[MacTUG] Mac mini Server

[Steve Hellyer]

Depends on a number of factors. Network speed of clients and server and congestion. How disk were setup. RAID 0 or 1 or not at all. Total RAM.

I have seen Mac Mini used successfully for classroom imaging.  30 Computers if you using multicasting to actually deliver images.  Unicasting it likely not a good idea unless your striping the internal drives.  They are only 5400 RPM.
If you're striping there is no redundancy so if one of the drive fails you have lost all data on server and have to rebuild from (hopefully) backups.

This server makes a great home server, or web server where connection come in and leave quickly. Caching can be in Appache.
Netboot is much more I/O intensive and even more so if delivering large deployment images.

Speed of Netrestore vs Deploystudio is same. All use Apple Built in Netboot (NFS) to clinet and then use APF or HTTP to deliver images. AFP is slight faster. It not a speed thing it ability to properly make master and Bombich Netrestore doesn't.

Some things to consider... 
In my testing a single 7200 RPM drive copying over network can consume about 400Mbps. Two 7200 drives stripped can saturate a 1 Gbps network. If you're on a 100Mb network then you bottleneck is the network.  If you on a 1 Gbps network then disk I/O at server can play a factor. 

It all very dependant on your deployment strategy.  Unicast allows you to image individual computers on demand and you can monitor each individual client.  It uses TCP and provide guaranteed delivery.  It is however much more network and disk intensive. The netboot part is alway Unicast after that you can unicast or multicast images.

Multicast is less I/O as it one stream all client are collecting. It is however very tricky to find sweet spot for speed of delivery as different computers. Speed of delivery is slower and you get gains in time by imaging a large number of computer at one. Multicast is VERY prone to network congestion.  If you on a active network you may find alot of client fail to get image which mean you have to re-image then and you lose time gains.

Keep in mind that with Apple tools and DeployStudio the server performs final compression on image if you have selected compressed image. I am hoping you do as this speed delivery and reduce I/O on disk and network.
Mac Mini server will compress your final GM image MUCH slower than XEON (Gainstown) on the Xserve.
If you like me you're creating images, testing, fixing and re-creating image to perfect final image this can be a real pain waiting for final compression on a 20GB or so image.

The scenario when a Mac Mini might be a good fit for netbooting might be as follows...

I have a classroom of 30 Macs. Each semester we prepare and updated image with latest OS and software. We don't need to bind to a directory server.  Have Mac Mini server on a cart I roll into classroom and I disconnect classroom up stream network so no traffic in on it.  I then plug in Mac Mini server and netboot all the classroom computer and simultaneously image all the computer using Multicast.  When complete I disconnect Mac Mini and reconnect upstream connection to classroom on the ethernet switch.

All other scenario I suggest to you an entry level XServe with 8 or More GB RAM and 3 Fast drives (SAS 15000 RPM or SATA 7200) in a RAID 5 config. The time you save will make up the cost different many times over the life of the server.

I actually use an old Fibre Channel Xserve RAID as image storage as this is even faster. Keep in mind for my needs people are imaging all the time as they prepare new computers daily and I have server connected to two 1 Gbps network. An internal production network and a private LAN for just imaging.  At times I see both 1 GB interfaces on the server fully saturated. CPU hit is about 20% but disk I/O is very intensive.  The old, I mean 2004 old, Xserve RAID with 16 x 180 ATA-100 drives in RAID 50 is kept quite busy.

Final point is Mac Mini server can grow much. You can't add cards, limited externally to USB and Firewire 800/400 storage.
You relying on 2.5 inch internal noteboot type drives rather than large and typically faster 3.5 drives. Don't get me wrong it's a great computer and I now use one for my server demo but then that is pretty light duty.

Hope this helps.

Steve

On 2010-01-05, at 9:31 AM, Dani Roloson wrote:

> Any estimates on how many netboot clients this puppy could handle?
> 
> Dani
> MFCF
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