from my testing it seems latency dependent, under optimal conditions these errors barely show up…
but that’s with the storagenode having access to 98% more resources than what it uses.
so 2% hdd utilization avg
2% internet bandwidth utilization and 2% server load, on 500mbit fiber, 16 threads dual cpu’s, and IOPS equal to 2-3 x a CMR HDD, from a dual or triple raidz1 arrays, with ssd caching… so on and so forth.
Overkill x Overkill then i get maybe 1 error or less in a day… sometimes all the way down to 1 a week.
basically flawless run on the storagenode…
doesn’t take much before it will start going up, it seems it’s mostly latency dependent, i use a write cache with sync always, meaning all data goes to the write cache and is then written in bursts which helps make the iops less random writes and more sequential.
something similar can be done by increasing your write buffer to from 128k to 512k
or by moving the database to an SSD drive… just keep in mind that even tho this improves performance, it also moves the storagenode on to two devices rather than one, of which either fails will spell trouble.
but it does help a lot it seems.
really the errors doesn’t matter much, they just look annoying… so long as your successrates are pretty good then i wouldn’t worry about it…
if you can it might be a good idea to set your ssd (which i assume is a cache for your SMR HDD)
to sync preferred / always or something like that… the basic idea being all writes are routed to the cache and then written in bigger chunks, making the writes sequential instead of random and thus greatly increasing the write speeds.
also helps against fragmentation, ofc if you successrates are like 95%+ then why bother… but long term it might really pay off…
i should setup a test for that… might be interesting to know… because it’s so much easier to run on the default writes, the sync = always methodology is pretty demanding and will require the SSD to soak everything + max at the amounts of iops it can handle.
but with a single HDD i doubt that’s an issue, but my old sata ssd sure wasn’t up for keeping up with my zfs arrays