On 05/09/2018 04:55 PM, Samuel Sieb wrote: > On 05/09/2018 04:37 PM, Rick Stevens wrote: >> On 05/09/2018 03:23 PM, Samuel Sieb wrote: >>> From just that line, it looks like >>> there is no data transferred at all. I've never understood what 100% of >>> I/O bandwidth means. How is the maximum calculated? Or does it mean >>> that out of all the data transferred, 100% came from this process? >> >> That's not what it means. The first percentage is how much of that >> task's execution time it spent being swapped in and out (0.00%). The >> second is how much of its execution time it spent waiting on I/O to >> complete (99.85% in this case). > > Right, so it's not actually transferring any data, it's just waiting on > I/O for some reason. Correct, and it's waiting because something is writing to the disk and blocking its ability to update the journal. Not completely blocking it as it spent 0.15% of its time doing something, uhm, "useful" during that sample. It's not even clear that there's an issue since I'd expect stuff like that to occur sporadically during times of heavy I/O. It's also common if you've just formatted an ext4 filesystem as it does, essentially, a "quick" format first, and slowly initializes the rest of the partition over some period of time. The idea is to make the filesystem usable quickly and get the housekeeping done in its spare time. Assuming this isn't a fresh "mke2fs -t ext4" on the partition, I'd still try to find what's beating on that partition before messing around with anything drastic like changing the journal commit timing. The jdb2 thing in iotop (if it happens a LOT) indicates there's something weird going on--but it is NOT the cause of the problem. Don't shoot the messenger! ---------------------------------------------------------------------- - Rick Stevens, Systems Engineer, AllDigital ricks@xxxxxxxxxxxxxx - - AIM/Skype: therps2 ICQ: 22643734 Yahoo: origrps2 - - - - You possess a mind not merely twisted, but actually sprained. - ---------------------------------------------------------------------- _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx
