Many of the most helpful posts here have tried to touch on how important your data is, and what happens if you have downtime. My organization is going though its first, long overdue, SAN purchase. We currently have 4 2TB SATA arrays that are going to be replaced by 2 completely independent EMC CX3 SANS. We made this decision, after much pushing on the "moneymen", because downtime is not an option and the SATA arrays cannot be trusted. So, how much does an hour of downtime cost you? How big is your IT staff and can they handle management of a large Opensource file system cluster? The extra money spent on a smaller san may pay for itself a matter of hours in a failure situation.
Also, it sounds like you would like to use a SAN if the money was available. One thing I discovered about SANs is buying bigger, is not always better. You say you only need a few TB now, but hundreds later. My advice is to not be looking for a SAN than can grow to 100+TB, but to what you "reasonably" expect to be using in 2-3 years. Here is why. SANS typically come with 3 yr service warranties. At the same time, the model lifespans are also timed to be around 3 years. So, in 3 years, when your service contract is up, the model is being phased out. So, instead of renewing your service contract, you trade in and upgrade your SAN, which in three years, the smallest san will be able to do 100+ TB. I recently attended a SAN integration class for our new system where some students were from one of the US largest retailers. The students said their group buys a san, starts migrating data to the SAN (which takes 18 months), and then starts migrating data off almost immediatly after all data is migrated onto the SAN. The migration off the san, also takes 18 months.
I think you may really want to consider a small SAN as your choice, especially if you are going to buying new hardware for this sysetm.
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Many of the most helpful posts here have tried to touch on how important your data is, and what happens if you have downtime. My organization is going though its first, long overdue, SAN purchase. We currently have 4 2TB SATA arrays that are going to be replaced by 2 completely independent EMC CX3 SANS. We made this decision, after much pushing on the "moneymen", because downtime is not an option and the SATA arrays cannot be trusted.
So, how much does an hour of downtime cost you? How big is your IT staff and can they handle management of a large Opensource file system cluster? The extra money spent on a smaller san may pay for itself a matter of hours in a failure situation.
Also, it sounds like you would like to use a SAN if the money was available. One thing I discovered about SANs is buying bigger, is not always better. You say you only need a few TB now, but hundreds later. My advice is to not be looking for a SAN than can grow to 100+TB, but to what you "reasonably" expect to be using in 2-3 years. Here is why. SANS typically come with 3 yr service warranties. At the same time, the model lifespans are also timed to be around 3 years. So, in 3 years, when your service contract is up, the model is being phased out. So, instead of renewing your service contract, you trade in and upgrade your SAN, which in three years, the smallest san will be able to do 100+ TB.
I recently attended a SAN integration class for our new system where some students were from one of the US largest retailers. The students said their group buys a san, starts migrating data to the SAN (which takes 18 months), and then starts migrating data off almost immediatly after all data is migrated onto the SAN. The migration off the san, also takes 18 months.
I think you may really want to consider a small SAN as your choice, especially if you are going to buying new hardware for this sysetm.