drbd-user March 2010 archive
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drbd-user: Re: [DRBD-user] drbd slow sync and 3ware controller

Re: [DRBD-user] drbd slow sync and 3ware controller

From: Igor Neves <igor_at_nospam>
Date: Mon Mar 29 2010 - 16:00:15 GMT
To: drbd-user@lists.linbit.com

Hi,

Apart from any problem you may have in your setup, consider stop using
3ware controllers and buy areca. 3ware controllers are very, very slow.

You may try to get ride of software raid too, you shouldn't setup drbd
over OS disks too, you should split everything. I know almost everyone
want to spend less money possible but setting up data on top of your OS
disks it's terrible bad ideia!

Good luck.

On 03/28/2010 08:14 PM, Radu Rendec wrote:
> Hello,
>
> I have 2 (storage) servers running drbd on top of LVM logical volumes.
> Server 1 has hw raid 5 with 3ware 9650 controller and server 2 has raid
> 5 sw raid. I'm using protocol C, syncer rate 50M.
>
> The only problem is sychronizing from server 2 to server 1 (actually
> writing to the 3ware card) - I only get 5-6 M / s, with all CPUs on
> server 1 in ~100% iowait.
>
> And now the really strange thing: this only happens during sync. Once
> the sync is complete, I can successfully write at ~ 50M/s on server 2
> drbd device, with almost no load on server 1.
>
> Syncing from server 1 to server 2 (writing to the sw raid) works as
> expected: ~ 50M / s, no load on either servers.
>
> The issue seems to be related to the combination between the 3ware card
> and the drbd (initial) sync. But I'm totally clueless, since I can't
> figure out what's the difference between the initial sync and writing
> data when it's already synchronized.
>
> I'm kindly asking for any suggestions. If you reply, please cc my
> address (I'm not subscribed to the list).
>
> TIA,
>
> Radu Rendec
>
>
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-- Igor Neves<igor.neves@3gnt.net> 3GNTW - Tecnologias de Informação, Lda SIP: igor@3gnt.net MSN: igor@3gnt.net JID: igor@3gnt.net PSTN: 00351 252377120 _______________________________________________ drbd-user mailing list drbd-user@lists.linbit.com http://lists.linbit.com/mailman/listinfo/drbd-user