Re: [9fans] venti backup

[hugo rivera <uair00@gmail.com>]

There's something weird going on. First checkarenas reports

% venti/checkarenas -v /dev/da1s4
arena='arenas00' [802816,537673728)
        version=5 created=1265030300 modified=1265248834 sealed
        score=f383ebf9edefe8d37733c8caba6ff53e8b5517b0
        clumps=82,908 compressed clumps=22,812 data=669,897,790
compressed data=531,617,136 disk storage=536,840,340

that's only 98 blocks of 8192 bytes, not 128 as you mention.
Anyway, I run fmtarenas on fa and then if I

% 9 dd -if /dev/da1s4 -of fa -bs 8192 -iseek 98 -oseek 98 -count 65536

or

% # this doesn't make sense but I've tried it, nevertheless
% 9 dd -if /dev/da1s4 -of fa -bs 8192 -iseek 128 -oseek 128 -count 65634

I get

2012/0120 11:57:10 err 2: arena set has wrong magic number: 00000000
expected ArenaPartMagic (0xa9e4a5e7)
venti/buildindex: can't init venti: can't initialize venti: fa: arena
set has wrong magic number: 00000000 expected ArenaPartMagic
(0xa9e4a5e7)

when I run buildindex, and checkarenas says the same thing.


2012/1/20 David du Colombier <0intro@gmail.com>:
> To clarify things.
>
> You backup is correct, but it's not necessary to backup the
> first 128 blocks of the arena partition. Its only contains
> the Venti configuration and the ArenaPart structure.
>
> Here is an example of what I described in my precedent message.
>
> Create an arena partition at least as big as your original
> one, and format it:
>
> % dd -if /dev/zero -of arenas.img -bs 8192 -count 4194304
> % venti/fmtarenas arenas arenas.img
>
> Then copy your Venti arenas from the beginning of arenas00
> (128*8192) to the end of arenas059 (3932258*8192):
>
> % dd -if /dev/da1s4 -of arenas.img -bs 8192 -seek 128 -oseek 128 -count 3932258
>
> Of course, '/dev/da1s4' can be 'fa' in your example.
> If you removed the first 128 blocks, you don't have
> to use '-seek'.
>
> Finally, write the Venti configuration, rebuild the index
> and Bloom filter, and start Venti.
>
> --
> David du Colombier
>



--
Hugo