On Mon, Dec 21, 2015 at 7:36 PM, Tejas Rao <raot@xxxxxxx> wrote: > > We currently have 10's of petabytes in production using linux md raid. We > are currently not sharing md devices, only hardware raid block devices are > shared. In our experience hardware raid controllers are expensive. Linux > raid has worked well over the years and performance is very good as GPFS > coalesces I/O in large filesystem blocksize blocks (8MB) and if aligned > properly eliminate RMW (doing full stripe writes) and the need for NVRAM > (unless someone is doing POSIX fsync). > Full Stripe Write does not eliminate the need for NVRAM. Stored data under MD RAID-6 is vulnerable to write-hole data corruption issue. Yes, hardware RAID controllers are expensive because they would provide more data reliability and high-availibiltiy that might not be useful for this use case. --Alireza -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
