[DRBD-user] slow synchronisation with 3ware RAID arrays

Lars Ellenberg lars.ellenberg at linbit.com
Mon Sep 6 10:18:59 CEST 2004

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

On Sun, Sep 05, 2004 at 07:50:05PM +0200, Christian Garling wrote:
> Hello,
> the troughput is NOT 12kb/s, it is 12000kb/s. I had read it wrong, because
> 12,123 looks for me like 12 and not like 12000. But this is almost slow.
> The harddisks can do 25MB/s and the network is a directly gigabit
> connection. I use RAID 5 too with a 3Ware Escalade 7506-4P and three
> Seagate Baracuda 160GB harddisks. A fullsync takes round about 6 hours.
> Thats OK, but it could be better, because the 12000kb/s are less than 50
> percent of the speed that theoretically must be usable.

but that is not a problem with DRBD then,
let me quote you:

> Network link tested with iptraf. I sent a 190MB Package over the two
> gigabit cards and measured a speed of 12MB/s. So I think the network
> cards are alright. 

and be aware that using drbd 0.7, you almost never see a "full sync"
anymore, typically at most a sync of the extents covered by our activity
log, and that will be done within one to five minutes depending on your
config and hardware, regardless of device size.

	Lars Ellenberg

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