[Dirvish] Replacing backup drive

Jim Conger jconger at foobox.com
Sat Jul 14 00:55:12 UTC 2018


On 07/13/2018 07:42 PM, Rich Shepard wrote:
>     I've been using dirvish for many years and my external backup drive (a
> nominal 500G with fdisk -l reporting capacity as 465.8G) is getting full. In
> fact, a couple of weeks ago it ran out of room so I deleted the most ancient
> directories so it's now at 95% capacity. (I don't recall every needing to
> restore a file or directory from a backup more than a week in the past.)
>
>     I now have a new 2T Hitachi drive. Looking on the dirvish web site the
> link to the old guide cannot find that page, and I don't recall how to set
> up the replacement drive.
>
>     My questions:
>
>     1. The current server (to be replaced Real Soon Now) uses ext3. Can the
> backup drive be formatted using ext4?
Yes.  Dirvish backs up using rsync, a user mode operation. All it needs 
is a good place to write the files. It's not a disk image backup of some 
sort that is mirroring file system objects. I have had some odd problems 
with corruption in ext4 file systems with vaults in them, so I fsck the 
vault file system after every backup. I think I read something about 
ext4 and hard links being a problem which would be bad news for dirvish 
since it is all about hard links. I'm happy with ext4 as long as I check 
it each time. You could try something else, but there are recovery 
challenges with some other file systems.  I'll let someone with more 
experience chime in on that.
>     2. The current server has multiple partitions (a remnant from the mid- to
> late-1990s); the vault has these mount points:
> # ls /mnt/hd/
> lost+found/  salmo-home/  salmo-root/  salmo-var/
> salmo-boot/  salmo-opt/   salmo-usr/
>
>     The new server will have have /, /home, /root, /boot, /opt, and /data on
> two drives.
It doesn't matter how many physical drives hold the file systems
> TIA,
>
> Rich
>
> _______________________________________________
> Dirvish mailing list
> Dirvish at dirvish.org
> http://www.dirvish.org/mailman/listinfo/dirvish
you are backing up, you are still backing up files from within file 
systems. It looks like you can rsync your current vaults from /mnt/hd to 
the new 2T drive's file system and then add a vault for the new /data. 
There are some other clever things you can do, like using LVM on the new 
2T drive to make it easy to mirror or resize file systems because they 
would be in volumes instead of partitions. You could use a volume and 
file system for each file system's vault if you want to protect some 
against file system corruption for the vaults.
>     3. Is there a better scheme for the vault? How about adding a / directory?
I'm not sure what you are asking.  I am sure that your / file system is 
backed up to salmo-root, that's what I do. You could mount it somewhere 
other than /mnt/hd, but it doesn't really matter. I backup multiple 
hosts over the network, so I have a file system with vaults for each 
source host mounted in a /backup directory.
>     What advice do you computer professionals have for me germane to dirvish
> and replacing the backup drive?
Partition, create volumes, make file systems, etc. on the new 2T drive 
with out the current backup connected.  Avoids accidents.

When you are ready to copy, mount the old backup drive read only, "mount 
-o ro /dev/WHATEVER /mnt/hd". Avoids accidents. Voice of experience.

Use rsync with all the right options to copy pretty much every detail, 
see man page for rsync, but "rsync -a --stats /mnt/hd/. /mnt/NEWDRIVE/." 
should do it. Note the trailing /. on the paths, that makes sure you are 
copying everything in the old to the new, including the permissions of 
/mnt/hd/. itself.

Keep the old drive around for a few weeks or months to make sure 
everything is going well.

Consider rotating between two backup drives to protect against failures 
of the backup drive itself.

Hope this helps.  I'm an SA among other things and I do use Dirvish as 
my home backup system.

Jim

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