Performance Information

File compression methods used

Delay before download starts

How many HTTP requests per second can be handled

Directory browsing performance

Conclusion

File compression methods used

There is no file compression used for AFP, SMB/CIFS, WebDAV, FTP and SSH FTP. Only Xinet WebNative and HELIOS WebShare use download compression. The following table shows the compression type and rate used by the different products.

	Application/Service		Compression		Fileset Size		Compressed Size		Saving
	AFP, SMB/CIFS, WebDAV, FTP, SSH FTP		none		141 MB		141 MB		-
	Xinet WebNative		StuffIt		141 MB		125.6 MB		10.9 %
	HELIOS WebShare		Zip (Flate)		141 MB		111.2 MB		21.1 %

The Zip (Flate) format, as used in HELIOS WebShare, has the benefit that it is already completely integrated in Windows XP or newer. Opening a Zip file is supported in the Microsoft Windows Explorer. On Mac OS 9 and OS X, Zip files are supported by the included StuffIt application. A second benefit is that Zip (Flate) compressed files are smaller than StuffIt files, resulting in faster file downloads. WebShare Zip downloads can include complete recursive (subfolders) folders. WebNative does not have this capability.

Delay before download starts

This table shows the delay after files are selected for download, until the transfer starts. The delay is due to the archive creation on the server.

	Application/Service		Fileset Size		Download Delay
	AFP, SMB/CIFS, WebDAV, FTP, SSH FTP		141 MB		< 1 sec.
	Xinet WebNative		141 MB		55 sec.		Tests issued on www.xinet.com WebNative Server, issued multiple times to ensure that no other user was using it.
	HELIOS WebShare		141 MB		< 1 sec.

HELIOS WebShare does not have any delay to compress the download archive. The compression used by WebShare, built on the HELIOS "zipstream" technology, is done on-the-fly during the download. The WebShare download stream is piped from the WebShare file server to the WebShare WebObjects Server, and down to the Browser client, all without creating temporary files.

How many HTTP requests per second can be handled

The tests were made using the curl/wget command line tool to measure the performance.

	Application		HTTP requests per sec. (more is better)
	Xinet WebNative		1-2		Using WebNative on www.xinet.com Internet packet delay (ping time) was subtracted
	HELIOS WebShare		70		On a G4/1 GHz WebShare/ WebObjects Server

This shows the server performance and indicates that the HELIOS WebShare WebObjects server outperforms any CGI web server solution.

Directory browsing performance

How many network packets are sent over the Internet to enumerate a directory from a remote Internet client.

The test was done after the server authorization by opening a volume and selecting a remote file without loading it. The server volume/share root directory contained about 34 folders. We used the Photoshop open file dialog to open one folder and select a file (without loading the file into Photoshop).

	Application/Service		Packets required
	FTP		67
	AFP (Mac OS X 10.2)		2440
	AFP (Mac OS 9.2.1)		9169
	SMB/CIFS (Windows XP)		2378
	WebDAV		12530		Test done using an Apple iDisk volume
	Xinet WebNative		970		Test done on www.xinet.com
	HELIOS WebShare		107		See details below

This clearly shows that AFP and SMB/CIFS volumes, mounted over the Internet, are very difficult to work with, due to the many network requests, which cause long delays for the clients. The Mac OS X test with 2440 packets takes less than a second in a local area network. Using a 64 Kbit network the same task would take minutes. FTP requires only 67 packets but did not include any file icons, which are displayed in all other solutions.

Using WebDAV (tested using an Apple iDisk volume), opening the volume and the first folder required about 500 packets, when selecting a file in Photoshop the machine was completely busy for minutes resulting in more than 12000 packets. This shows how inefficient the usage of a WebDAV volume with real world applications is. The test was performed using a fast 2 Mbit Internet connection.

The WebNative test was done with the "Demo INK" demo account by opening the "advertisers" folder and selecting one file for the download basket.

HELIOS WebShare is the only solution with an extremely optimized protocol implemented by the HELIOS WebObjects Server. Requiring 9 times less packets compared with Xinet WebNative means that customers will have less delays and faster responses using HELIOS WebShare.

Q: Why do Windows and Mac OS 9 & OS X use so many packets for directory browsing?
Answer: The Finder/Explorer window enumerates all files and meta data. This is done via some higher-level API calls which cause many low-level API calls which in turn results in network requests/packets. For example, the open file dialog enumerates the current directory as well as the first level of all subdirectories in order to collect directory and icon information. All this is done via thousands of network packets. Unfortunately, the OS vendors Apple and Microsoft are not optimizing this because it works fine on local machines and with today's local area networks and servers.

Please note: The following table gives an overview how many packets can be handled on different networks. This number depends on the packet size and network request type and is just an estimation.

This shows that an intelligent server solution is required for remote file access. HELIOS WebShare and Xinet WebNative use a Web based approach, which has the benefit that the HTML in the browser displays the file listing including icons, while requiring significantly fewer packets compared to direct volume access using AFP or SMB/CIFS.

Q: Why is WebDAV not recommended for remote file access?
Answer: The disadvantage of every file system based solution including AFP, SMB/CIFS and WebDAV is that, when a file system call is done via a slow network connection, no other API will will go through the file system (e.g. Disk Free status) while the old request/transfer is still ongoing. This means that the system is almost locked up during a file transfer until the transfer is completed. In application based file transfers, e.g.: FTP, the browser does not lock the file system, and the transfer will not block the OS and other applications.

Files used for the download tests
The following files have been used for the download compression tests. The same sample files from the Xinet WebNative demo site (www.xinet.com) were used for all tests. Hence, no files were optimized for the Zip download tests. The files are:

Conclusion

The two-tier server concept of HELIOS WebShare represents the fastest remote file access solution available. No other solutions come close to its server performance and security. The benefit for users is that WebShare provides very fast, easy and reliable access to the file server data.
A separate Security white paper is available.

This document is subject to change. Last updated October 10, 2003