[DRBD-user] Re: Some questions about drbd

Helmut Wollmersdorfer helmut.wollmersdorfer at gmx.at
Wed Jul 6 12:31:33 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.

Sven Schuster wrote:

> 1. When the secondary node is down for some time, no mirrored
>    hard disk is replaced, how will it be re-synced when it comes
>    up again?? Will a complete resync take place, or just the
>    changed parts of the block device? 

Since Version 0.7.0 only the changed parts.

>    If just the changed parts
>    are synced, how are those changed parts determined, 

Ther is meta-data, see 'mata-disk'. In easy words, it is a bitmap, which 
parts are in sync or not in sync.

>    and what
>    is the order in which those parts are synced?? 

Any order. It is not comparable to a collection of 'after images', where 
the order would be important.

> 2. drbd is independent from the kind of block device which is
>    underneath it, right?? So, as long as the kernel itself can
>    use a block device, it can be used by drbd, regardless if it's
>    an ide drive, scsi, raid, or maybe even a ramdisk :-)

Yes. And add LVM to your list.

Helmut Wollmersdorfer

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