know one other question for you, slightly off topic, can you watch hd movies whilst a parity check is in progress? I've found this isn't possible, im assuming due to processor not being powerful enough.

 

I can either full rate blu-ray mkv rip or ISO during a parity check. The video takes longer to start but once it's palying it's fine.

I can either full rate blu-ray mkv rip or ISO during a parity check. The video takes longer to start but once it's palying it's fine.

 

hmm interesting, i am able to start a blu-ray mkv rip but it seems to consistently cut out part way through but only when a parity check or pre-clear are in operation. im beginning to wonder if this is nic related too, we shall see as i have a new nic on order, if this cures this issue as well i will be a happy bunny, thanks again for the feedback dgaschk

and the mystery continues, im now using a pci-e nic (intel) and still getting the same write speeds, even directly to the cache drive, so i managed to borrow a gigabit switch from work, tried this and still not difference, so im left now with the following to try:-

 

bios settings - perhaps cool and quiet is being a little bit over zealous?

replace cpu? underpowered? - i know there is a post above saying write speeds are fine but im running out of ideas?

replace mobo - again clutching at straws really but i cant think what else is left to try?.

 

any suggestions anyone?

 

What is the source of the copy?

What is the source of the copy?

 

It's windows 7 pc, also tried from a pc running linux (openelec) to unraid with the same result. Just for sanity I also tried it from a laptop running windows 7 on a different port on the switch with a different cable, same result.

 

Thank the lord I've solved the issue, was a bug in the bios, updated to latest version which only came out two weeks ago and problem gone phew! Thanks to everybody who posted

 

edit - or so i thought!, im beginning to think this is a thermal issue, reason im coming to this conclusion is that if i bring the server in from the garage (normal location) and bring it into the house and start it up and connect to the switch i can get decent write speeds, if i then shut it down and put it back in the garage and start it up i also have decent write speeds, but only for a short period, once the unit cools down due to the ambient temp (garage is around 15 C) im back to write speeds of 21MB/s.

 

things im going to try tonight:-

 

1. check psu fan - is this rotating when in the garage or is this powered down due to the cold, if so is this the source of the issue?.

2. turn of q-fan in bios - perhaps this is incorrectly throttling the sata/cpu thinking its hot when in actual fact is actually cold.

3. reset bios to defaults - perhaps me updating the bios has screwed something up.

 

its def a strange issue, never seen anything like this and ive been in the I.T. industry for over 15 years!