5 ms·
> Could they not have gone with 64 bit addresses, was 18,446,744,073,709,551,615 addresses really not enough? Consider the counter-factual: what if 64 bits end
by throw0101a 5y ago
> Could they not have gone with 64 bit addresses, was 18,446,744,073,709,551,615 addresses really not enough?
Consider the counter-factual: what if 64 bits ended up being not enough?
Given all the effort that needed and still needs to be done to move from IPv4 to IPv6, if we eventually needed to move to IPv7/8 it would even more difficult given how much IP in general has/is pervading civilization.
It's better to have the extra addresses and not need them, than need them and not have them.
It's the reason why ZFS went with 128 bits as well:
> Some customers already have datasets on the order of a petabyte, or 2^50 bytes. Thus the 64-bit capacity limit of 2^64 bytes is only 14 doublings away. Moore's Law for storage predicts that capacity will continue to double every 9-12 months, which means we'll start to hit the 64-bit limit in about a decade. Storage systems tend to live for several decades, so it would be foolish to create a new one without anticipating the needs that will surely arise within its projected lifetime.
> If 64 bits isn't enough, the next logical step is 128 bits. That's enough to survive Moore's Law until I'm dead, and after that, it's not my problem. But it does raise the question: what are the theoretical limits to storage capacity?
* https://web.archive.org/web/20171118074243/https://blogs.oracle.com/bonwick/128-bit-storage:-are-you-high https://web.archive.org/web/20171118074243/https://blogs.ora...
- sliken 5y agoHeh, I'd argue that ZFS would be better if they went with 64 bits, especially since it's 2^128 blocks, not bytes, or bits. I did the math and it was something like a decade of the worlds production of disks, in a single filesystem. I could somewhat understand if it was a distributed filesystem, but it's not.
- kstrauser 5y agoAccording to back-of-the-napkin math, my home NAS has more storage than was manufactured globally in the year I bought my first computer. It doesn’t seem impossible that someone might have a single pool too big for 2^64 by the end of ZFS’s useful life.
- scoopertrooper 5y agoI did some calculations of my own. Assuming a index of size 2^64 and a block size of 256 KB, you could store 6,949,999,424,954 hours of 4k REDCODE36 RAW 4K video @ 120 fps before you ran into problems.
- kaashif 5y agoBut if proof of space cryptocurrency takes off, who knows how much of the world's disk production it'll use? ZFScoin to the moon! Just kidding, but maybe not.
- usr1106 5y agoThat's the way it has been in IT for 6 decades. The problem is it's not sustainable. We ruin the planet by inventing ever new ways of wasting resources for new solutions to problems that mankind doensn't even have.
- throw0101a 5y ago> I did the math So did Jeff Bonwick: > Thus, fully populating a 128-bit storage pool would, literally, require more energy than boiling the oceans. * https://web.archive.org/web/20171118074243/https://blogs.oracle.com/bonwick/128-bit-storage:-are-you-high https://web.archive.org/web/20171118074243/https://blogs.ora...
- saltharp 5y agoWhen was the last time you tried to memorize (or even type out) a ZFS block pointer address though? The ergonomics don't matter for ZFS, and so what's left to consider is address space exhaustion. For IPv6, people memorize/type IP address all the time. So the IPv6 designers needed to balance the address space size with ergonomics - and they did this poorly, imo.
- Dagger2 5y agoIf you need memorizable IPs, pick something like "2001:db8:2d4f:1::2", which isn't that much longer than the v4 equivalent of "203.0.113.45"+"192.168.1.2". In fact, it's five characters shorter. Increasing the address space by a factor of 2^96 while still reasonably allowing addresses shorter than the v4 equivalent seems like a pretty good balance to strike, especially when the vast majority of users use DNS or other automatic discovery and thus won't ever interact with them anyway.
- throw0101a 5y ago> For IPv6, people memorize/type IP address all the time. So the IPv6 designers needed to balance the address space size with ergonomics - and they did this poorly, imo. Most people have a hard time with remembering more than a handful of important telephone numbers (15 digits per E.164), so I don't think 64- (36:31:85:fc:bc:64:21:58) or even 48-bit (da:e1:4d:a5:9d:e7) addresses would be any easier. And if you don't like the current IPv6 addresses, be thankful the IETF didn't go with RFC 1561: > General purpose CLNP implementations MUST handle NSAP addresses of variable length up to 20 octets, as defined in ISO/IEC 8348 [11]. TUBA implementations, especially routers, MUST accommodate these as well. Thus, for compatibility and interoperability with OSI use of CLNP, the initial octet of the Destination Address is assumed to be an Authority and Format Indicator, as defined in ISO/IEC 8348. NSAP addresses may be between 8 and 20 octets long (inclusive). * https://datatracker.ietf.org/doc/html/rfc1561.html#section-4.9 https://datatracker.ietf.org/doc/html/rfc1561.html#section-4...