[DRBD-user] Meta device too small in 8.3.2
lars.ellenberg at linbit.com
Sat Jul 18 12:34:40 CEST 2009
On Fri, Jul 17, 2009 at 06:17:35PM +0200, Raoul Bhatia [IPAX] wrote:
> On 17.07.2009 16:51, Gianluca Cecchi wrote:
>> On Fri, Jul 17, 2009 at 4:22 PM, Gianluca
>> Cecchi<gianluca.cecchi at gmail.com> wrote:
>>> drbd is 8.3.2 and O.S. is F11 x86_64 with kernel 220.127.116.11-191.fc11.x86_64
>>> I read in previous posts that an external meta device of about 4Mb is
>>> sufficient for about 100Gb od drbd device
>>> In my case with 8.3.2 it seems that 8MB are not enough for 52Gb.
>>> I have:
>> Ok, perhaps it was my fault understanding man page.
>> It seems that when you use meta-disk you have to use index and in that
>> case you need at least 256MB????
> as far as i recall you need *exactly* 256mb for your meta disk.
get your facts straight.
you need _exactly_ 128 MiB _per_ _index_ .
which, btw, also means that this form of fixed size external meta data
limits usable device size to slightly less than 4TiB.
so if you plan to use /dev/whatever only,
/dev/whatever needs to be at least 128 MiB.
if you plan to use /dev/whatever, .... /dev/whatever,
then it needs to be at least 16*128 MiB == 2 GiB.
> if /dev/cciss/c0d0p4 is for example 1gb in size, then you can use
> /dev/cciss/c0d0p4 throu /dev/cciss/c0d0p4 to store 4 drbd
nope, on 1GiB, there is enough room for 8 indexed,
fixed size drbd meta data blocks.
if you want to go for external meta data,
you'd be more flexible with flexible-meta-disk on LVs.
: Lars Ellenberg
: LINBIT HA-Solutions GmbH
: DRBD®/HA support and consulting http://www.linbit.com
DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.
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