rsync'ing partitions: what about /sys ?

[Pierre Baco]

Hi guys (and girls). I'm working on a simple script to mirror my partitions on a spare disk using rsync, and I've a question about the /sys dir: should I rsync it or just exclude it ?

 

What I want is a spare disk I could swap with the original one in case of serious trouble. Both disks (hda and hdc) have the same size. I've just 2 partitions (/ and /home) on hda.

 

I've done a first dd if=/dev/hda of=/dev/hdc to duplicate the whole disk including MBR. Now I want to run a rsync script every night to update hdc, something like

 

mount /dev/hc1 /mnt/sync_dir

rsync -uravH --delete --exclude-from=exclude_root.lst / /mnt/sync_dir

umount /mnt/sync_dir

mount /dev/hc2 /mnt/sync_dir

rsync -uravH --delete --exclude-from=exclude_home.lst /home /mnt/sync_dir

umount /mnt/sync_dir

 

It works fine (0 errors) for /home but I get a rsync error 23 ("some files could not be transfered") while rsync'ing / when /sys is not in the exclude_root.lst file, which looks like:

/proc

/mnt

/home

/etc/fstab

/tmp

 

I know /sys has something to do with udev and hotplugging. Is it safe to exclude it ? (i.e. Will the spare disk boot correctly if /sys has not been updated ?).

 

Thanx in advance for your (always appreciated) input.;)

 

Pierre

[Steve Scrimpshire]

I'm no expert, but it's my opinion that it won't matter.../sys should be populated dynamically. I'm surprised you didn' get errors rsync'ing /proc as well, because it should be dynamic also.

[iphitus]

sys/sysfs is information generated by the kernel, in a similar way to proc.

 

Im just thinking that if you want to have your partition mirrored, you could probably do something with software based raid.

[Pierre Baco]

Thanks. I'm gonna exclude /sys just like I did with /proc and give a try to reboot with the spare disk after a full rsync.

 

Pierre