[Drbd-dev] larger than 4tb volume status

[Drbd-dev] larger than 4tb volume status

[Federico Grau]

Hello,

What is the plan for supporting volumes larger than 4terabytes, I don't see
any mention to that in the svn ROADMAP file.

thanks,
donfede

-- 
Federico Grau
Free Software Developer and Sysadmin
Radio Free Asia
2025 M Street, NW
Suite 300
Washington, DC  20036
202-587-2046  Telephone
202-721-7468  Facsimile
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Re: [Drbd-dev] larger than 4tb volume status

[Philipp Reisner]

Am Dienstag, 7. November 2006 00:44 schrieb Federico Grau:
> Hello,
>
> What is the plan for supporting volumes larger than 4terabytes, I don't see
> any mention to that in the svn ROADMAP file.
>

Our current business model has two tree steams of revenue in the DRBD area

 * Support contracts
 * Doing projects, workshops and consulting in the DRBD area
 * Selling DRBD+ licenses

Wile keeping the basis technology open source...

In case you have two times 4TB of storage you spent already quite some
money on hard disks. In that case we expect you to support DRBD with
buying a DRBD+ license. See http://www.linbit.com/en/drbd/drbd-plus/2/

-Phil
-- 
: Dipl-Ing Philipp Reisner                      Tel +43-1-8178292-50 :
: LINBIT Information Technologies GmbH          Fax +43-1-8178292-82 :
: Schönbrunnerstr 244, 1120 Vienna, Austria    http://www.linbit.com :

RE: [Drbd-dev] larger than 4tb volume status

[Sylvain Coutant]

>  * Selling DRBD+ licenses

The web site doesn't make clear what is DRBD's current limitation, it states
:

- "single device is limited to 4 TB"
- "DRBD+ uses HIGHMEM[...]necessary in order to mirror over 4 TB in total
over all devices"


So, is it 4 TB total storage per node or 4 TB per drbd volume ? Is this
different for 32 bits and 64 bits systems ?


BR,
 
--
Sylvain Coutant

Re: [Drbd-dev] larger than 4tb volume status

[Philipp Reisner]

Am Donnerstag, 16. November 2006 10:06 schrieben Sie:
> >  * Selling DRBD+ licenses
>
> The web site doesn't make clear what is DRBD's current limitation, it
> states
>
>
> - "single device is limited to 4 TB"
> - "DRBD+ uses HIGHMEM[...]necessary in order to mirror over 4 TB in total
> over all devices"
>
>
> So, is it 4 TB total storage per node or 4 TB per drbd volume ? Is this
> different for 32 bits and 64 bits systems ?
>
>

I hope you do not use a proportional font to read your email:

              |         DRBD        |          DRBD+
--------------+---------------------+------------------------
per Device    |    4TiB             |    16iBT on 32bit  (2)
total         | ~4TiB on 32 bit (1) |    unlimited       (3)


(2) on 64 bit it is 2^72 Byte or 4 ZiByte or 4294967296 TiB

(1) You can do tricks with the kernel parameter vmalloc= 
    I do not know the exact limit by heart, but I guess you
    will not be able to reach 6 TB on a 32 bit system.
    On a 64 bit system it might be more (with vmalloc= tricks),
    but I do not know.

(3) Unlimited. But limited by available system RAM. DRBD 
    allocates 32KiByte BitMap (in RAM) for 1GiByte of Storage.

    Storage size   |  DRBD's RAM usage
    ---------------+------------------
       1 TiB       |       32 MiB
       32 TiB      |       1 GiB
       ...                 ...

PS: The largest Volume I know of running in production is 20TB!

-Phil
-- 
: Dipl-Ing Philipp Reisner                      Tel +43-1-8178292-50 :
: LINBIT Information Technologies GmbH          Fax +43-1-8178292-82 :
: Schönbrunnerstr 244, 1120 Vienna, Austria    http://www.linbit.com :

Re: [Drbd-dev] larger than 4tb volume status

[Philipp Reisner]

Am Donnerstag, 16. November 2006 12:18 schrieb Sylvain Coutant:
> > I hope you do not use a proportional font to read your email:
>
> Nice. Thanks.
>

I took this as cause to write a real DRBD-Fact sheet.

http://www.linbit.com/fileadmin/linbit/DRBD-Faktblatt.pdf
http://www.linbit.com/fileadmin/linbit/DRBD-Factsheet.pdf

linked in from the DRBD+ feature page.

-Phil
-- 
: Dipl-Ing Philipp Reisner                      Tel +43-1-8178292-50 :
: LINBIT Information Technologies GmbH          Fax +43-1-8178292-82 :
: Schönbrunnerstr 244, 1120 Vienna, Austria    http://www.linbit.com :

Re: [Drbd-dev] larger than 4tb volume status

[Federico Grau]

On Thu, Nov 16, 2006 at 09:47:06AM +0100, Philipp Reisner wrote:
> Am Dienstag, 7. November 2006 00:44 schrieb Federico Grau:
> > Hello,
> >
> > What is the plan for supporting volumes larger than 4terabytes, I don't see
> > any mention to that in the svn ROADMAP file.
> >
> 
> Our current business model has two tree steams of revenue in the DRBD area
> 
>  * Support contracts
>  * Doing projects, workshops and consulting in the DRBD area
>  * Selling DRBD+ licenses
> 
> Wile keeping the basis technology open source...
> 
> In case you have two times 4TB of storage you spent already quite some
> money on hard disks. In that case we expect you to support DRBD with
> buying a DRBD+ license. See http://www.linbit.com/en/drbd/drbd-plus/2/
> 

Thank you for the response Phil,

While I respect your business model, part of our organizations IT plan is not
to get trapped into subscription based technologies.  This is why we choose
(and support financially and time-wise) Free Software based solutions.  

A couple years ago 4TB was quite large, but with terabyte hard drives soon to
hit the market that is no longer the case.  Is there a roadmap or a list
changes on what needs to be upgraded on DRBD so that it can support more that
4TB or does someone from the community need to compile this?

regards,
donfede


-- 
Federico Grau
Free Software Developer and Sysadmin
Radio Free Asia
2025 M Street, NW
Suite 300
Washington, DC  20036
202-587-2046  Telephone
202-721-7468  Facsimile
CONFIDENTIAL COMMUNICATION
This e-mail message is intended only for the use of the addressee and may
contain information that is privileged and confidential.  Any unauthorized
dissemination, distribution, or copying is strictly prohibited.  If you
receive this transmission in error, please contact network@rfa.org.