The price difference between SATA and SAS is really very big. Of course I understood, that SAS drives have their advantages, but does this really legitimate a price difference of 100% or more? Should I really spend 1 Euro per GB?
Of course I understand, that this comes down to my usage of servers. But in may case we are not taking about high performance computing, but merely file servers and web servers etc.
I tried to find some information about this topic, and it came down to the following:
(I did not find statistics, that back up any of that)
A) SAS Drives are better in big numbers
B) The SAS Protocol is superior and allows more control and optimisation
C) The quality of the SAS Drive is also expected to be better, as those drives are produced for enterprise market (of course I am aware, that SAS does not mean, that a Drive has a better quality)
D) Drives with higher speed are available for SAS.
Now for my scenario, the prize for SAS seems insane. I need some big storage for educational videos and text-books - and for the price of SAS I might be able to buy triple or even quadruple of the storage.
Further I am applying RAID 10 and backup (both onsite and offsite) - So I think we are pretty safe...
Nevertheless there are two things, that should be considered:
Bottleneck-Situation:
I want to avoid the situation, where I buy a nice and fast server, that again has a bottleneck, which might be the drive. And we will have scenarios, where we want to use .
We have enough RAM - 64 GB per Processor - so our will completely fit into the RAM. The speed of the Hard-drives is more important for the serving of files and flash-streaming.
Reliability:
Of course, these hard-drives will run 24/7 - so do give SAS such a big PLUS in reliability? I have read different opinions - also in this platform - mostly backed up anecdotical (e.g.Warranty for SAS 5 years, for SATA 2 years - but than another person found the opposite case ;-))
How I see it now, we should stay away from real SAS - and use NL SAS and rather buy another storage unit.
Answer
Yes, SAS drives are worth the cost. Error-correction, the SAS protocol and more predictable failure modes give SAS drives an edge over SATA.
If those reasons aren't compelling, you can certainly use SATA, but design for eventual failure. Use a robust RAID level and try to avoid the mixing SATA and SAS disks on SAS expanders (if possible, try to avoid expanders entirely).
See: How can a single disk in a hardware SATA RAID-10 array bring the entire array to a screeching halt?
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