Support for Apple Xsan server solutions

HELIOS fully supports the Apple Xsan file system with all HELIOS server products.

HELIOS server solutions bring many reliability and performance benefits to Xsan. HELIOS EtherShare server-based find file will find any file on an Xsan volume within seconds. This is more than 1000 times faster than the Apple AFP Server using the same Xsan volume. The HELIOS built-in server fail safety ensures that if one or more processes fail, all other running users are not affected. The HELIOS advanced printing system brings high-end print server features and reliability, while HELIOS adds remote server administration for Windows, Mac OS X and UNIX / Linux users. The HELIOS UNIX desktop utilities (mv, rm, cp, ls,...) properly handle file copies, etc., directly on the server by preserving the Macintosh specific resource and Windows file streams information, preventing data loss and assuring full cross-platform compatibility. The HELIOS File Server bundle enhances Xsan systems, and brings fully integrated cross-platform networking to Mac, Windows, and Web users.


AFP Xsan

Finder find file

270000 files (20 GB)

1 sec.

1800 sec. = 30 min.

(Server one CPU 100% busy)

Mac OS X AFP clients

All tests passed

Server find file failed

Saving existing file failed (Can lead to data loss!)

Supported Xsan configuration:

  • Each Xserve serves a different HELIOS volume

Unsupported Xsan configuration:

  • Multiple Xserve serve the same HELIOS volume
  • This configuration is only suitable for applications that are specifically written to be compatible (e.g. some video programs). In general, this setup is not appropriate for typical file server usage
  • File and record locking; concurrent access damages files
  • Tests with UNIX tools and QuarkXPress revealed that a file may show different content when viewed from different servers
  • We learned from Apple that every front end Xserve is doing its own read and write disk caching unless an application calls a special file sync for each write and read call. This means you cannot share the same data/folders with multiple Xserves because each Xserve may see data from its local cache and not the data the second or third Xserve has just written.

There is a way to flush data but we do not have control over the applications (like InDesign, QuarkXPress, Photoshop, web servers, databases, file and print servers, asset management). For some custom applications like an Xsan based movie editing application which is directly working as an Xsan node and using special Xsan APIs to flush the data, they may share the same files. For server solutions each Xserve must share an exclusive folder per Xserve only, otherwise customers will run into serious problems such as damaged files or seeing a different file content depending upon which Xserve accesses the files.

Technical note:


Xtar does not work;
Xsan uses Apple Double file.


Xsan is case-sensitive like UFS file systems, e.g. Linux, Solaris.

UTF-8 file names

HFS and Xsan store umlauts and special characters with a different encoding. Use HELIOS file services only to ensure consistent file names.

Manage files and folders always remotely via AFP / SMB servers by HELIOS.

HELIOS UNIX utilities

"dt cp", "dt rm" will handle files directly on the server.

Finder find file

Apple AFP / Xsan file systems have no Desktop database which results in long find sequences.

HELIOS has its own Desktop database so the server find file feature is fully supported by HELIOS server solutions. This can be tested with the HELIOS File System Test.

Quota support

Free space is not shown in Finder but Quota limits are enforced.

AFP Exchange File support

(Saving existing file failure can lead to data loss)

AFP and HFS have a file exchange feature. This is needed to save new versions of existing files while preserving the file ID (Alias reference). This is not supported by Xsan.

HELIOS has its own file exchange system so EtherShare does support file exchange!

This can be tested with the HELIOS File System Test.

Tested configuration

All HELIOS 4th generation and upcoming server products have been tested successfully.