Too Perfect a Mirror

Carewolf writes "Jeff Mitchell writes on his blog about what almost became 'The Great KDE Disaster Of 2013.' It all started as simple update of the root git server and ended up with a corrupt git repository automatically mirrored to every mirror and deleting every copy of most KDE repositories. It ends by discussing what the problem is with git --mirror and how you can avoid similar problems in the future."

Comments

Re:Lean how your tool works?

[vurian]

"I would also like to point out that the incompetence and arrogance of the KDE team is quite visible once you investigate a bit of their history." Actually, if you would investigate the history of the KDE sysadmin team you would find out that this handful of volunteers are doing a job that many full-time, well-funded sysadmins cannot rival. And.. Anyone who talks about "the KDE team" as if it's a single, monolithic entity doesn't know what they're talking about.

Re:No backups?!

[Doc Hopper]

Unless there are legal reasons to keep 5-10 years of backups, or you are dealing in more then 3-5 TB of storage to be backed up, or taking things off-site daily via courier tape is just too expensive.

I like your summary of three important reasons for tape archive. I'll restate in different terms.
1. Mid-term to indefinite data retention.
2. Large quantities of data, where "large" is a value greater than a single hard drive can reasonably store.
3. Disaster recovery planning.

But there are more.

4. "Oops".

That's the category of this KDE git issue. Recovering from an "oops". People screw up. How do you recover? I'm a big fan of having multiple layers in that onion: online snapshots, near-line replicas, and off-line tape backups are a basic three-tiered framework for figuring out how to protect the data. I'm amazed as big as KDE is, they don't have storage/backup expertise helping them keep their data secure. Makes me think I may have found my next open-source niche to fill.

5. Reliability. Contrary to the "fragile, expensive" opinion above, tape failure rates are demonstrably lower than hard drive failure rates despite regular handling. Research left to the reader; hard drives fail at a rate about fifteen times higher than their rated MTBF, which was already considerably higher than tape. Data on tape is far more resilient than data on a hard drive.

6. Cost. If you have to store data long-term, consider tape. Administrative, electrical, power, cooling, and storage requirements are all cheaper.

That's what I can think of off the top of my head; I'm sure there are more reasons for tape to be a good choice. The reality for many people that want to store their data "in the cloud" also is this:

I back up your "cloud" storage onto tape drives. Your cloud storage is only as reliable as my ability to recover it from a disaster.