Slow speed with Open-E and vSphere ESXi 4

[d2globalinc]

There is a pdf I beleive on open-e's website that has the iops / startup script edits of /etc/rc.local too..

I have a question tho... Where did you come up with this:

MaxBurstLength=1047552

I've seen only one post on the net with this setting and its in these forums.. Everywhere else I read that this number "should be set to multiples of PAGE_SIZE" - which is 4kB (4096).
See FAQ Here: http://www.forum.open-e.com/faq.php?...q=headerdigest


I just really want to make sure this number has some meaning rather than being something just tossed out there or even a typo.

I'm also guessing that you set FirstBurstLength to 1/2 the value of MaxBurstLength.. Also what is the reasoning for this? I'm just trying to see why these settings are what they are.

Thanks!

- D2G

[d2globalinc]

Ok - My conversion may be wrong - should the PAGE size be 512 instead of 4096? - Then the math would work -

[hugor99]

TBH, this is the first time I've ever played around with TCP settings other than in Windows.

I got that number from the forum suggestion as you said. I had the same problem as the poster, if I used the 16XXXXX value, it knocked out my connection to my target, so I used the suggested value.

http://www.forum.open-e.com/showthre...hlight=1047552

[hugor99]

Update: I've done more iometer testing with RAID 10 arrays (using 6 intel x-25M SSDs) using 512k, 256k and 128k stripe sizes. The best results I got were at 128K stripe size.

In IOMeter, I got +200 MB/s transfer speeds for 16k and 32k both random and sequential. I used 8 workers and 64 oustanding ops.

I pretty much always got terrible results the lower I go, is that normal? Like 6MB/s writing (both random and sequential) at 512b.

Everything with the VMs seems pretty fast now, I can copy a large file from one folder to another at about 35MB/s, but any time I try to clone a VM it is incredibly slow, like 1MB/s. I haven't had the patience to let it complete yet. Anyone have any suggestions?

[hugor99]

Update:
I'm getting great speeds with IOMeter right now with the following settings:
MaxRecvDataSegmentLength 65536
MaxBurstLength 524288
MaxXmitDataSegmentLength 65536
FirstBurstLength 262144
MaxOutstandingR2T 8
InitialR2T No
ImmediateData Yes

My VMWare paths are configured for roundrobin, IOPS of 1.

The speeds I'm getting are:
Size Seq Write Seq Read Seq 50% Rnd Wr Rnd Read
512b 6.9 35 16.8 15 35
4K 99 174 147 108 174
16k 222 223 300 222 222
32K 224 208 307 222 210

So I'm totally happy with that so far, but still I max out at 1.5MB/s read and 1.5MB/s write when cloning a machine. I've checked the switches for collisions or something, and can't find anything. And the 50/50 speeds look nice and fast, so I have no idea what is going on there.

[hugor99]

Fixed the table so it was a bit more readable:
Size______Seq Write_Seq Read_Seq 50%__Rnd Wr___Rnd Read
512b_____6.9_______35_______16.8______15_______35
4K_______99_______174______147_______108______174
16k______222______223______300_______222______222
32K______224______208______307_______222______210