汽车防晒隔热罩品牌:请问，如何做双机热备份。请详细解释！

bsd下如何做双机热备份？

我从mail list找到这个， 也许你可以试试！

>; I'm trying to create an offsite "hot backup" of a FreeBSD server. If
>; the primary server fails, I want to transport the spare machine to the
>; existing site and bring it up as a replacement, with little or no
>; reconfiguration necessary.
>;
>; Nightly mirroring would be adequate in this situation. The system is
>; not running live transaction processing or anything comparable.
>;
>; Is there a straightforward, automated way to mirror a whole FreeBSD
>; system, using open source software?
>;
>; I'm testing ftpcopy to remotely mirror the files and directories.
>; Ftpcopy performs an incremental comparison using dates and file sizes,
>; which should minimize the nightly backup time and traffic load. So far
>; that part seems to be working well.
>;
>; But I haven't figured out how to get the users, groups and permissions
>; mirrored. There are about 200 users. And there may be other gotchas I
>; haven't thought of yet.

The approach I am using is to tar the system to a file on the
production machine and then rsync that file with my off-site backup
machine. I leave it as a tar file on the backup as its almost
impractical for me to move that machine to the production site. I
would replace the machine on the production site and then copy the file
back from the backup machine and un-tar it.

In your case I would create the tar file, rsync it to the backup
machine and then un-tar it there. Tar retains permissions and
ownership properly. Leave the previous tar file on the backup machine
as rsync will use it to reduce the download time. My backup file (4
servers) is just over 4 GB. The rsync transfer only sends 1/16th of
it. Much of the archived data does not change very often.

Sounds to me like this is a job for rsync(1) --- see
http://rsync.samba.org/ or net/rsync in ports. You can use rsync to
maintain a remote copy of a partition, as you describe. rsync(1) will
transmit only the minimum necessary over the wire in order to bring
the two filesystems into synch. Eg. to save or update a copy of the
/var partition on your live server to a backup machine:

# rsync -avx --delete /var/ backup.example.com:/backups/var/

By default on FreeBSD, rsync(1) will use ssh(1) for remote shell
access. For unattended access you probably need to set up appropriate
ssh keys without passwords, but definitely limiting access based on
the 'from=' hostname and/or command used via options in the
~/.ssh/authorized_keys file, as described in the 'AUTHORIZED_KEYS FILE
FORMAT' section of sshd(8) -- you should also turn off the three types
of forwarding with an autologin key. See also
http://www.snailbook.com/faq/no-passphrase.auto.html

Cheers,

Matthew