Jumbo frames and drive speed

[foolinator]

I was wondering where's my bottleneck for speed. When copying a large file (1 gb) it takes about three minutes. I've read about people getting 50MB/sec transfer rates. I'm calculating about 5.6MB/sec.. is this right?

So here's my system:

5 750gb barr. drives
raid 5 configuration
54K stripe size
Link aggregation on
have a jumbo frame supported switch up to 9000 size
jumbo frame size set to 8000 on thecus
jumbo frame size set to 9000 on windows
switch is hooked up to 100T router for internet access

I've tried everything so far, and I'm starting to come to the conclusion (after dumping and organizing well over 1500GB of data) that I really fubar'ed by making a stripe size so dang small - but I didn't imagine that my transfer rates would resemble that of a 100Mbps network -- I figured it would me like 20-30megs a sec.

[omega]

Hi foolinator,

what speed is the ethernet connection between your PC and your N5200? What I understand from your post it seems that you're using 100 MBit ethernet (100BaseT)

If you're using 100 Mbit ethernet the absolute maximum is about 10 MByte/sec, but I assume you already know that.

As I've posted in another thread, I'm having RAID 5 with the standard stripe size of 64 K, no link aggregation, no jumbo frames nothing special but 1 GBit on my PC, on my switch and of course on my N5200.
With this setup I get about 18 MByte/sec with the SMB/CIFS protocol and about 23 MByte/sec with NFS.

Andreas

[foolinator]

Thanks.. I suspect, even though they're all hooked up to a 1GB switch that supports jumbo frames w/gigbit speeds reported, that my 100T router is somehow poisoning the LAN. I further tested by sending files from multiple machines at the same time and there was no slowdown by the thecus, saying that somehow my LAN is fubar'ed.... Thing is, I just don't understand why - I always thought the switch was smart enough to send between machines and not first go through the router. I guess I better reread some of my networking books, because I suspect it's going through something on the router first.

Anyway, I just ordered a gigbit router. I want to throw this d**n router out the window

Thanks for the sanity check.. I'd rather have 64K stripes because I do move a lot of code between the machines.

[ondro727]

Regarding the speed - I move lot of 2K scans (12-20MB each) to/from N5200. Setup - RAID5, 5x500MB, 256kb stripe (I think, I have changed to this value last time), no link aggregation, connected through value Linksys giagbit switch. Copying this type of data from hi-speed local FC storage (>300MB/s), after some tests I have found the write speed to be appr. 25MB/s, while read speed appr. 28MB/s. I have read that write speed is usually faster, but in my case it is not Jumbo frames didn't change almost anything (didn't test it in the same setup, since switch doesn't support it - had to connect directly to the machine with FC array), maybe 1MB/s faster both w/r.
Just my few cents

P.S. Ooops, all this is while using CIFS shares. Forgot to mention it. Tried to test FTP transfers, but they were slower than CIFS (I don't know why, but I expected FTP to be quicker...).

[kevincy]

Hi ,

What firmware version ,do you have?

[foolinator]

I'm running 1.0.7

I just turned off jumbo frames on all my machines and found a vast speed increase. My switch does support JF, but I suspect my ethernet cards aren't playing well with it.

Also, I'm convinced that jumbo frames work well unless the frame sizes line up with one another 100%. I've read on here that it's ok to set the thecus to 8000 and my nic to 9000. But even though my NICs allowed for such a setting, it didn't work right.

Also: if you have jumbo frames setup on the machine, does it affect the router if it's not jumbo frame enabled? Regardless, I'm not educated enough with jumbo frames yet.

I'll repost when I'm brave enough to JF-it up again.

Foo

[sgunn]

To prevent fragmentation, frame sizes should be set to the same size for all devices on your network. It will still work if the sizes are different, but the frames will be fragmented. Try setting all your adapters/devices to use the same frame size. I'll be curious to see if that works.

-Stephen