Am 05.02.19 um 07:49 schrieb Chris Hartman: > Greetings! > > I actually messaged about this several months(?) ago, though you > articulated it better than I. > > I run a 2-node HA VM Cluster with KVM/pacemaker on top of DRBD 8.4 very > comparable to your hardware.and have experienced similar symptoms during > backup procedures. When it's really bad, one node will fence the other > because the remote disk becomes unresponsive past the DRBD timeout > threshold (auto calculated around 42 seconds). > > My only work around has been to keep all VMs on a single node at a time and > manually move all nodes periodically- this setup tolerates the I/O spike > much better. However, we don't get the performance benefit of having both > nodes active, not to mention the added administrative overhead.
Hi Chris, I found, that thotteling, limiting the I/O for virtual machine drives helps: I.E. # virsh blkdeviotune Virt-Name vda --total-iops-sec 1000 --total-bytes-sec 52428800 See also: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/virtualization_tuning_and_optimization_guide/sect-virtualization_tuning_optimization_guide-blockio-techniques But this is only a workaround, not the solution that drbd8 fails on heavy I/O, due self generated Load escalation. mit freundlichen Grüßen Jürgen Sauer -- Jürgen Sauer - automatiX GmbH, +49-4209-4699, [email protected] Geschäftsführer: Jürgen Sauer, Gerichtstand: Amtsgericht Walsrode • HRB 120986 Ust-Id: DE191468481 • St.Nr.: 36/211/08000 GPG Public Key zur Signaturprüfung: http://www.automatix.de/juergen_sauer_publickey.gpg
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