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slow disk read/write problem over network.

Posted on 2012-12-29
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Last Modified: 2013-01-07
I have configured 4 SAS 15k RPM disks in RAID 1+0.
I ran read/write test using two simple benchmarket softwares downloaded from download.com. It shows that read/write to the drive locally shows;
read 600MB/s
write 580MB/s

Then I ran the same tests over network from multiple workstations, it shows;
read  6MB/s ~ 18MB/s
write 11MB/s ~ 40MB/s

I think there's some delay in network which causes the difference. Both ends of server and workstations have 1Gbps link. So, in theoretically, I expected somewhere between 50MB/s ~ 100MB/s for read/write. But it's way too lower.

What can it cause this delay and where should I start troubleshooting? Can it be some nic configurations on both end?

Both ends have auto negotiation and switch as well.
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Question by:crcsupport
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by:Gerald Connolly
Gerald Connolly earned 150 total points
ID: 38730491
What OS are you using? Is this an iSCSI setup or just a mapped drive?

A 1Gbps link is nominally 100MB/s but 50MB/s is a more realistic max due to the nature of Ethernet and the overhead of the protocol
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by:Teeshirt
ID: 38730686
Depends on which access layer switches you are using!
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by:wrwiii12
ID: 38730907
This would seem normal to me.  Your server drives are going to R/W a lot faster because they are designed to, whereas the desktop drives are going to be a slower format.  You gave the specs for the server drives which are high end drives but not the specs on the desktop drives.

I am guessing they will be PATA or SATA 5400 or 7200 RPM drives which will not be anywhere close to the 15k SAS drives.

Use a program called flash bench to test the drive speeds as it will not depend on your internet connection/network and that will give you the true speed results of your drives.
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by:Teeshirt
Teeshirt earned 150 total points
ID: 38730922
"as it will not depend on your internet connection/network and that will give you the true speed results of your drives. "

i strongly disagree.. I work in the Textile industry, we have designers uploading big files to shared folders at FULL network capacity.
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by:crcsupport
ID: 38730958
OS is windows 2012 and workstations are windows xp. Correct, workstations have sata 7000RPM.

Is there any benchmark using buffer to test so that workstations' disk speed doesn't affect the speed test? I like to troubleshoot where exactly the problem is.
I also have SSD notebook, will bring in and do the same test if it does anything different.
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Author Comment

by:crcsupport
ID: 38730977
switch is dell powerconnect 5448
workstations have various nic, intel pro 1000, etc in PCI or onboard., SATAI, SATAII...
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Expert Comment

by:wrwiii12
ID: 38730978
There are many variables between everyones systems and networks.  You can have the fastest drives in the world in your computer but if your hardware bus speeds in the computer don't let it transfer at that rate then it wont utilize the full drive capacity.

I would suggest you download flash bench, which is a tool that runs directly on the system and tests file tranfer rates of both large and small files.  You don' t have to install it as it runs in memory and it is free.  This will give you the fastest rates that the drive/system will even allow.

Ok it looks like their site is down.  If you want to try this let me know and I will put it out there for you to download.
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by:crcsupport
ID: 38731700
wrwiii12, can you put it somewhere to download?
thanks
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wrwiii12 earned 200 total points
ID: 38731720
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