On Tue, Oct 31, 2017 at 12:36 AM, Lew Wolfgang
On 10/30/2017 01:30 PM, Greg Freemyer wrote:
Are you familiar with LTFS which LTO has supported since 2010 or so:
https://en.wikipedia.org/wiki/Linear_Tape_File_System#Nature
Thanks for the pointer, Greg. I don't recall hearing about LTFS
I've never used, but I know a world class tape expert. He is using it for data archiving, but not daily backups. If you have 10 thousand plus tapes you want to retire from your enterprise, watch this video: http://www.sullivanstrickler.com/invenire.html One thing he does is migrate the data from legacy tapes to new generation LTO. LTFS is part of his solution. I did some reading/questioning.
You use your library to make a full copy of the filesystem, then as files change, you write them to the tape via LTFS.
Unfortunately, that's all I know about LTFS. Questions you need to answer:
- Does openSUSE (or your OS of choice) have support
Looks like its available on SLES.
It also looks easy to compile youself.
- Does it provide point in time recovery. Or are you stuck with only the latest version of files.
I think you're stuck with the latest versions.
Agreed, but surprised.
- What happens when a file in primary storage is deleted?
The blocks are marked "unavailable" and the space not reclaimed.
Deletion indeed seems to make the file inaccessible. Strange to me for what I assumed was part of a backup solution.
I've been using rdiff-backup for years. It works well for on-line backups. It maintains a complete current image of the source filesystem, and calculates past point-restores as diffs. I run it on a daily basis and couldn't do without it now. I can restore with one day granularity going back for as many days as I've allowed. I usually trim it at 30-days. but it could archive for years. But I don't know how to use it with tape.
[I used to use rdiff-backup years ago. Replaced it with spideroak.] That seems to be the point of LTFS. It allows solutions like rdiff-backup to write to tape without modification. It presents a filesystem interface to rdiff-backup and translates that into tape commands on the backend. LTFS seems to work best with large files. rdiff-backup makes no effort to consolidate small files, but if your files being backed up, it should perform well. Next question: With a large dataset will a single LTFS filesystem span a tapeset? Are libraries supported?
Regards, Lew
I may have to buy an older generation LTO (5? 6?) and library myself if the tape library aspect works. I have 50 TB of large files I archive to a NAS. The NAS is awkward at times. Greg -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org