performance issue!!

David Collier-Brown -- Customer Engineering davecb at scot.canada.sun.com
Mon Jul 12 14:43:55 GMT 1999


You wrote:
| we have an SUN E450 server with soalris 2.6 and 512mb RAM  running samba. we
| have a network and all the machines are connect through a switch. there are
| about 40 users who simultaneously use the server running samba for file
| service. 
| The set up is like this. there is an application on the server which is
| shared and all the users have mapped their drive letter to that share. this
| application when executed transfers a particular file of about 5 MB size
| from the server to the client's machine. 
| if only few users are downloading simultaneously then the down load takes
| only 2 minutes. but when about 40 users simultaneously try to download the
| file it takes about 30minutes. 


	5 megabytes / (10 megaBITs/second) =
		5000 KB / 1113 KB/S =
			4 S
			
	Assuming the load on the network is moderate, one client
	should load in something around four seconds, forty in
	around 160 seconds... or three minutes for all forty!
	
	If we also assume the application isn't doing something 
	pessimal to throttle itself, then we probably have a network,
	hub or ethercard error.  
	
	Try an ftp transfer to one of the
	clients: Samba will normally be within an order of magnitude of 
	whatever that gets!
	
	If not, start by running "sar -o `hostname`.raw 10 30" during 
	a download and mail me the file. Thta will tell us what the
	system (but not the network) is up to.  Second, get 
	a network trace, preferably from tcpdump with samba decoding.
	The Samba gurus will probably need that in order to help.
	
--dave
--

David Collier-Brown,  | Always do right. This will gratify some people
185 Ellerslie Ave.,   | and astonish the rest.        -- Mark Twain
Willowdale, Ontario   | http://java.science.yorku.ca/~davecb
Work: (905) 477-0437 Home: (416) 223-8968 Email: davecb at canada.sun.com



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