Working with Files Is Hard (2019) • Hacker News Board

Re: Working with Files Is Hard (2019)

#121

Post by smart_tech » Mon, Jan 27, 2025, 8:01 AM UTC

tliltocatl wrote: post #80

namibj wrote: post #47

Earlier quoted context omitted.

I wish someone would sell an SSD that was at most a firmware update away between regular NVMe drive and ZNS NVMe drive. The latter just doesn't leave much room for the firmware to be clever and just swallow data. Maybe also add a pSLC formatting mode for a namespace so one can be explicit about that capability... It just has to be a drive that's useable as a generic gaming SSD so people can just buy it and have casua…

Unfortunately manifacturers almost always prefer price gouging on features that "CuStOmErS aRe NoT GoInG tO nEeD". Is it even a ZNS device available for someone who isn't a hyperscale datacenter operator nowadays?

[dead]

Re: Working with Files Is Hard (2019)

#122

Post by etechbuy » Mon, Jan 27, 2025, 8:15 AM UTC

namibj wrote: post #104

tliltocatl wrote: post #80

Earlier quoted context omitted.

Unfortunately manifacturers almost always prefer price gouging on features that "CuStOmErS aRe NoT GoInG tO nEeD". Is it even a ZNS device available for someone who isn't a hyperscale datacenter operator nowadays?

Either you ask a manufacturer like WD, or you go to ebay AFAIK. That said, ZNS is actually something specifically about being able to extract more value out of the same hardware (as the firmware no longer causes write amplification behind your back), which in turns means that the value for such a ZNS-capable drive ought to be strictly higher than for the traditional-only version with the same hardware. And given that…

ZNS (Zoned Namespace) technology seems to offer significant benefits by reducing write amplification and improving hardware efficiency. It makes sense that manufacturers would push for ZNS adoption, as it can enhance performance without needing complex firmware. The potential for using lower-quality flash effectively is also intriguing. However, the market dynamics, like the value added by OEM stickers and the need for write-back capacitors, complicate things. Overall, ZNS appears to be a promising advancement for specific applications.

Re: Working with Files Is Hard (2019)

#123

Post by ein0p » Mon, Jan 27, 2025, 8:54 AM UTC

ryao wrote: post #119

ein0p wrote: post #118

Earlier quoted context omitted.

I mean that it's already "none" on the machine where I encountered this bug. "Upd" was merely to signal that I've made an edit to my post.

The mq-deadline part is what confused me. That is a competing option for the Linux IO elevator that runs under ZFS. Anyway, I understand now and thanks for the data point. I added a list of questions to GitHub that could help narrow things down if you take time to answer them. I will be watching the GitHub thread regularly, so I will see it if you post the answers after you return from your travels.

I was confused, actually, not you. The output was:

cat /sys/dev/block/8:176/queue/scheduler

[mq-deadline] none

However, this output does not mean what I thought it did - it means that mq-deadline is in use.

If I do

echo "none" | sudo tee /sys/dev/block/8:176/queue/scheduler

This changes to

cat /sys/dev/block/8:176/queue/scheduler

[none] mq-deadline