-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello everybody, I got a drbd cluster with tgtd managed by pacemaker as my iscsi target I then got three kvm host servers connected with open-iscsi to this target. All servers use an dual nic 1G LACP (mode 4 bonding) connection to a cisco switch. On the servers the iscsi disk is managed by lvm. I use the bellow for all the disks in the drbd cluster servers and on for all the disks on the kvm hosts (so also the iscsi disks). echo deadline > /sys/block/sdi/queue/scheduler echo 0 > /sys/block/sdi/queue/iosched/front_merges echo 150 > /sys/block/sdi/queue/iosched/read_expire echo 1500 > /sys/block/sdi/queue/iosched/write_expire My first problem is that if i run dd[1] on one of the KVM host, all the kvm guests on the other machines drop dead because they cant get any IO any more. My second problem is that if I run a heavy IO job[2] inside a KVM guest it can take all the IO and the KVM guest on an other KVM host can't get any IO any more [1] ionice -c 3 dd oflag=direct bs=4M if=/dev/lvm2-vol/kvm07-snapshot of=/dev/lvm3-vol/kvm07-disk [2] nice -n 19 ionice -c2 -n7 pvmove /dev/vdb /dev/vdc Now my guess is this is because, there is no IO scheduling between the KVM host, they do IO scheduling on there own server but just pass the load to open-iscsi and tgtd. However if multiple server are connected to tgtd it seems to be that one server can take it all and the other connections just have to wait.... (till a heavy dd job that takes hours runs out...) So how should I configure my cluster and tgtd so an heavy IO jobs just doesn’t get all the IO and the other request get handled as well? Is this an impossibility? Kind regards, Jelle de Jong -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iJwEAQECAAYFAlOB7KkACgkQ1WclBW9j5HnZ8gP/faFZk0CHaefPgMlXWHQ8N0YT 7Cv3XFUUTenVYbsAam5KuNMb48QzEMQnNhKeS3LeBELPUBAxMOAh/meXHVxLaDiK L3ZnhLuxdWOsDCp1hSaIDAekPqhvUdxjfOznqbOfxjLGjXNYdPai1ZZK0AVUog/z sdDzFWRmTLEPHrTR3HM= =zVop -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe stgt" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
