On Mon, Jan 11, 2021 at 12:57 PM Richard Shaw <hobbes1069@xxxxxxxxx> wrote: > > So from what I understand once a file is >0 that you can't set nodatacow. Correct. > I'm playing around with cryptocurrency and the current one downloads the whole blockchain and it's at 65GB and growing. I think the growing part is the problem. That and it's being stored on /home which is a spinning disk not an SSD like the system disk. > > I'm seeing a lot of IO wait in glances and the system is sluggish even though CPU and memory usage is relatively low. > > Ideas? It'd be useful to know if this is some kind of database, if it's one big file or many, if it's doing insertions (typical with database) or append. It might just be busy and will settle itself out once it's done downloading. And even maybe know what the program is. And I can ask folks on #btrfs. Btrfs does quite a lot of delayed allocation so you might see higher IO wait than you're used to, but as a side effect it turns random writes into sequential writes which write and read faster and have less fragmentation. So it's overall better. But the system being sluggish makes me wonder if something else is competing for IO with this task and what that process's write pattern is too. It could be lock contention, the easy way to alleviate that is give one of the tasks its own subvolume. I'm assuming this problem is all over by now but if you can reproduce it the first thing to look at is sysrq+t https://fedoraproject.org/wiki/QA/Sysrq that likely fills the dmesg buffer, but 'journalctl -k --no-hostname -o short-monotonic > dmesg.txt` will do it and then you can upload that file somewhere and I'll bug someone about it :P if no one on here knows how to read sysrq+t (i'm not great at it unless it's really obvious). Ideally have the sysrq+t ready to just hit enter. When the sluggishness happens, hit return. If that's all normal we might have to get into bcc-tools or something. -- Chris Murphy _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/users@xxxxxxxxxxxxxxxxxxxxxxx
