[DRBD-user] painfully slow sync

dave at gottathink.com dave at gottathink.com
Tue Jan 27 23:15:11 CET 2004

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


Quoting Peter Stamfest <peter at stamfest.at>:

> 
> On Mon, 26 Jan 2004, Dave Dunkin wrote:
> 
> > On Jan 26, 2004, at 4:26 PM, Lars Ellenberg wrote:
> > 
> > > / 2004-01-26 15:48:14 -0600
> > > \ dave at gottathink.com:
> > >> Quoting Lars Ellenberg <Lars.Ellenberg at linbit.com>:
> > >>
> > >>> / 2004-01-25 23:38:08 -0800
> > >>> \ Dave Dunkin:
> > >>>> I've got drbd set up on two RedHat 9 nodes with 60GB software RAID1
> > >>>> devices I'm trying to mirror. I started it up for the first time 
> > >>>> and it
> > >>>> started with a SyncAll from the primary to the secondary at around
> > >>>> 10MB/sec (on a private 100Mbps network). Then at almost exactly 30%
> > >>>> though the sync, the sync speed dropped to an abysmal 500KB/sec. 
> > >>>> I've
> > >>>> tried upping the minimum and setting the nice level, but nothing 
> > >>>> seems
> > >>>> to improve the situation. I tried stopping and restarting the sync
> > >>>> process and the same thing happened at 30%.
> 
> 
> I am repeating myself (have a look at the list archive, it might even be a
> FAQ): I have seen this with cheap NICs. Switched to 3com cards and
> everything went fine afterwards. This was a long time ago (0.6.1_pre
> something). I do not know if this problem has ever been identified and
> solved and I do not know if DRBD is to blame for it at all. 
> 
> I never saw this problem with anything else than DRBD, though - this might
> be because only DRBD was able to saturate the link for long enough for the 
> problem to appear.

I'm using the built in ethernet port on the machines. They are VA-Linux 1000s,
which are really rebranded IBM Netfinity 4000Rs. The use Intel Pro Ethernet
10/100 (I think it's the i82557/i82558 chipset, but I don't have access to the
machine at the moment). I do have the cards set up to be bonded for redundancy.
I'll try disabling that and see if it helps.


Dave







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