Hi, we have 2 servers on centos5.2 in a cluster with the redhat cman in the configuration SERVER1 > LVM \ CMAN DRBD > XEN SERVER2 > LVM / For each xen we create a new local LVM on each node, put them in a drbd and install an os (debian 4 or ubuntu 8). The xens are running as pvm. Everything works fine since over 4 months now. But we have some performance-Problems: Writing on the Xen-devices produces an iowait about 50 to 60% on the xen-processors. we have 3 szenarios tested: a) Xen on DRBD b) Xen on DRBD but disconnected c) direct mounted DRBD You can see the difference in Write pro Char and Write per Block. a: 3792 / 4011 b: 52037 / 103777 c: 57135 / 325002 See bonnie_result.txt for more data. We attached our drbd.conf and a xen-config for your information. The Server are each 2xDual-Core AMD Opteron(tm) Processor 2214 HE with 32 Gb RAM and 2TB-Harddrive on Raid5 running von CentOS 5.2. The XEN-DomUs are Debian 4 or Ubuntu 8. The NICs are bonded Intel 1GBit. For the DRBD we have an own connection on a seperately subnet. Though we are wondering what there happens. Any Idea? And: YES, we tried a some configurations in the last past months before we are asking you today :) Best regards an Thank you in advance Jan -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: drbd.conf.txt URL: <http://lists.centos.org/pipermail/centos-virt/attachments/20080818/db6fd1e2/attachment-0003.txt> -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: xen_config.txt URL: <http://lists.centos.org/pipermail/centos-virt/attachments/20080818/db6fd1e2/attachment-0004.txt> -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: bonnie_result.txt URL: <http://lists.centos.org/pipermail/centos-virt/attachments/20080818/db6fd1e2/attachment-0005.txt>