4 ms·

Is there any special feature of tarsnap that I'm overlooking, or is it just another kid down the block?

bcl 17y ago
From the Design page (http://www.tarsnap.com/design.html http://www.tarsnap.com/design.html): The design of tarsnap was guided by the following four principles: Security: Backups should be secure against attackers ranging from "script kiddies" up to major world governments, even if they can compromise the systems on which the backups are being stored. Backups are supposed to be a tool for mitigating damage — not a potential vulnerability to worry about! Flexibility: Backups should be flexible and convenient. When you decide you want to create an archive, you should be able to store in it whatever files you want; if you decide that you want to delete an archive, you should be able to do it whenever you want, without impacting other archives; and there should be no arbitrary limits on how many archives you have stored, how often you can create new archives, or how long you can keep them for. Efficiency: Backups should be efficient, using a minimal amount of storage and bandwidth. If you archive the same file twice, it should still only be uploaded and stored once; likewise, if you move, rename, copy, or make small changes to a file (e.g., adding a small amount of new data to the end of a log file or mail spool) you should never need to re-upload the entire file. Utility: Backups should be provided as a utility, with linear (i.e., per-GB) pricing. Forcing people to figure out ahead of time how much data they want to back up so that they can sign up for the right "plan" is dumb, and having some customers subsidize other customers is inherently unfair.
- shmichael 17y ago
  This seems like more-or-less the standard feature set of other products. See, for example, products mentioned in the post: http://www.wuala.com/en/learn/features http://www.wuala.com/en/learn/features https://spideroak.com/engineering_matters#storage_savings https://spideroak.com/engineering_matters#storage_savings http://jungledisk.com/personal/desktop/features/ http://jungledisk.com/personal/desktop/features/ tarsnap offers a unique mix of these features, but so does any other product.
cperciva 17y ago
Tarsnap is unique in a few ways, but I don't know if you consider these important enough to be worth mentioning. For example: * Tarsnap was designed to be secure against even the most skilled attackers -- and was written by someone (myself) with non-trivial expertise in cryptography and computer security. * Because Tarsnap is built around tar(1), it is heavily scriptable; for experienced users this makes it far more flexible than any other tools. * Tarsnap is AFAIK the only backup system which works as a metered service -- pricing per byte of bandwidth and per byte-month of storage used, starting at a (very small) fraction of a cent per month. Where other services have fixed monthly fees, Tarsnap just looks at your usage and charges you accordingly. * I'm not sure if Tarsnap's snapshotting model is unique, but it's certainly unusual; and once Tarsnap users follow my advice of "forget everything you know about incremental backups", they all tell me that it's far more intuitive than other approaches.
- shmichael 17y ago
  Thanks for the clarification. I've added tarsnap to the post.
  - cperciva 17y ago
    Thanks! Just one small correction: Tarsnap isn't linux-only. It runs quite happily on BSD, Linux, OS X, Solaris, Cygwin... basically anything UNIXy.
    - shmichael 17y ago
      Corrected.

bcl 17y ago

From the Design page (http://www.tarsnap.com/design.html http://www.tarsnap.com/design.html): The design of tarsnap was guided by the following four principles: Security: Backups should be secure against attackers ranging from "script kiddies" up to major world governments, even if they can compromise the systems on which the backups are being stored. Backups are supposed to be a tool for mitigating damage — not a potential vulnerability to worry about! Flexibility: Backups should be flexible and convenient. When you decide you want to create an archive, you should be able to store in it whatever files you want; if you decide that you want to delete an archive, you should be able to do it whenever you want, without impacting other archives; and there should be no arbitrary limits on how many archives you have stored, how often you can create new archives, or how long you can keep them for. Efficiency: Backups should be efficient, using a minimal amount of storage and bandwidth. If you archive the same file twice, it should still only be uploaded and stored once; likewise, if you move, rename, copy, or make small changes to a file (e.g., adding a small amount of new data to the end of a log file or mail spool) you should never need to re-upload the entire file. Utility: Backups should be provided as a utility, with linear (i.e., per-GB) pricing. Forcing people to figure out ahead of time how much data they want to back up so that they can sign up for the right "plan" is dumb, and having some customers subsidize other customers is inherently unfair.

shmichael 17y ago
This seems like more-or-less the standard feature set of other products. See, for example, products mentioned in the post: http://www.wuala.com/en/learn/features http://www.wuala.com/en/learn/features https://spideroak.com/engineering_matters#storage_savings https://spideroak.com/engineering_matters#storage_savings http://jungledisk.com/personal/desktop/features/ http://jungledisk.com/personal/desktop/features/ tarsnap offers a unique mix of these features, but so does any other product.

cperciva 17y ago

Tarsnap is unique in a few ways, but I don't know if you consider these important enough to be worth mentioning. For example: * Tarsnap was designed to be secure against even the most skilled attackers -- and was written by someone (myself) with non-trivial expertise in cryptography and computer security. * Because Tarsnap is built around tar(1), it is heavily scriptable; for experienced users this makes it far more flexible than any other tools. * Tarsnap is AFAIK the only backup system which works as a metered service -- pricing per byte of bandwidth and per byte-month of storage used, starting at a (very small) fraction of a cent per month. Where other services have fixed monthly fees, Tarsnap just looks at your usage and charges you accordingly. * I'm not sure if Tarsnap's snapshotting model is unique, but it's certainly unusual; and once Tarsnap users follow my advice of "forget everything you know about incremental backups", they all tell me that it's far more intuitive than other approaches.

shmichael 17y ago
Thanks for the clarification. I've added tarsnap to the post.
- cperciva 17y ago
  Thanks! Just one small correction: Tarsnap isn't linux-only. It runs quite happily on BSD, Linux, OS X, Solaris, Cygwin... basically anything UNIXy.
  - shmichael 17y ago
    Corrected.