Re: [9fans] Disk backup?

[arisawa <arisawa@ar.aichi-u.ac.jp>]

thanks cinap,

I believed you are interested on this topic.

assuming we don't modify current cwfs code,
the only way to solve the problem is to have list of unwritten blocks up to last superblock 
(or bitmap of written blocks)
cwfs might manage the list, but I don't know where it is.

inspecting block tags of fsworm gives us information for having the list.
but my fsworm is old one that have been used elsewhere, and full of garbage data.
then block tag of fsworm is unreliable. 
we have small probability to misunderstand that some of unwritten blocks is as written blocks.
to avoid this problem, we must format fsworm putting some special tag on each block.
this will take long time, but only once.
do you have any alternative solution?


On 2013/03/25, at 13:36, cinap_lenrek@gmx.de wrote:

> i was thinking about this some time ago... theres the fakeworm
> device "f<subdevice>" that will maintain a block bitmap of
> the blocks that have already been written. one could write
> a program that also backups the block bitmap and on backup,
> compares the bitmaps prior copying blocks so only newly
> written blocks get backed up.
> 
> --
> cinap
>