Hard disk bottle neck.

Danny Do danhdo at gmail.com
Sun Sep 28 10:51:08 UTC 2008

Hi guys,


I have this problem for years but couldn't find a way to solve it.

I have a file server handling large files from 1MByte to 1GByte. 

Server Info:
FreeBSD 6.2 
Apache 2.2.9

DELL PowerEdge 1850
2GB RAM (only 184MB is active)
Gigabit Ethernet Connection

My server can output NO MORE than 60Mbps (read only). 

The bottle neck is the hard disk. If I use ONE connection to download file
from my server, the speed can go up to about 400Mbps. 

If I let visitors download using multiple connections, the server cannot
output more than 60Mbps. 

My service is similar to rapidshare/megaupload, I am wondering how they
configure their servers?

If I recall correctly, it doesn't cost much time to read the data from the
disk but it does cost a lot of time to seek for the data. Correct me if I am
wrong, if I increase the read buffer size, there would be less disk seek
(disk access). Let's say the read buffer is 64K, if I increase it to 640K,
the disk seek would reduce by 90%. Thus, more data can be read from the hard

What should I do now?

Any suggestion is appreciated!

Danny Do

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