[DRBD-user] Definitive answer on >4TB DRBD volumes

Lars Ellenberg lars.ellenberg at linbit.com
Tue Jul 22 12:55:08 CEST 2008

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


On Tue, Jul 22, 2008 at 12:09:39PM +0200, Iustin Pop wrote:
> On Tue, Jul 22, 2008 at 12:01:48PM +0200, Lars Ellenberg wrote:
> > 	you need 32 MB in core RAM per TB storage,
> > 	which is pinned by DRBDs bitmap.
> > 	that is 512 MB RAM for 16 TB total storage,
> > 	          1 GB RAM for 32 TB total storage.
> 
> Oh, this is very nice information, thank you. I'm curious if the memory
> requirements are the same for:
>   - one 4TB device and
>   - eight 512GB devices?
> 
> I guess yes, since you mention "total storage", but I wouldn't mind a
> confirmation :)

yes.
well, there is some additional mostly negligible (compared to the bitmap
memory consumtion) overhead per device.

but, yes.
  one 4TB needs 128 MB bitmap,
  eigth 512 GB devices need 16 MB bitmap each.

-- 
: Lars Ellenberg                           http://www.linbit.com :
: DRBD/HA support and consulting             sales at linbit.com :
: LINBIT Information Technologies GmbH      Tel +43-1-8178292-0  :
: Vivenotgasse 48, A-1120 Vienna/Europe     Fax +43-1-8178292-82 :
__
please don't Cc me, but send to list -- I'm subscribed



More information about the drbd-user mailing list