On 2014-09-08, Valeri Galtsev <galtsev at kicp.uchicago.edu> wrote: > > Even more: system failure or power loss is more likely to destroy all data > on software RAID than on a single drive when there is a lot of IO present > (to the best of my understanding, loss of cache software RAID is using is > more catastrophic compared to journaled filesystem under same > circumstances - somebody may correct me). So, there may be worth thinking > about hardware RAID. I think an essential feature of any md RAID that's not a RAID1 is a UPS and a mechanism for a clean shutdown in case of extended power failure. (An md RAID1 might be okay in this instance, but I wouldn't want to risk it.) But this is true for any RAID, which is why many controllers come with a BBU (and if you don't have a BBU on your hardware RAID controller, then you absolutely need the UPS setup I described). OTOH, the OP wasn't clear on what he was doing; perhaps he is just playing around, and doesn't care about data preservation at this time. If you're just testing performance then data integrity in the face of a power failure is less of a concern. --keith --keith -- kkeller at wombat.san-francisco.ca.us