Write performance issue

[paqmaster]

When I copy files to my Unraid server, I get these huge peaks and valleys in write transfer rate over my GigE network.  I'll get 30+ MB/s for about 1-3 seconds and it drops to zero for about the same about of time and this cycle repeats over and over again until the file copy is complete.  When I'm doing any sort of writes, I can't use the Unraid server for video playback since the video keeps freezing everything the write transfer goes to zero.  (The video is being played back from a different disk that's on a different controller or channel)

 

Rebooting the Unraid server does not help.

 

I'm using the same hardware as the Complete Unraid server that's sold by LT but with 1GB of RAM and only 8 drives.

 

Any idea what can be causing this?

 

Thanks.

[jesuslovesbacon]

I think it does that to everyone. Maybe it writes in one chunk, calculates parity, writes that, then goes for the next chunk?

[TCIII]

paqmaster,

 

I have seen the same kind of performance that you have seen during writes.

 

I first noticed this behavior when I was transferring ripped DVDs from my XP Pro server to my first unRaid server.

 

I could see the activity lights on my Linksys switch for each channel and the one from my XP Pro server to the unRaid server showed periodic burst of transfer activity and not a steady flow.

 

Regards,

TCIII

[jesuslovesbacon]

Like this?

 

 

[paqmaster]

Yup, pretty much like that.  Longer intervals on my GigE connection.  Sometimes it will stay bottomed out for up to 10 secs at a time.

 

Anyone know if this issue is going to be fixed in the upcoming release of the Unraid software?  Not being able to use my Unraid server for PVR files (since I can't read/write at the sametime without these transfer pauses) is hard to accept.  Something so basic as being able to read/write at the sametime should be a top priority in the next software update.

[lovingHDTV]

I see the same thing also.

 

I also see that for the first 1min or so it flat out flies on the transfer and the peaks and vallies do not exist.  After a short time, then I get the peaks and vallies for the duration.

 

Anyone else see this change?

 

 

[paqmaster]

I see the same thing also.

 

I also see that for the first 1min or so it flat out flies on the transfer and the peaks and vallies do not exist.  After a short time, then I get the peaks and vallies for the duration.

 

Anyone else see this change?

 

 

 

Actually, I did some more detailed file transfer testing and that's exactly what I see.  I guess it's filling up the cache memory during the first minute or so on my Unraid server (1 GB RAM).  I've seen transfer rate as high as 50MB/s during this time on my GigE network.

 

The interval I see after the initial burst is random.  The peaks and vallies have different duration for me.

 

 

[JM2005]

I too have noticed this as well.