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While shipping tapes fits the original metaphor (station wagon full of mag tape was what we were told to never underestimate back in the 80s) a more practical e
by evgen 16y ago
While shipping tapes fits the original metaphor (station wagon full of mag tape was what we were told to never underestimate back in the 80s) a more practical example would be to use 2T hard disks. You would lose out a bit on information density, but the drives could be slammed straight into a storage array without the transfer step that tape requires.
A 2T disk is about 400cc of volume and 660g in weight. A 747-8 freighter has close to 690 m^3 of cargo space. Round that down to 680 and we could put 1.7 million disks into a 747-8 by volume. Unfortunately they would weigh more than one million kilos. By weight it could hold around 212,000 disk drives containing 424 PB. This gets you close to the same numbers that jgc came up with, but in a more useful format for attaching directly to a storage array.
- tomjen3 16y agoYou could do the same with SD cards, the card readers for that are very, very cheap and you could fit a lot more data into it.
- evgen 16y agoTrue, but I was trying to keep this in the realm of reality. A large org could actually shift this much data in a single day from step A (shutdown/pull drives) to Z (start using the new cluster on the other side of the world) using this method. Expecting someone to have a million or more SD card readers is not really a practical plan. I could have probably also increased the density by using blue-ray data disks, but having a similar number of optical drives waiting for disks was also not really practical. At one time this general process was how chunks of yahoomail migrated from our original Four11 colo on stanford campus to the yahoo colos in san jose and sunnyvale (except it was netapp drives and shelves packed into my miata instead of a 747 -- 1T of 18G drives with the top down doing 80-90 southbound on 101...fun times :)