[DRBD-user] flexible-meta-disk for multiple drbds ?

Lars Ellenberg Lars.Ellenberg at linbit.com
Fri Jan 19 13:33:24 CET 2007

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


/ 2007-01-19 12:25:31 +0100
\ Ralf Schenk:
> Hello !
> 
> I want to use drbd (0.8rc2) on top of two logical volumes. Can I use the
> "flexible-meta-disk" on a third logical volume as meta-disk for both
> drbd devices ?
> 
> I tried setting "flexible-meta-disk /dev/VG/drbd[0]" and
> "flexible-meta-disk /dev/VG/drbd[1]" which doesn't work.
> 
> I now used "meta-disk /dev/VG/drbd[0|1]" which is ok, but in the manual
> there is areference to LVM for the flexible-meta-disk
> 
> "With the flexible-meta-disk keyword you specify a block device as
> meta-data storage. You usually use this with LVM, which allows you to
> have many variable sized block devices."

"meta-disk" is fixed size, and takes an index.
"flexible-meta-disk" uses only the space needed,
and does not understand and index.

what we usually do is have a lv for the storage,
and an lv for the meta data.

storage_size_in_GB=500
# storage lv is drbd0
lvcreate -n drbd0 -L ${storage_size_in_GB}G ... <vgname> ...

# very rough formula
meta_data_size_in_MB=$[2 + storage_size_in_GB / 32 ]
# will round it up to the next multiple of PE size anyways:
# meta data lv is drbd0-md
lvcreate -n drbd0-md -L ${meta_data_size_in_MB}M ... <vgname> ...
then use flexible-meta-disk drbd0-md 

hth,

-- 
: Lars Ellenberg                            Tel +43-1-8178292-0  :
: LINBIT Information Technologies GmbH      Fax +43-1-8178292-82 :
: Vivenotgasse 48, A-1120 Vienna/Europe    http://www.linbit.com :
__
please use the "List-Reply" function of your email client.



More information about the drbd-user mailing list