Hi,
I had many KVMs running in Ceph with very good performances but I decided to give a try to LXC on Ceph in order to benefit for near bare metal performances and lighter overhead on ressources but I was soon disappointed on the disk i/o side.
While in KVM (virtio-scsi + writeback cache mode) I got good performances when dealing with tons of small files, same was not true within LXC containers stored on Ceph.
Is it normal ?
Is it a bug ?
Is there something that can be tweaked somewhere ?
I suspect KVM handling its own block cache while LXC beeing more "near bare metal" only rely on the Ceph OS handling whith fewer cache.
Any idea ?
Best regards,
Walid Moghrabi
I had many KVMs running in Ceph with very good performances but I decided to give a try to LXC on Ceph in order to benefit for near bare metal performances and lighter overhead on ressources but I was soon disappointed on the disk i/o side.
While in KVM (virtio-scsi + writeback cache mode) I got good performances when dealing with tons of small files, same was not true within LXC containers stored on Ceph.
Is it normal ?
Is it a bug ?
Is there something that can be tweaked somewhere ?
I suspect KVM handling its own block cache while LXC beeing more "near bare metal" only rely on the Ceph OS handling whith fewer cache.
Any idea ?
Best regards,
Walid Moghrabi