SSD drives can provide high performance but due to the same reason and because of the cost of SSD drives most of the providers are forced to host the maximum number of accounts in the server which eventually slow the server performance. If CloudLinux is utilised in the server it will have a set limit for resources and help the host to increase account density in the server.
An underutilized SAS drive would be great for hosting purposes.
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We have found HGST Ultrastar 7K4000 drives to be the most relialble (MTBF 2Million hours) out of the hard disk drives we have tested. They cost quite a bit more but they increase reliability and require fewer man hours to maintain.
For SSD's we went with Intel for our last few servers, they also have a MTBF of 2M. hours but we haven't used them for long enough to give an oppion on their durability (the older models have proven to be very durable).
We now use SSD's for webservers (last server has 12x800GB in Hardware Raid 10. and are waiting for cPanel to provide a mail only version to use HDD's for e-mail hosting. Our backup servers have 12x4TB HHD's in software raid 10.
It depends on the application. For most of our projects Western Digital RE SATA drive work well. If we need a little more performance then move up to SAS and when we need top level performance, SSD. It also depends on budget and amount of storage needed.
One drawback that we've seen with SSD drives is that they seem to completely fail all at once. We've had non RAID SATA and SSD drives fail and have almost always been able to recover data from a failed SATA drive, but that hasn't been the case with failed SSD drives.
SSD drives we've used have been Intel and Samsung, depending on price and performance.