On Tue, Sep 28, 2010 at 11:15 AM, Eric Shubert <ejs@shubes.net> wrote:

> Alan Dayley wrote:
>
>> Maybe http://www.otisworldwide.com/ ?
>>
>> (Sorry, couldn't resist.)
>>
>> Side track: What does the word "elevator" mean in the context of RAID?
>> Ha!
>>
>
> In the linux kernel, the I/O scheduler is referred to as the elevator. It
> can be set to one of 4 values in the 2.6 kernel using the elevator= kernel
> parameter at boot time. Each block device's scheduler is determined by the
> value in /sys/block/<device>/queue/scheduler
> $ cat /sys/block/sda/queue/scheduler
> noop anticipatory deadline [cfq]
>
> You can change a device's elevator on the fly by doing:
> # echo deadline >/sys/block/sda/queue/scheduler
>
> I'm just wondering which value gives the best performance when using
> software raid-1, or if the choice depends more on the type of load that's
> being processed.
>
> Thank you, Eric.  I did not know about that kernel setting.

Alan