Use 100% Flash setup avoid rotational disk for get some performance in HDD with windows. Windows is very sensitive to disk latency and interface with latency provides a bad sense for customer some times. You can check in your Graphana for ceph your avg read/write when in windows go up 50ms or more the performance is a painful Regards Manuel De: ceph-users <ceph-users-bounces@xxxxxxxxxxxxxx> En nombre de Gesiel Galvão Bernardes
Enviado el: miércoles, 21 de agosto de 2019 14:26
Para: ceph-users <ceph-users@xxxxxxxxxxxxxx>
Asunto: Applications slow in VMs running RBD disks Hi,
I`m use a Qemu/kvm(Opennebula) with Ceph/RBD for running VMs, and I having problems with slowness in aplications that many times not consuming very CPU or RAM. This problem affect mostly Windows. Appearly the problem is that normally the application load many short files (ex: DLLs) and these files take a long time to load, generating a slowness.
I using 8Tb disks, with 3x replica (I've tried with erasure and 2x too), and tried with SSD cache and without SSD cache and the problem persists. Using the same disks with NFS, the applications run fine.
I've already tried change RBD object size (from 4mb to 128k), use qemu writeback cache, configure virtio iscsi queues, use virtio (virtio-blk) driver, and and none of these brought effective improvement for this problem.
Anyone already had similar problem and / or have any idea how to solve this? Or have a idea that where I should look to resolve this?
Thanks Advance,
Gesiel |
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