
What Amazon’s RRS Really Means - gthank
http://www.nasuni.com/news/nasuni-blog/what-amazons-rrs-really-means/
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mdasen
The author seems to consider potentially losing 1 out of every 10,000 objects
in a year unacceptable. It's true that it isn't the reliability that I would
want for critical files, but many things are non-critical. For example:
YouTube stores multiple copies of every file (the original, 360p, 480p,
potentially 720p and 1080p and potentially using multiple codecs). One copy is
"critical". The others are nice to have. On a site like that, you can make the
original and the 360p critical so that you're always able to serve the video
and you always have the original and then if you need to regenerate the 720p
version, you just do that and really people can wait an hour - especially
since it still _works_ , albeit at 360p.

Likewise, think about the thumbnails that Facebook stores of images. If one of
them disappears, it can be regenerated. There's no reason to store so many
copies.

Amazon's new service level shouldn't be used for data you want to keep
absolutely safe. It should be used for data that you can regenerate if it
disappears since it will save you money. If you have to re-transcode 1 out of
every 10,000 videos a year (0.01%) while saving 50% on storage costs, you're
in a good place.

~~~
jnoller
To us (Nasuni - I am an employee) losing objects in the cloud _is_
unacceptable, therefore, the blog post reenforces that. The Nasuni Filer (our
product) is a local-to-the-site, cloud-backed filesystem - and losing objects
in a filesystem is simply unacceptable.

Therefore, using RRS doesn't make sense for our current and potential
customers who expect that our filesystem, and the snapshots of that filesystem
reaching back in time, will not loose data. Sure - you save some money using
it, but what happens (as the post points out) when you loose a root entry for
your filesystem?

RRS is interesting in the way that buying a really cheap hard drive is - you
know you're paying for reduced reliability, and if that's an acceptable risk
for you, fine. However to us, right now, it's an unacceptable risk to our
customers.

So, we agree with you - Amazon's new service level shouldn't be used for data
you want to keep absolutely safe, and keeping data safe is our job as a
company and product.

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pedrocr
I still find even RRS pretty expensive to handle my backup needs. It probably
still has excessive redundancy and too fast IO. I run a family server to
backup media and documents. The data there is already a consolidated/versioned
backup of other locations put on a RAID5 array. With these two levels of
redundancy already in place all I want is a cheap per GB storage online I can
rsync to.

With only photographs/video/music collections of 4 people I've filled 1TB very
fast and will have to swap bigger drives in very shortly. To backup even 1TB
in RRS means 1200$ a year. With that money I can just buy a second server, put
it on an existing commercial DSL connection somewhere else and run a daily
rsync.

Anyone know of any solution like tarsnap/rsync.net that is an order of
magnitude cheaper? Most of the backup services require proprietary clients
that I hesitate to rely on, and I doubt their "unlimited storage" claims
aren't just like "unlimited bandwidth" claims.

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random42
99.99 Durability does not mean "1 out of 10000 objects WILL drop", it means
"you can _legally_ expect 9999 out of 10000 objects not to be dropped, dont
come back suing us, if 1 out of 10000 objects goes missing".

Its basically a legal clause for SLA, to protect Amazon from lawsuit
inundation.

~~~
tszming
99.999999999% durability is only their "Design Requirements", but it is not
part of the SLA: <http://aws.amazon.com/s3-sla/>

