This is awesome. Honestly the XSAN controllers needing their own Xserve allways seemed a little over-kill to me.
It might seem like overkill, until you start running an Xsan environment. Then you realise why you need all the performance and enterprise features the Xserve has.
But is it a direct replacement for the XServe? Since when is a SAN a server? Maybe I don't understand what a SAN is, but...
So it must be a hybrid box then to be used AS a server OR a SAN box...
Still wish I had the money to get one while I still can get a new one.
Still not understanding it, are we? (This is aimed at nobody specifically, just most people chiming in to this thread!)
A SAN is a network designed for high performance storage access. These days you can easily roll out a SAN solution that allows each Mac Pro connected read and write at over 800MB/s - suitable for streaming anything up to uncompressed 4K. To
each workstation,
simultaneously.
The SAN hardware works by separating the data and metadata (the 'pointers' telling the filesystem where each file is, how big it is, etc), usually between distinct storage pools. While you can pool everything together, it's a
Very Bad Idea. With Xserve RAID (the old Apple solution) they advised putting meta data on the first two disks in your storage hardware. While that's fine if you're not hammering storage, nowadays you
have to have it on a dedicated chassis if you want to get anywhere near the performance these things can offer.
The closer the metadata is to the MDC (metadata controller), the faster the SAN can perform (i.e. respond to requests) - hence the recent Active Storage innovation
InnerPool, which stores said metadata on SSDs based on the MDCs fibre card itself.
SANs are fickle creatures. They require lots of attention and careful maintenance to ensure they run efficiently. One of the joys of Xsan is the fact it's not too many steps away from install the software and go - leaving you to actually administer the damn thing, which can take a considerable amount of time.
ActiveSAN is designed to function as a suitable MDC replacement for Xserve based MDCs. While I'm fully capable of StorNext admin, I'm not about to go and set it up because it takes more effort. This isn't 'who's got the biggest geek wang', it's all about efficient working. If I can buy something that I can set up and ignore, that's brilliant, something my clients would agree with.
Here's an example of a standard SAN setup in the media world (where this product is aimed):
8x 32TB RAID Chassis (each with dual redundant controllers)
Qlogic fibre switches (populated with four connections for each RAID and two for each workstation & MDC)
Ethernet switches (providing dedicated ethernet network for metadata transactions to each workstation & MDC)
2x MDCs (for redundancy)
Metadata: 1x RAID chassis with mirrored SAS drives - or - InnerPool
There we're talking 256TB of raw storage. Using RAID5, that's ± 230TB or so counting for parity data (the stuff that makes a RAID5 volume recoverable on-the-fly). You'd include hot spares too so the pools (2 per RAID) would reduce to something around the 200TB mark. Consider the fact that you can't fill a SAN more than 50% before performance takes a hit, you're talking 100TB usable.
If you're in a high performance environment dealing with editing and VFX, you could be in the millions of metadata transactions a second, meaning two
beefy servers are required for serving out that data.
High availability is an absolute steadfast requirement. If a PSU blows on a Mac Pro MDC, you could be stuffed (you don't require two MDCs but it's best to have them). Anything happens, you want redundancy for as much as is technically possible.
TL;DR: A SAN != a Server. But it needs two to function properly.
Thanks for all the guys in this thread who work with servers kindly answering the questions the rest of us have regarding server hardware/software. This is not always the case with many of these threads and it's good to see.
I have another question to add. Is it possible for large server setups to be replaced by one or just a few mac pros/minis runnino osx server with the storage based in the cloud (or Apple's data centre) thus removing the need to large amounts of hot swappable power supplies/harddrives?
I was just thinking this because Apple tend to steer in the direction of the latest trends before anyone else does and thought maybe they are offering a fee based osx storage as a use for their huge data centre...
sorry if this is waaay off the mark guys
thanks
Quite a few post houses I know are moving to Mac minis for their main server services - user/group management, DNS, DHCP and the suchlike. You gain redundancy by adding a boatload of them with primary, secondary and tertiary services scattered around each.
However, for Xsan networks, "the cloud" is not a replacement, and is never likely to be. Considering the above figures, you'd never get anywhere near the performance required. In other industries maybe it would be a replacement - except for the fact that most people don't like their data going 'out of house', for security reasons.