back in the NIX days, when we had 32GiB of memory mapped with 32 1-G PTEs, I wrote a trivial venti that ONLY used dram. That was easy. Because you can keep up a single machine with 32G up for an arbitrarily long time, I did not bother with a disk. This work was based on the fact that lsub had used very little of their 32G coraid server (something like 3G? I forget) over ten years: venti dedups by its nature and that's your friend.
So maybe a pure-ram venti, with a TiB or so of memory, could work? "disks are the work of the devil" -- jmk ron On Fri, Jan 2, 2026 at 1:02 PM Bakul Shah via 9fans <[email protected]> wrote: > > Might be an opportunity for optimizing mmap + virtual memory architecture for > database specific applications.... (should be worth at least a few papers for > the academic crowd). > > > On Jan 2, 2026, at 12:39 PM, [email protected] wrote: > > > > You may want to read this: https://db.cs.cmu.edu/mmap-cidr2022/ > > > > Quoth [email protected]: > >> Further trying to sanitize venti, I decided to change my mventi (no > >> isects) for mmap IO. > >> > >> At a first stage I mmap the whole venti i arena partition (current size > >> 80GB, filled to 44GB). On a 64bit processor this is not a big thing, and > >> replace the file operations (rwpart in part.c and readarena in arena.c) > >> by memmove. > >> > >> As it works on amd64 FreeBSD, I can now eliminate the block cache and its > >> complications (IO over block boundaries) from the source making the > >> remaining source much clearer. > >> > >> The price is, that I have to rely on demand paging of the OS. So it is > >> probably not easily portable to plan9 or 9front. > >> > >> Can any body give ime a hint, how to map a partition to a segment in > >> 9front? ------------------------------------------ 9fans: 9fans Permalink: https://9fans.topicbox.com/groups/9fans/Tf991997f4e7bb37e-M44817a56f8c46bcdac466b1b Delivery options: https://9fans.topicbox.com/groups/9fans/subscription
