Zone size = hardware erase block size?

Posted Jun 1, 2023 22:38 UTC (Thu) by DemiMarie (subscriber, #164188)
In reply to: Zone size = hardware erase block size? by adobriyan
Parent article: Zoned storage and filesystems

How much does this improve storage performance compared to writing to multiple zones at the same time? Is it worth the decrease in filesystem performance? Or are zoned storage devices primarily intended for workloads that bypass the filesystem and handle everything in userspace?

Zone size = hardware erase block size?

Posted Jun 2, 2023 11:25 UTC (Fri) by adobriyan (subscriber, #30858) [Link] (1 responses)

> Or are zoned storage devices primarily intended for workloads that bypass the filesystem and handle everything in userspace?

Any application which expects to overwrite data in-place or write data randomly in LBA space is immediately disqualified from using zoned devices and must become small database-like engine (hello, O_DIRECT!) which writes is very precise order (less headache with Zone Append).

So, all classic block/extent filesystems are out. In theory, journalling filesystem may accept zoned device for external journal.

Zone size = hardware erase block size?

Posted Jun 19, 2023 14:10 UTC (Mon) by DemiMarie (subscriber, #164188) [Link]

From my perspective, ZNS essentially moves the flash translation layer from the device to the host. Linux filesystems (other than zonefs) running on zoned storage expose a full POSIX API, and that includes random write support. The question is what zone size will yield optimal performance for workloads that are random-write from a userspace perspective.