Google| Subject | Re: Adobe's Low hanging .... ? |
| From | Sandman |
| Date | 2014-07-13 16:31 (2014-07-13 16:31) |
| Message-ID | <slrnls56d9.6ul.mr@irc.sandman.net> |
| Client | |
| Newsgroups | rec.photo.digital |
| Follows | nospam |
| Followups | nospam (1h & 8m) > Sandman |
In article <120720142325575132%nospam@nospam.invalid>, nospam wrote:
Well, sure it is. With one backup, your data will not be lost unless both the master data and the backup data is destroyed at the same exact time.nospamSandmannospamPeterN
what you've shown above is that it's vital to have backups.
And not rely on just one backup, such as the cloud.
One backup is enough, more is even better.
one backup is better than nothing but it is definitely not enough to be safe
And if those odds scare you, then you create a second backup, but there are still odds that all three fail exactly at the same time. In theory all your backups could fail at the exact same time, but in probability math, even having your master and backup fail at the same time is extremely unlikely.
Let's do some math! You have two hard drives, with an expected lifetime of a couple of years when run 24/7, let's say three years.
In those three years, you have 36 months, so the chance of one of the hard drives failing in any given month is 1/36 (0.027%), and the chance of both failing in the same month is 1 in 36 squared, or about 1/1,300 (0.0007%). And that's for both failing in the same *month*.
Now, for this to be a problem, they need to fail in pretty much the same day, but let's say it needs to happen in the same week. There are 52 weeks in a year and 156 weeks in three years, so for both drives to fail the same week the chance is 1 in 152 square, or about 0.000043% percent chance of that happening.
Which is why you create a new backup instantly, like I just said.Sandmannospam
If you backup to a cloud service and it dies, you instantly create a new backup somewhere else. You don't say "damn" and wait for your master data to also fail in some way.
if your only backup fails, you no longer have a backup. that's bad.
two backups is the minimum but more is always better, with at least one off-site.
also, the entire concept of the cloud being a backup is itself flawed. that's not really what it's for.Depends on what cloud service we're talking about. Some are specifically made for online backup of data, like Backblaze, Carbonite or Crashplan
-- Sandman[.net]
2014-07-10-
