Luke Lonergan wrote:
Jim,
On 1/30/06 12:25 PM, "Jim C. Nasby" <jnasby@xxxxxxxxxxxxx> wrote:
Why divide by 2? A good raid controller should be able to send read
requests to both drives out of the mirrored set to fully utilize the
bandwidth. Of course, that probably won't come into play unless the OS
decides that it's going to read-ahead fairly large chunks of the table
at a time...
I've not seen one that does, nor would it work in the general case IMO. In
RAID1 writes are duplicated and reads come from one of the copies. You
could alternate read service requests to minimize rotational latency, but
you can't improve bandwidth.
- Luke
For Solaris's software raid, the default settings for raid-1 sets is:
round-robin read, parallel write. I assumed this mean't it would give
similar read performance to raid-0, but I've never benchmarked it.
-Kevin
