Backing up a linkstation pro.

[howdoesthiswork]

   

Before I help/direct a colleague down a path which we both later regret, can anyone offer any advice on the following setup.

 

In a workgroup, a linkstation pro had been added to provide a medium to backup workstation files. I was asked to have a look and have diagnosed that the backup software couldn't cope with source/file paths in excess of 160 characters and couldn't handle open files either.

 

I had thought the linkstation (being a NAS) might replace the workstation as the workstation serves only as a data store.  Then the linkstation could be backed up to a USB drive and the workgroup would have a fast OS free data store backed up to a portable USB drive which could be removed off site as part of a disaster recovery policy.

Well, I least that's what I thought.  Investigation shows the USB hard drive format options are FAT32 or EXT3/XFS.  Should the linkstation fail, I thought, a FAT32 formatted backup would plug into a workstation and instant data accessibility - great!

But no, the FAT32 limitations of a 2GB file size are not  a real problem but the inbuilt backup limitation of 120 characters (correct me if I'm wrong, it might be 160) is no better than the current backup which also doesn't work.  If I use an XFS format, then the backup may work with >120 character file paths but could I plug the USB drive into a workstation and access the data? I doubt an XFS drive would be recognized by an NTFS client?

There's no mention in the manuals of the inbuilt backup's ability to deal with open files either, so that's unknown territory.

So, all in all, although the linkstation appears to be a fine NAS, there's not a lot of documentation on backing up data FROM the NAS - apart from using another linkstation (though that reads as being more straightforward than some of the forum entries would suggest).

Not sure either how a client backup application would be able to copy open files from the linkstation given that (unless I've got this wrong) the volume shadow copy service only applies to local files.

 

Just all seems a little vague.  Even the UPS capability seems 'unfinished'.

I received a reply from tech support regarding safe shutdown...

"Under Maintenance -> UPS Settings if it detects the UPS you'll see options for safe shutdowns and the like in there."

Not quite what I had in mind. Do I need to buy many UPS devices in the hope of finding a compatible model?  I know the linkstation pro can only sync using USB but if it's not really setup to work with a UPS then why bother adding half a solution?

 

Come on Buffalo... The plug and play functionality is fine but there appear to be a few 'beneath the surface' issues that either still need addressing or could be documented in much greater detail.

 

[kevin]

Here is all the information, about what can be done with a USB driveand a Buffalo NAS, found in one place! If anyone has any corrections oradd ons, please post it (I will revise this)! To the best of knowledge,I believe this is all correct...

 

Filesystem Limitations that you would need to think about:

 

FAT32

-You cannot create a file larger than (2^32)-1 bytes (this is one byte less than 4 GB) on a FAT32 partition.

- 255 Characters (up to 255 UTF-16 code points long)

 

NTFS

- 255 Characters (up to 255 UTF-16 code points long)

 

ext3/XFS

- None

 

 ** I believe that these all have a directory limitation for a certain amount of subfolders, though I am not sure what that is.

 

What each Filesystem can do on a USB Drive connected to a Buffalo NAS:

 

NTFS        - Read over the network

 

FAT32     - Read over the network

              - Can be backed up to from the NAS

 

ext3/XFS- Read/WRITE over the network

              - Can be backed up to from the NAS

              

 

 

Backup Mode:

Normal Backup:

Saves as "yyyymmddhhmm\sourcename\data". Makes a new folder for each backup.

Overwrite Backup (Complete/Append)<labeledincorrectly as the first "Overwrite Backup (Complete/Differential)"

Saves as "_backups\sourcename\data". Does a complete backupevery time, if a file is on the destination that is not on the source,it will not be deleted.

 

Overwrite Backup (Complete/Differential):

Savesas "_backups\sourcename\data". Does a complete backup every time, if afile is on the destination that is not on the source, it will bedeleted.

 

Overwrite Backup (Append):

Savesas "_backups\sourcename\data". Does a complete backup the first time,subsequent backups only send the changes. If a file is on thedestination that is not on the source, it will not be deleted.

 

Overwrite Backup (Differential):

Savesas "_backups\sourcename\data". Does a complete backup the first time,subsequent backups only send the changes. If a file is on thedestination that is not on the source, it will be deleted.

 

*Summary: Complete backups do a complete back up every time (overwritingfiles). Append backups will not delete a file that has already beenbackup, if that file was deleted from the source,Differential backups will delete that file during the backup.

 

 

Other Notes:

 

-Windowscannot natively read ext3 or XFS formats, as it needs the help ofa third party software (like UFS Explorer), though they can easily bereadfrom the ever more powerful, not to mention free, Linux OS. Since allBuffalo NAS products run from a Linux kernel, they can all read thesefilesystems.

 

-Whenplugging and unplugging a USB drive from the NAS, you want to turn theNAS OFF first! This will prevent any "bad" disconnections that couldcause data loss.

 

-Buffalo only supports their NAS units to work with SINGLE Drive USB Drives, not units with two or more!

Message Edited by kevin on 07-23-2009 06:10 AM

[kevin]

As for UPS compatibilities...

Buffalo recommends using APC as well as Omuron

 

It depends on your LS model, the original LS Pro (LS-GL):

APC ES series home office style UPS, model # BE500, tested to work with theLinkstation Pro.

[howdoesthiswork]

   

Thanks Kevin, however not really the answer I was looking for.

 

You might like to add KB#000145 to the list which is the path limit I was referring to;

 

The Linkstation's USB drive has a file path limit of 120 characters. If the file is many directories deep, this limit can be reached quite quickly. This is a limit with EXT3 so it cannot be fixed in a firmware update. Users will need to implement shorter filenames or a shallower directory structure. This will appear on Terastations if the USB drive is formatted in EXT3 or possibly FAT32.

 

From the backup options listed there isn't an incremental option which answers my question.

What I was hoping for, would be a hybrid between the normal and a differential.  In that way, I could make a base image and then create incremental backups based on changed/deleted files which would have a yyyymmddhhmm\sourcename\data format. As I understand, I can have one base and a single latest copy of a differential or appended backup only.

 

There's no reposonse to the open file issue.  If a client has NAS files open while the backup is running, will it skip, retry or stop?

 

Thanks for the advice on UPS, however according to documentation on APC site, ES series with USB use powerchute to initiate a managed shutdown. How did you achieve this in your test?

 

I'm asking these questions because I'd like to know beforehand the likely outcome. Only then can I make an informed decision. I'm not here to beta test your hardware and second guess it's capabilities.

[kevin]

howdoesthiswork wrote:

The Linkstation's USB drive has a file path limit of 120 characters. If the file is many directories deep, this limit can be reached quite quickly. This is a limit with EXT3 so it cannot be fixed in a firmware update. Users will need to implement shorter filenames or a shallower directory structure. This will appear on Terastations if the USB drive is formatted in EXT3 or possibly FAT32.

I can see how 120 characters is easy to achieve, however if the NAME limitation for ext3/XFS is 255 characters then surely the limitation for the amount of directory characters should be way higher than that, considering the name IS in the directory! In fact, I believe that that specific limitation is not known (doesn't exist) with these two file systems.

 

I'll see if I can get this test to be sure, it may be best if you provide the model number of the unit... Also you should try formatting the drive to XFS and see if that has a different effect.

howdoesthiswork wrote:

There's no reposonse to the open file issue.  If a client has NAS files open while the backup is running, will it skip, retry or stop?

If the backup encounters an error, it will halt. Letting it ignore errors will only let it try the backup again the next time the schedule time is hit.

 

 

I personally have no hard documentation on the UPS, sorry... Maybe someone else has some more insight?

 

 

One more thing I forgot to add about the USB drives...

Buffalo NAS Units are only supported to work with Single Drive USB Drives!

Message Edited by kevin on 07-23-2009 10:41 PM