Re: [BackupPC-users] copying the pool to a new filesystem?!

Am 02.12.2010 14:05, schrieb Carl Wilhelm Soderstrom:
> On 12/02 01:27 , Oliver Freyd wrote:
>> The pool is a reiserfs3 on LVM, about 300GB size, but with a lot of
>> hardlinks...
>> Now I'm trying to put the pool onto a new filesystem, so I created an
>> XFS on a striped RAID0 of 3 disks (to speed up copying), and use
>> rsync -aHv to copy everything including the hardlinks.
>> The cpool itself took about a day, and now it is running for 6 days and
>> maybe it has done 70% of the work. BTW, a copy with dd takes about 2 hours.
>
> Yep. this is normal. you've discovered why backing up the BackupPC data pool
> with rsync is a non-scaleable solution.
>
> As you noted, dd is the way to go if at all possible.
>
> If you want to change the filesystem (i.e. make a file-level copy); best
> thing is to use tar.
>
> Presuming that your old data pool is under /var/lib/backuppc and the new
> filesystem is mounted on /mnt/newfilesystem:
>
> cd /var/lib/backuppc; tar cpf - . | tar xpv -C /mnt/newfilesystem
>
>
> Is the use of RAID0 on 3 disks a temporary thing? Keep in mind that the more
> disks you have the greater the likelihood that one of them will die. With
> RAID0 if one dies you lose all your data.
>
Thank you for the quick answer, I knew that rsync would need a lot of 
memory to keep track of the hardlinks, but that it would be that slow...

Maybe I'll try the tar approach, for now I'll just let it run on.

The RAID0 is just temporary, I tried the rsync before onto a single 
disk, and that was even slower, but definitely the gain is not much, 
especially in the hardlink-copying phase.
When the rsync has succeeded, I'll dd the pool back into an LVM volume, 
which lives on a RAID1 (2 disks mirrored).

Regards,
        Oliver



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