On 22/07/17 12:10, Dave Reynolds wrote:
# Summary
We've started seeing an unusual JVM error message in some fuseki
deployments:
java.lang.InternalError: a fault occurred in a recent unsafe memory
access operation in compiled Java code
I don't think this is a Jena issue so not raising a Jira, but if anyone
has seen this and has any workarounds or correlations that might help
track it down I'd be grateful for any hints.
[snip]
It has been running stably for over a year on AWS EC2 servers. Several
weeks ago we shifted to a newer EC2 instance type (i3.large) which has
faster (nvme) disks. It has been solid [2] for the last few weeks
answering a standard set of large queries daily.
[snip]
[2] There is an issue with nvme disks on Unbutu which leads to disk read
errors but there's a known work around we've applied and we run quite a
few of this server class at the moment without problems. In any case,
none of the errors associated with the disk driver issues appear in the
syslogs for these instances.
In case anyone has to debug something similar ... I believe this is an
issue with nvme disk drivers on ubuntu and nothing to do with Jena other
than that jena over a big dataset is a good way to exercise a disk :)
In particular I think it is:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1668129
I thought we had this patched already and thought the symptoms were
different this time around. However, it looks like a recent update
reverted the patch and enough disk hammering caused the error message
from that report to start appearing in the syslog.
Dave
