[DRBD-user] Configuring the scheduler for a DRBD backend

Lars Ellenberg lars.ellenberg at linbit.com
Tue Jul 16 16:16:41 CEST 2013

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On Mon, Jul 15, 2013 at 06:14:16PM +0200, Wiebe Cazemier wrote:
> ----- Original Message -----
> > From: "Lars Ellenberg" <lars.ellenberg at linbit.com>
> > To: drbd-user at lists.linbit.com
> > Sent: Monday, 15 July, 2013 5:56:51 PM
> > Subject: Re: [DRBD-user] Configuring the scheduler for a DRBD backend
> > 
> > Why not just use deadline as default scheduler, and be done with it
> > ;-)
> > (kernel boot parameter elevator=deadline)
> Well, for one, one of the server has a hardware RAID controller (3Ware
> 9650 SE), and 'they' say that in that case, noop is better. I haven't
> decided if that's true, because I didn't know that hardware RAID
> performed scheduling. I just thought it did whatever it was told by
> the OS.
> But, you're saying deadline is better overall?

Never said that.
If that really were the case, it would not be a tunable ;-)

It is our general recommendation, though.
Which means "in most cases you get good results with minimum effort".

If you want to know what's "best" for your workload,
you have to first define "best" for your situation,
and figure out how to benchmark/measure it.
Then you have to measure with your workload.
No way around that...


: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

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