With SSD prices coming down, does it make more sense to run software RAID with SSDs instead of paying for a hardware RAID controller and BBU, especially when considering the cost of SSD caching for the RAID controller?
Yes, there's quite a bit less space. Only one of our nodes is using over 1tb of storage, and most are under 500gb. A bit of data analysis earlier today shows that our average disk space allocation is 13 gigabytes, and average usage is 4.3 gigabytes.
I've typically been an ardent detractor of software RAID, but this is due to mdadm's psychotic self-checks that happen at the worst times and cause extreme load averages. This results from mdadm trying to check the disks while the processes running on the node are still trying to operate; I don't think this contention would result if using SSDs.
What are your thoughts? Would you use a host that's using software RAID with SSDs? Any other input on the subject?