----- Mail original -----
> > Don't know. My hypotheses are :
>
> > * using plugin transactions compared to 1.2.10.x
>
> > * bdb version? but even with compat-db-47 and 1.2.10 the problem still
> > happens on CentOS7, though much less frequently. It never happens with
> > 1.2.10 with rpm bdb on CentOS5.
>
> > * change from mozilla ldap libraries to openldap libraries?
>
> > seems to be some sort of thread or transaction contention
that is reduced
> > when i add CPUs/increase checkpoint interval. It really looks like the
> > master server just does not send entries any more at some moment...
> > SSL/TLS
> > slows the things down so less entries are sent before everything gets
> > stuck...
>
> > I'll get back with more information (stacktraces)
tomorrrow.
>
> Another version :
> insufficient entropy generation speed for TLS/SSL total update
> (/dev/urandom
> vs blocking /dev/random), especially in VMs??
it is possible the VM system is running out of entropy, and apps to
experience long delays, to verify:
cat /proc/sys/kernel/random/entropy_avail
one way to fix this is to use and run the haveged service on the KVM
guest,
that can be downloaded from EPEL
it can also depends on the VM configuration, for example if using KVM
and
libvirt (recent version), use the KVM host entropy is with a configuration
similar to this:
<rng model='virtio'>
<backend model='random'>/dev/random</backend>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x09' function='0x0'/>
</rng>
</devices>
without that config, my test RHEL 7 KVM guest has quite a low entropy.
and the entropy will depends on the cpu characteristics.
Thank you Marc. I'll
try checking the entropy pool state during the total on-line import. We are using VMWare
for virtualization, so there is no simple way to expose host /dev/random to the guest
VMs... However i've had this problem (stucked initial replication) even with LDAP/389
replica protocol, though it happened much less frequently. Anyway, i've made a ticket
for this problem:
https://fedorahosted.org/389/ticket/47942