[DRBD-user] priblem with replicating volumes which are over 2 TG

Philipp Reisner philipp.reisner at linbit.com
Wed Aug 24 10:35:13 CEST 2005

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

> hello drbd users
> I've got another problem. I am unable to start a DRBD device with over 2TG
> volume. My environment is kernel 2.6.10, DRBD 0.7.11, newest LVM2 and XFS.
> The attachment is the dmesg from both source and target side.
> According to the log, source and target side seems connected then broked
> up, and there is weird error message in the kernel log: allocation failed:
> out of vmalloc space - use vmalloc=<size> to increase size.
> If I try to execute "drbdadm state LV", the primary side shows
> "secondary/unknown", however insecondary side, it sometimes shows
> "secondary/secondary", sometimes shows "secondary/unknown"

Hello David,

By now we know that you try to exprole the limitations of DRBD. 
As the stable code base is a single DRBD volume is limited to nearly 
4TB, but as you found out that is not practical since the VM layout
of the kernel does not allow us to allocate linear (in virtual addresses,
not in physical) memory large enough to hold the bitmap.

We at LINBIT have an "enterprise" fork of DRBD that overcomes this
limitations. It is in productions at a site where 15 TB of storage in 
sum are mirrored by DRBD on a 32 bit kernel.

We will market this product soon, probably along with a restructuring 
of our support contracts, but it all takes so time...

  If you are interested in this, please contact me off-list.

: 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 :

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