Re: [BackupPC-users] Hardlinks & SMB Permission Errors

[Adam G. <mai...@we...>]

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Ashley Paul James wrote:
>>> (Ubuntu 7). This did not work either has i receive permission errors
>>> trying to write to the NAS drive.
>>> I used this string to mount the drive:
>>> smbmount  //192.168.10.70/ /var/lib/backuppc -o
>>> username=backuppc,password=backuppc,uid=backuppc,gid=backuppc.
>>> Ive substituted smbmount for 'mount -t cifs' as well.

AFAICT, SMB and CIFS do not allow to create hardlinks.

>>> Another solution was to create a symlink between /var/lib/backuppc
>>> and the storage device.  All this did was create a broken symlink on
>>> the NAS drive which cannot be removed.  A symlink will work fine if
>>> created in my home directory. Is it true that Symlinks cannot be
>>> created across different filesystems? In this case ext3 and xfs

symlinks can cross filesystems, but hardlinks can't. Your backuppc FS is
either smb or cifs, so I think the hardlinks will not work regardless of
your NAS type. BTW, a symlink should always be able to be removed, it
sounds to me like your NAS is not behaving very well, but I also don't
think this is your current problem.

>>> This situation is becoming very frustrating as its taken so long
>>> trying to resolve this issue. Every close door opens another one.

True, it seems that way, but really all those problems were all there at
the beginning, you just didn't realise it. So the more you solve, the
closer to the end of the list of problems you will get. Congratulations
on making it this far.

>>> Im about to go out and spend $700CDN on a new NAS drive that will
>>> support NFS. But need to know if this will resolve the issue or
>>> create the same problems.

I think NFS will support hardlinks, but better do some research and
confirm that first. Also, you should check what filesystem the NAS will
use internally to ensure it is capable of hardlinks.

>>> Is there a NAS hard drive which runs the ext3 file system? Surely
>>> this would work. 

I'm not sure, I spent some time last night looking for a 4 disk NAS
capable of NFS, and then cheapest I found was around AUD$1500 for a 1TB
system. If anyone knows of something more economical, which works
reliably (most important for me) please let me know (maybe off-list
since this might be off-topic)...

>>> What about reinstalling the OS using a different file system?
>>> Would it make a difference if I reinstalled BackupPC using source
>>> instead.  Not the best option but you have the opportunity to
>>> redirect the TOPDIR allowing the cpool/pool dirs to follow.

This shouldn't make any difference at all, except you will start with a
new list of problems, and eventually you will get to the exact same spot.

Performance will be pretty bad, but perhaps you could try something like
this:

mount your existing NAS to /mnt/storage (or somewhere other than
/var/lib/backuppc)
dd if=/dev/zero of=/mnt/storage/backuppc.img bs=1024 count=200000000000
That should create a 200GB file
If that doesn't work, try mounting with CIFS, if it still doesn't work,
then this will end up being somewhat more challenging, but not
impossible (could create lots of 2GB files and join them with LVM or RAID0)
Then "mke2fs /mnt/storage/backuppc.img"
Then "mount -o loop /mnt/storage/backuppc.img /var/lib/backuppc"
Then you are using an ext2/ext3 filesystem which is actually stored on
your NAS.

BTW, some of those commands might need adjustment/etc, but if you think
the concept is OK, then go ahead and try it, and ask more questions here
if you need to.

PS, IMHO, I think it is a bad hack, but sometimes you just need to work
with what you have. Also, you might have better success with an external
USB HDD (or external SATA HDD) which you can format locally and dedicate
to backuppc.

Regards,
Adam
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