Shouldn't This Be Faster ?

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aselby

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So this is the local speed test ... which seems ok to me

I have 4 2 TB 7200 RPM drives with 8 GB of ran and a dual core 3.08 intel chip

[root@freenas] ~# dd if=/dev/zero of=/mnt/Storage/tmp.dat bs=2048k count=50k
51200+0 records in
51200+0 records out
107374182400 bytes transferred in 429.974114 secs (249722434 bytes/sec)
[root@freenas] ~# dd if=/mnt/Storage/tmp.dat of=/dev/null bs=2048K count=50k
51200+0 records in
51200+0 records out
107374182400 bytes transferred in 285.977020 secs (375464373 bytes/sec)


This issue is from windows over iscsi on a gigabit connection I'm getting about 80 MB/s shouldn't that be closer to 125 MB/s ??

Thanks
 

louisk

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Do you have any more information than this? I'm assuming you're using gig-e.

Do you have confirmation that the network will do 125MB/s?
 

aselby

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I'm using a gigabit ethernet (procurve 2810-48g with jumbo packets turned on ) I've turned jumbo packets on my 2k8 box and set the mtu on freenas to 9018

and I have other machines that can talk faster (about 125 MB over samba)

I'm connecting over iscsi by the way if that means anything
 

louisk

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I can't see that jumbo frames would have anything to do with it. Modern switches should not have issues using standard 1500b frames.
While I haven't tried iSCSI on FreeNAS, I've used it on both EqualLogic (now Dell) and EMC and not seen as high a throughput as you can get with lower-overhead protocols such as cifs.
 

aselby

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So your saying that speed is about right and really the only thing to do if I want to go faster is get some teaming NICs on my FreeNAS server and the two servers that I want to access the iscsi share from ?
 

louisk

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The speed doesn't seem too far out.

Ling aggregation could be useful if you have more than one machine accessing the FreeNAS at the same time, however if you want faster throughput I'd suggest interconnects between your hosts. Of course, you will also want to consider additional disks to keep up with the increased speed of the new interconnects.
 

aselby

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Thanks

What do you mean by Interconnects ?

If I put in Teamed NICs on the machine that is accessing the iscsi share and FreeNas wouldn't that increase the machine for that single machine and since my local speed seems to be around 300 MB/s then even if the teamed NICs double what I get now wouldn't that only be 160 MB (still well below the 300 MB/s) ?
 

louisk

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There is no "teaming" that I'm aware of. The only such option I can think of would be etherchannel, and that requires a switch with the same capabilities. All other forms of link aggregation are LACP compliant.

interconnects are the means by which you are connecting your hosts. examples include ethernet, fiber channel, and infiniband.
 

louisk

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You can add as many of those as your machine has slots for. You should read up on how LACP and Etherchannel work. Those are the only methods of link aggregation that FreeNAS supports. The way that LACP works is that you will only get additional bandwidth when you add unique pairs of hosts. You would require etherchannel to get additional bandwidth between a single pair of hosts. Either way, you will require a switch which supports the capabilities you want to use.
 
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