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Can iSCSI compete against Fibre channel SAN connectivity? |
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Written by Richard Thompson,
Wednesday, 11 April 2007
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Is iSCSI able to hold its own against Fibre channel SANs?
The answer is simple, I don't know. Each technology has its pro's and cons and over the past few months a lot of companies have been doing research and investing in such technologies. Virtual infrastructure is becoming a large part of our industry and in order to accomodate this SANs are becoming a larger and larger part as well.
One of the first disadvantages of iSCSI that everyone comments about is performance. Because iSCSI makes use of your regular ethernet network equipment it has throughputs of 1GBps. When you compare this to the 4GBps you can get from Fibre you start to get concerned. Fear not. eWeek labs did a comparison between iSCSI and Fibre interfaces to their AX100 SAN solution which was used for their test Exhange database and found that performance differences between the two was negligable. This is great news for iSCSI especially when you consider that 10GB ethernet switches are now available.
The next major disadvantage is that you need specific iSCSI initiator software installed on your Servers. This used to be a problem for people using certain operating systems. That said, Most major operating systems now include iSCSI initiator software. Sometimes not all built in but all are freely available for download on the companies websites. The only exception to the rule is Mac OSx.
iSCSI does consume server processor cycles however storage managers have produced a workaround to this. The solution is to install TCP Offload Engine (TOE) cards in your servers. So when pricing a solution you need to take this into account.
So far everything I have mentioned have been indicating as to why you should not go with iSCSI, now lets look at the positive points.
For a start iSCSI is considerably cheaper. In eWeeks survey the initial setup was US$4000 cheaper to setup and once you have the initial infrastucture in place cost per server is significantly lower to add additional servers to an iSCSI based solution.
The reason for this is because the components are more readily available and you can use existing LAN infrastructure instead of needing to activate another port on the fabric switch, assigning LUN's, etc!
Support costs are also significantly lower because you don't need to employ storage expert and most IT Managers or Technicians are familiar with Ethernet and IP Networking making it possible for them to install and configure the solution themselves, albeit with a few minutes reading.
In short, iSCSI may not be 100% ready to take on some of the larger more sophisticated Fibre Channel solutions, but they are definately on the way up particularly for small to medium size companies and there is a bright future in the market for iSCSI. Businesses who choose to implement iSCSI should keep the following in mind, spend a little extra cash to buy good quality network equipment. Doing this will help ensure optimum performance and where possible use seperate network infrstructure for your iSCSI network. Doing so will prevent this from competing with regular network traffic!
Sources:
http://www.eweek.com/article2/0,1895,1925404,00.asp
http://www.eweek.com/article2/0,1895,1926088,00.asp |
