Tag Archives: Storage


Mac Servers – What I’m Doing

Hopefully this should be the last post about Macs for the time being! I don’t know why I’ve written so many recently, I guess it’s just because the bloody things take up so much of my time at work. Don’t get me wrong, I like Macs a lot for my own purposes. I own two, my girlfriend has one, we both have iPhones, I have an Apple TV and an AirPort Extreme router. I even subscribed to MobileMe when you had to pay for it. It’s just that professionally, they’re a pain in the arse and if you really want I’ll put that on a certificate for you to put on your wall.

Anyway, my last post was originally supposed to be about the Apple server solution that we’re using at work. However, it kind of turned into a rant about how Apple has abandoned the server market. I stand by the post entirely but I thought I’d try to write the post I was originally intending to write!

A few months ago I got a call from the technician in the Media Studies department who looks after their Macs. As far as he could see, the Mac had stopped working entirely and he was getting into a bit of a panic about it (The Mac was actually fine, it had just buggered up its own disk permissions preventing anything from launching). The reason he was panicking was because he thought that all of the student work stored on it had been lost. These Macs are used for editing video using Final Cut Pro; because of the demands that video editing puts on a computer’s storage subsystem, it is totally impractical to edit video over a network on one computer let alone 40 at once so therefore the student has to store any work that he or she does on the Mac itself. If that Mac fails then the user kisses goodbye to all of the work done that year. That wasn’t acceptable but he and the college had put up with it up until that point. He wanted to know if there was a way to back them up so that if one does go kaboom, we have a way of recovering their work.

This turned into a fairly interesting project as I had to investigate viable solutions to achieve this. I came up with four:

  1. Backing the Macs up using an external hard drive and Time Machine
  2. Backing the Macs up using a server running OS X Server and Time Machine
  3. Backing the Macs up using a server from another manufacturer using some other piece of backup software
  4. Backing the Macs up to a cloud provider

First of all, I investigated and completely discounted the cloud solution. We would need in the order of 20TB of space and a huge amount of bandwidth from the cloud provider for the backups to work. The Macs would need to be left on at night as there would be no way we’d be able to back then up during the day and maintain normal internet operations. It all ended up costing too much money, if we had gone for a cloud solution we would have spent as much money in six months as it would have cost for a fairly meaty server.

There was also quite some thought put into using USB disks and Time Machine to back them up. This certainly would have worked, it would have been nice and simple and relatively cheap. Unfortunately there were some big downsides too. Securing them would have been almost impossible, it would be far too easy for someone to disconnect one and walk off with it. If we wanted any decent kind of speed and capacity on them, we probably would have had to of used enclosures with 3.5″ drives in them which would have meant another power supply to plug in. Finally, I couldn’t see a way to stop students just using them as an additional space to store their stuff on completely negating the point of them in the first place.

So that left having a network storage for the Macs to store their backups on. First of all, I looked at Dell (Other server vendors are available) to see how much a suitable server would cost. Dell’s range of servers with lots of 3.5″ drives is frustratingly small but eventually I managed to spec a T620 with 2x1TB and 8x4TB drives with a quad core CPU and 16GB RAM, a half decent RAID controller and a three year warranty for about £7500 retail. Add on top the cost of a suitable backup daemon and it would cost somewhere in the region of £9000-£9500. Truth be told, that probably would have been my preferred option but a couple of things kept me from recommending it. First of all, £9500 is a lot of money! Secondly, although Apple have been deprecating AFP and promoting SMB v2/v3 with Mavericks and Yosemite, Apple’s implementations of SMB have not been the best since they started migrating away from SAMBA. AFP generally is still the fastest and most reliable networking protocol that a Mac can use. With this in mind, I decided to have a look at what we could get from Apple.

The only Server in Apple’s range at the time was the Mac Mini Server. This had 8GB of RAM installed, a quad core i7 CPU at roughly 2.6GHz and 2x1TB hard disks. Obviously this would be pretty useless as a backup server on its own but that Thunderbolt port made for some interesting possibilities.

At first, I looked at a Sonnet enclosure which put the Mac into a 1U mount and had a Thunderbolt to PCI Express bridge. I thought that I could put a PCIe RAID controller in there and attach that to some kind of external SAS JBOD array and then daisychain a Thunderbolt 10Gbe ethernet card from that. I’m sure it would have worked but it would have been incredibly messy.

Nevertheless, it was going to be my suggested Apple solution until I saw an advert on a website somewhere which lead me to HighPoint’s website. I remembered HighPoint from days of old when they sold dodgy software RAID controllers on Abit and Gigabyte motherboards. A Thunderbolt storage enclosure that they promote on their site intrigued me. It was a 24 disk enclosure with a Thunderbolt to PCIe bridge with three PCIe slots in it and, crucially, a bay in the back for a Mac Mini to be mounted. Perfect! One box, no daisy chaining, no mess.

Googling the part code lead me to a local reseller called Span where I found out that what HighPoint were selling was in fact a rebadged NetStor box. This made me happy as I didn’t want to be dealing with esoteric HighPoint driver issues should I buy one. Netstor in turn recommended an Areca ARC-1882ix-24 RAID controller to drive the disks in the array and an ATTO Fastframe NS12 10Gbe SFP+ network card to connect it to the core network. Both of these brands are reasonably well known and well supported on the Mac. We also put in 8x4TB Western Digital Reds into the enclosure. I knew that the Reds probably weren’t the best solution for this but considering how much more per drive the Blues and the Blacks cost, we decided to take the risk. The cost of this bundle including a Mac Mini Server was quoted at less than £5000. Since OS X Server has a facility to allow Time Machine on client Macs to back up to it, there would have been no additional cost for a backup agent.

Considering how squeezed for money the public sector is at the moment, the Mac Mini Server plus Thunderbolt array was the chosen solution. We placed the order with Span for the storage and networking components and an order for a Mac Mini Server from our favourite Apple resellers, Toucan.

Putting it all together was trivial, it was just like assembling a PC. Screw the hard drives into their sledges, put the cards in the slots, put the Mac Mini into the mount at the back and that’s it. After I connected the array to the Mac, I had to install the kexts for the RAID controller and the NIC and in no time at all, we had a working backup server sitting on our network. In terms of CPU and memory performance it knocked the spots off our 2010 Xserve which surprised me a bit. We created a RAID 6 array giving us 24TB of usable storage or 22.35TiB if you want to use the modern terminology. The RAID array benchmarked at about 800MB/sec read and 680MB/sec write which is more than adequate for backups. Network performance was also considerably better than using the on-board NIC too. Not as good as having a 10Gbe card in its own PCIe slot but you can’t have everything. The array is quite intelligent in that it powers on and off with the Mac Mini; you don’t have to remember to power the array up before the Mac like you have to with external SAS arrays.

I know that it’s not an ideal solution. There is a part of me which finds the whole idea of using a Mac Mini as a server rather abhorrent. At the same time, it was the best value solution and the hardware works very well. The only thing that I have reservations about is Time Machine. It seems to work OK-ish so far but I’m not sure how reliable it will be in the long term. However I’m going to see how it goes.

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