Dexter Filmore wrote:
ZFS is software. Don't know how ZFS performs, but being software I *bet* it won't write 400MB/s like a hardware controller does. (Ok, 400 at a sufficient high disk number, 6 or 8). I got soft raid 5 on my server and besides that it is troublesome in terms of stability (had at least 6 occurances where a disk flew from the array for no apparent reason, disk checks turned out disk was fine so I re-added it each time) it does little more then 10MB/s writes at cost of many cpu cycles.
Your first statement makes no sense. That hardware controller runs software too. There is no such thing as "hardware is better than software" or vice versa. They are apples and oranges. You cannot have one without the other. And RAID 5 sucks in general for performance. On a P4 system, XOR computation can be performed by the MMX unit (independently of the main cpu) at 2Gbytes/sec, well above the needs of I/O systems. So the RAID calculations themselves aren't likely to be causing noticeable CPU performance differences. In every case that I have had a machine kicking out disks from a Linux software RAID it was because there was some issue with either the hardware or the hardware driver. Some of them have even been intermittent issues where I could put the disk right back in and it would work fine.
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