Changes between Version 39 and Version 40 of FAQ
- Timestamp:
- 2011-05-19T15:52:31Z (13 years ago)
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FAQ
v39 v40 9 9 A: You know how with RAID-5 you can lose any one drive and still recover? And there is also something called RAID-6 where you can lose any two drives and still recover. Erasure coding is the generalization of this pattern: you get to configure it for how many drives you could lose and still recover. Tahoe-LAFS is typically configured to upload each file to 10 different drives, where you can lose any 7 of them and still recover the entire file. This gives radically better reliability than comparable RAID setups, at a cost of only 3.3 times the storage space that a single copy takes. (This technique is also known as "forward error correction" and as an "information dispersal algorithm".) 10 10 11 '''[=#Q3 -disable-encryption Q3]: Is there a way to disable the encryption phase and just use the encoding on the actual content? Won't that save a lot of CPU cycles?'''11 '''[=#Q3_disable_encryption Q3]: Is there a way to disable the encryption phase and just use the encoding on the actual content? Won't that save a lot of CPU cycles?''' 12 12 13 13 A: There isn't currently a way to disable or skip the encryption phase, but if you watch the status page on your local tahoe-lafs node for uploads, you'll see that the encryption time is orders (yes, plural) of magnitude smaller than the upload time, so there isn't much performance to be gained by skipping the encryption. We prefer 'secure by default', so without a compelling reason to allow insecure operation, our plan is to leave encryption turned on all the time.
