Xsan5, Better and Better

abstractrude's picture

The macOS Sierra Public Beta is now live, so almost everyone can dig into the latest version of Xsan with the Server Beta.

Since 10.7 was released Apple has continued their work with Xsan, delivering new versions every year. After spending a few days with Xsan 5, I can tell you things are truly better than ever. New permission features, faster metadata operations and of course the same free licensing model we have enjoyed for years.

Xsan was a complicated piece of software with Xsan Admin as the primary management interface. I can’t tell you how many times I saw a 2.2 or earlier Xsan with a horribly broken Xsan Admin. Computers offline or not listed properly, metadata controllers out of sync, etc. Xsan Admin was the complicated part of Xsan.

Apple did something smart with Xsan 4, they moved to a passive administration model. Start, stop the volume in Server Admin and mount clients with a profile. Everything else is behind the scenes. For some power users this is unacceptable, that’s why the command line interfaces exist. Those interfaces are all still available in Xsan5. Volume creation is still simple, there are no advanced settings to configure such as block size and stripe breadth.

There is a new feature that will catch everyones eye though, ignore permissions. Yes the same check box you have had on external drives for years now comes to the volume creation portion of Xsan admin. ACLS are ignored and users can simply read and write, no matter local status of directory based users. This is a killer feature for small SANS.

Questions and Answers from WWDC 2016:
While I was at WWDC I asked a few questions to an anonymous engineer, here we're the responses.

Question: Will Xsan 5 see the same metadata performance improvements that Stornext 5 sees?

Answer: Our experience is that it will. The largest improvement StorNext 5 gets is from the fact it is simply more efficient at storing metadata information. For heavily-fragmented files, it is about ten times more efficient, resulting in one tenth the disk I/O and correspondingly improved performance. Xsan 5 sees that same benefit.

Question:Possibly the most interesting new thing I see in Xsan5 is the ignore permissions feature during the volume creation. Does this mean that smaller SANS don't need directory based user/permissions schemes anymore?

Answer: Yes, smaller SANs no longer need directory based permissions. ACLs on volumes with ignore permissions set will be ignored.