Re: 12 disks raid setup

On Sat, 1 Mar 2008, Shane Ambler wrote:

> It may be the way you have worded this but it makes it sound like the
> cache and the battery backup are as one (or that the cache doesn't work
> unless you have the battery)...If the raid card has the cache without
> the battery you would get the performance figures you mentioned, you
> just wouldn't have the reliability of finishing writes after a power off
> situation.

Wording is intentional--if you don't have a battery for it, the cache has
to be turned off (or set to write-through so it's only being used on
reads) in order for the database to be reliable.  If you can't finish
writes after a power off, you can't cache writes and expect your database
to survive for too long.

--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD