On Thursday 09 November 2006 05:22, Arie Reynaldi Z wrote:
Software RAID level 1 is slower than 1 harddisk? Not true. Writing and Reading speed is good. But, it's the most expensive solution in terms of money per MB. Software RAID level 5 is slower than 1 harddisk? Partly true. Writing performance is a bit slower since it must calculate the parity. Reading speed is good.
I googled and found this: http://www.catux.org/index.php?contingut=articles&num=101
It shows that using software RAID 1 is slower then others.. Can someone explain about this ? It used Bonnie++ just like Joachim said.
A mirror uses two drives. Data has to be written to both drives. File systems/buffers help hide this to some extent, but in the end twice as much work must be done, so it is reasonable to expect it to be slower for writes. But, as the charts on that web page show, the mirror is not twice as slow. So, a software Raid mirror is a good compromise for reliability and performance without spending big money on enterprise class hardware raid.