[DRBD-user] Poor fsync performance

Andy Dills andy at xecu.net
Fri Jan 11 15:10:08 CET 2013


On Fri, 11 Jan 2013, Shaun Thomas wrote:

> On 01/10/2013 11:49 PM, Andy Dills wrote:
> 
> > So, it seems to me that even with the no-disk-barrier and no-disk-flushes,
> > when I am connected, I am limited (write speed) to the speed of the
> > network connection.
> 
> These options are only so you're not *also* constrained by buffer flushing and
> barrier operations. In the default protocol C, all writes must be synced on
> both nodes before they're successful. That means your writes will be, at most,
> the speed of your network interface.
> 
> We use dual 10Gb NICs on all of our servers, and bond them to separate
> switches for redundancy. I didn't want to go overboard so I gave DRBD a
> bandwidth limit, but I can get 350MBps from each of the 2 DRBD devices I have
> set up on our servers, and have plenty left over.
> 
> I really wouldn't suggest running DRBD *without* a 10Gb NIC.

Thank you, this is what I was starting to suspect, but hadn't seen 
explicitly stated anywhere. 

Any positive recommendations on 10Gb NICs?

Andy

---
Andy Dills
Xecunet, Inc.
www.xecu.net
301-682-9972
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