Re: Unusual ZFS behaviour
- Reply: Jonathan Chen : "Re: Unusual ZFS behaviour"
- In reply to: Jonathan Chen : "Unusual ZFS behaviour"
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Date: Thu, 23 Nov 2023 06:06:44 UTC
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. Cheers. -- Jonathan Chen <jonc@chen.org.nz>