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Linux Equivalents for Novell's "Filer"?
Josh Berkus asks: "One of my clients would love to convert their entire office to Linux. But one thing keeps them tied to a NetWare file server: a little utility called 'Filer' Filer allows the sysadmins to retrieve deleted and overwritten files, up to a week after the event. With 70 secretaries using that server, that ability is crucial. I've looked around the Internet, but cannot find anything quite equivalent in the Linux world, except maybe hourly backups and that's a pain. What the client really needs is a utility/mod for the filesystem or network layer that archives files instead of over-writing or deleting them. I had one kernel hacker offer to write me something like that, but my client does not want to be a test case. Note, that we have nothing against Netware, it's just that this client has historically not been able to get good Novell support. Anybody know anything that's already in production like this? Is Reiser working on this for ReiserFS?" This sounds deceptively easy. If this was a personal machine, this would be easy, but the showstopper is that this has to work as a share meaning that this "trashcan" like functionality needs to be implemented at the filesystem level. While I can understand the submittors desire to not be a test case, if there doesn't exist a ready-made solution to this particular problem, how difficult would it be to add this on to ext2/ext3, Reiserfs or some other suitable open source filesystem and test it for reliability?
Perhaps you could look at cvsfs? Don't know if it actually works, but meh..
http://sourceforge.net/projects/cvsfs/
stuff
Here's a project that supposedly does that. They use a daemon that physically deletes the files after a while. It's not as cute as in Novell, where erased files were physically overwritten only when the system really needed the space.
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Nave H. Weiss
I know i saw a library a while ago on freshmeat that supplies a new unlink() function. This version will move the file into a trashcan area rather than just delete it. it could be worth investigating. after a quick search, it's apparently called libtrash.
I don't really know the software, so i can't vouch for it, but it seems to be taking a sensible approach. of course, the whole idea breaks if you use the kernel nfsd, so be careful with that.
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I'm guessing this may be out of your budget range, but you should know about Network Appliance filers' snapshotting capability. The filers create online "backups" by saving the state information about a filesystem. You could have snapshots of the state of the filesystem every day for a week and several times a day. I think they support something like a dozen snapshots at a time.
.snapshot directory, choose the latest image that has your file intact, and copy it back to the live filesystem. It's perfect for those belly churning "Ooops" situations.
All this does take up space on the filer, but only the changed blocks have to be saved. As long as your churn is pretty low it's not that much extra space.
If you lose or munge a file, all you have to do is cd to a special
Snapshots are also used for backups, so that you are always backing up a totally static image of the filesystem. No files changing midway through.
Yeah, filers are spendy, but when it comes to fast, reliable, easy to administer file service I really believe they are the best.
Other than that, I think Veritas added a similar capability to VxFS, but I don't recall it being quite as elegant.
Sarah
The key post was this one which pointed me at using:-
Very scary. Had to boot into a rescue system off CD first, mount HDD RO, then get enough tools to be able to backup the HDD to a remote box. Unmount disk and then run reiserfsck. Pray for a bit. Got all the db files back (and because they where in a directory that was deleted, they had all the correct names as well (once I'd found the directory)).
There was some minor file-system corruption for files that had been written frequently, but this was taken care of by restoring the previous backup and checking everything else from the RPM db. So, all-in-all not an experience that you would want to do on a daily basis, but definately worth it to restore 2 months of lost work (why oh why don't people use backups?).
As far as kernel hooks for undeleting data, the mailing list link above contains several discussions about this, but the general feeling seems to be that it is possible but Linus doesn't want it (see here.
The only Good System is a Sound System
Filer is in fact a DOS based frontend utility for managing files on Novell Netware servers. Being a DOS utility, it is obvious that filer is as old as the hills but is still very useful. Filer's functionality has been included in the GUI tools that Novell has developed over the years and is included in the outstanding NWAdmin utility and the less appreciated Console 1 tool. Today, the utility Salvage is even included in the Netware Client and is accessed from a context sensitive menu on the client machine's desktop.
Salvage, the feature's proper name, is a tremendously powerful feature of Netware. Basically, when files are deleted from Netware volumes, they are not truely deleted. They are unlinked or renamed and become invisible to the clients but, the deleted files remain on the Netware volumes. When the Salvage utility is invoked, these files can be displayed, selected and instantly restored.
Deleted files remain on the volume until the volume runs "out of space", at which time the oldest deleted files are automatically purged as necessary to allow space for new files. It is important to note that the space consumed by deleted files is not reflected in any of the client utilities and does not count in disk quotas. This means that from the clients perspective the volume will show that there are 30 Gigs free despite of the fact that the volume is in fact full, due to deleted files.
Another interesting note is that deleted files retain their rights attributes. Files invisible to a certain user cannot be seen or restored by that user if they are deleted. Only users that had the appropriate rights before the file was deleted can manipulate these deleted files.
The deleted files can also be purged manually from individual directories or the entire volume. Purging can also be configured to purge the deleted files immediately which is the recommended configuration of temp directories.
This beloved feature of Netware has always been admired. The user community has always requested it in other OSes but, as yet, the only thing to even come close is an NT/2000 add-on called Network Undelete, from the folks at Executive Software, the same people that brought us Diskeeper. Unfortunately, it's still not quite the same.
Several posts have stated that this should be a simple thing to implement. I cannot speak to the ease or difficulty of implementing this feature. However, one does have to wonder how easy it would really be. Considering that Salavge is such an old feature on Netware, that there have been so many requests for it in other OSes and yet Netware is still the only OS to offer it, one must conclude that it is not really so easy to implement.
If you have found a developer that is willing to try to implement such a feature, I strongly encourage you to get them going, regarless of whether you want to be a test case or not. The community would love and appreciate this feature in Linux and any other OS.
Not to be a complete twit - but I woulden't replace the Novell server. If it's stable and does what you want then I'd just let it be. Put your enenrgies into adding value rather than replacing somthing that works with something else. Perhaps a Linux based firewall is needed? Or Linux based VPN so people can get into the office network from home?
Office types love VPN from home - though I'd sugjest OpenBSD for the job over Linux, both would work fine and make people *very* happy if done correctly.
Cheers and good luck.
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