Re: Unusual ZFS behaviour
- In reply to: Jonathan Chen : "Re: Unusual ZFS behaviour"
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Date: Wed, 27 Dec 2023 20:39:31 UTC
On 23/11/23 19:06, Jonathan Chen wrote: > On 22/11/23 19:49, Jonathan Chen wrote: >> Hi, >> >> I'm running a somewhat recent version of STABLE-13/amd64: >> stable/13-n256681-0b7939d725ba: Fri Nov 10 08:48:36 NZDT 2023, and I'm >> seeing some unusual behaviour with ZFS. >> >> To reproduce: >> 1. one big empty disk, GPT scheme, 1 freebsd-zfs partition. >> 2. create a zpool, eg: tank >> 3. create 2 sub-filesystems, eg: tank/one, tank/two >> 4. fill each sub-filesystem with large files until the pool is ~80% >> full. In my case I had 200 10Gb files in each. >> 5. in one session run 'md5 tank/one/*' >> 6. in another session run 'md5 tank/two/*' >> >> For most of my runs, one of the sessions against a sub-filesystem will >> be starved of I/O, while the other one is performant. > > I've run a few more tests, and the issue appears to be isolated to my > Alder Lake based system only. So it's more likely to be an issue with > the 'Alder Lake-S PCH SATA Controller [AHCI Mode]' or maybe the > scheduler using the P & E cores. I've updated to FreeBSD 14/STABLE, and I'm glad to report that this bug has gone away. I personally suspect that: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=274698 is the cause. Cheers. -- Jonathan Chen <jonc@chen.org.nz>