At 11:49 PM +0200 7/28/06, Pascal Gienger wrote:
In the Apple case we need to distinguish Apple XSAN Harddisk chassis
and the XSAN software. The XSAN software seem to give you a special
filesystem for SAN issues (at least I read this on their webpage).
Let me dissect this a bit.
The Xserve RAID is Apple's RAID appliance box, two
non-redundant/failover 7-disk controllers in one box (14 disks
total), each with FC connectors connecting to (whatever). The
administrative application is a Java app. No Mac OS necessary, no
special Apple goo. A group here is using it as raw storage for
VMWare (VMFS).
Xsan is Apple's licensed implementation of ADIC's StorNext file
system. It's its own file system, *NOT* HFS+. StorNext requires a
dedicated, private Ethernet network for communicating metadata
information between the nodes and controllers. This topology is
where it falls down with lots of little files -- lots of little files
means more metadata flying between the nodes and controllers; it's
inherent to the StorNext design. On the flip side, Apple's Xsan
product is a very cheap way to implement a StorNext controller;
Apple's client licenses are (relatively) cheap as well, but ADIC will
happily sell clients for Linux/AIX/Solarix/other that all work with
Xsan.
--
Andrew Laurence
atlauren@xxxxxxx
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