DroboPro: Part 2

I wrote a couple weeks ago about a cool new offering from Data Robotics here, called the DroboPro. Well, here we are a couple of weeks later and i thought i would share my findings with this cool new tech, now that we have it in the field.

I had previously mentioned that Drobo worked on a technology called iSCSI where as the more expensive solutions currently available will typically use Fiber Channel. I have to admit that installing the DroboPro at a large client had me worried with regard to data throughput. I was unsure whether a device like this could match up to an XServe RAID when dealing with large amounts of data. Apple used to reccomend this product exclusively for server deployments and has since adopter the newer Promise Tech RAID solution. These ranged in price from $7,000 dollars and up depending on your storage configuration. This piece of hardware used Fiber Channel as its only means of data transfer which adds significantly to the cost of ownership.

Best Macs has always been focused on delivering the best service and products to the client. Having said that, we have also always been cognizant of the financial burden many of the more robust technologies will place on a business, and a 7k entry fee is a pretty big pill to swallow for the majority of businesses. So here comes DroboPro; a device which starts at $1299 with no additional software required to operate, and no additional hardware cards to purchase and take up valuable slots in your server.

You may be asking yourself: “surely if it is that much cheaper then it will be much slower than that more expensive stuff.” Not necessarily the case. As a for instance: A fiber channel card will typically have a theoretical bandwidth limit of 4GB/s where as DroboPro’s iSCSI uses gigabit (Gb/s) ethernet for transferring data. Clearly Fiber channel has the upper-hand in raw speed, of this there is no doubt. However when under real world use, we have found that at a client who uses both a DroboPro and an XServe RAID the speed is often either comparable or favoring the Drobo.

**It should be noted that these setups are mainly intended to be fault tolerant. Meaning the ability for a storage pool to lose one or more drives without any data loss. We feel that data redundancy is typically more important than speed. But we never mind if we get more speed while being data secure

So why is this? Why would a much less expensive device be faster than an XServe RAID?

4 Things:

• SATA Drives.
• Fiber Card Limitations
• Beyond RAID Technology
• Fiber Channel Overhead

The drives that the DroboPro uses are based on the newer SATA technology which allows for a maximum data transfer of 1.5GB/s. This allows for more data to be pushed back and forth out of each drive. Single drive speeds can now achieve speeds faster than multiple drives working together of the older IDE tech.

Until recently the Fiber channel cards worked exclusively over PCI-X bus ports. This bus allows for a theoretical Max of 1Gb/s bandwidth. If you have a newer card that works over PCI-e then you will get the full 4GB/s max but for any of you still rocking older XServes based on PPC hardware you are stuck with the slower version.

Data Robotics’ technology called “Beyond RAID” is like having all of the different RAID levels at your finger-tips without having to worry about which to choose at a specific time. Since Beyond RAID is block level it can change its RAID algorithm at any time from block to block. The advantages here are many but with regard to speed you get the benefit of striping the data allowing multiple drives to be written to simultaneously while maintaining parity.

When you transfer a file from one place to another on a computer you are actually transmitting more than merely the data itself. Other data accompanies your files that describe what kind of file it is, how it should be transferred, how to decode the file, etc. All of these different pieces of data are referred to as the overhead for the specific protocol. Fiber Channel typically has little overhead when transferring data packets, howerver in order to read that data it takes a significant amount more computational horsepower. In real world situations this means that an additional card would be required to leverage the load of the Fiber channel traffic. iSCSI on the other-hand uses a standard Gigabit ethernet port to transfer its data over a TCP/IP protocol. What this ends up meaning is less work for your computer and a lower cost to you.

So why wouldn’t you buy a Drobo for your business? So far this list isn’t too large, but it is important. I would only recommend the DroboPro to a business who utilizes leopard server and a PowerMac/XServe Dual G5 or newer machine. The reason is that typically you will want to use this device with its iSCSI port which will require a Gb ethernet port and all of these have two, enabling you to have this and your typical internet traffic on the same box. In addition i would tell you that the iSCSI protocol places an additional burden on the processors of anyone running PPC hardware. Intel had made their processors capable of easily handling the Drobo and iSCSI and users will see little increase in processor usage while running a DroboPro.

The unit is easy to use but can take some setup. More advanced implementations can be a bit tricky but as always Best Macs can and will assist you. If you are a small business with 1-10 users a DroboPro may either be out of your budget or may just simply be overkill. If you are a business who has more than 100 users a DroboPro may not be quick enough to handle all of your needs.

If you have any questions about the Drobo or DroboPro and whether they fit into your companies data strategy let us know and we will be happy to come out and assess your needs. Stay tuned for more from the Best Macs team about the Drobo and Drobo Pro!

**1 GB = 1.024 Gb or 1024 MB: This difference is noted by an upper case B or lower case b where B represents Byte and b represents bit.

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