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Ext3 and RAID: silent data killers?

Ext3 and RAID: silent data killers?

Posted Sep 2, 2009 0:39 UTC (Wed) by drag (subscriber, #31333)
In reply to: Ext3 and RAID: silent data killers? by martinfick
Parent article: Ext3 and RAID: silent data killers?

> BACKUPS are poor, version control is the only sane backup.

If your using version control for backups then that is your backup. Your
sentence does not really make a whole lot of sense and is nonsensical.
There is no difference.

My favorite form of backup is to use Git to sync data on geographically
disparate machines. But this is only suitable for text data. If I have to
backup photographs then source code management systems are utter shit.

> Backups are horrible to recover from.

They are only horrible to recover with if the backup was done poorly. If
you (or anybody else) does a shitty job of setting them up then it's your
(or their's) fault they are difficult.

Backing up is a concept.

Anyways its much more horrible to recover data that has ceased to
exist.

> Backups provide no sane automatable mechanism for pruning older data
> (backups) that doesn't suffer from the same corruption/accidental deletion
> problem that originals have, but worse, amplified since they don't even
> have a good mechanism for sanity checking (usage)! Backups tend to backup
> corrupted data without complaining.

Your doing it wrong.

The best form of backup is to full backups to multiple places. Ideally they
should be in a different region. You don't go back and prune data or clean
them up. Thats WRONG. Incremental backups are only useful to reduce the
amount of dataloss between full backups. A full copy of _EVERYTHING_ is a
requirement. And you save it for as long as that data is valuable. Usually
5 years.

It depends on what your doing but a ideal setup would be like this:
* On-site backups every weekend. Full backups. Stored for a few months.
* Incremental backups twice a day, and resets at the weekend with the full
backup.
* Every month 2 full backups are stored for 2-3 years.
* Off-site backups 1 a month, stored for 5 years.
etc. etc.

That would probably be a good idea for most small/medium businesses.

If your relying on a server or a single datacenter to store your data
reliably then your a fool. I don't give a shit on how high quality your
server hardware is or file system or anything. A single fire, vandalism,
hardware failure, disaster, sabotage, or any number of things can utterly
destroy _everything_.


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Ext3 and RAID: silent data killers?

Posted Sep 3, 2009 7:51 UTC (Thu) by Cato (subscriber, #7643) [Link]

On full backups: one of the nice things about rsnapshot and similar rsync-based tools is that every backup is both a full backup and an incremental backup. Full in that previous backups can be deleted without any effect on this backup (thanks to hard links), and incremental in that the data transfer required is proportional to the specific data blocks that have changed (thanks to rsync).


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