[ceph-users] What exactly is the kernel rbd on osd issue?

2014-06-12 Thread lists+ceph
I remember reading somewhere that the kernel ceph clients (rbd/fs) could not run on the same host as the OSD. I tried finding where I saw that, and could only come up with some irc chat logs. The issue stated there is that there can be some kind of deadlock. Is this true, and if so, would you

Re: [ceph-users] What exactly is the kernel rbd on osd issue?

2014-06-12 Thread David Zafman
This was commented on recently on ceph-users, but I’ll explain the scenario. If the single kernel needs to flush rbd blocks to reclaim memory and the OSD process needs memory to handle the flushes, you end up deadlocked. If you run the rbd client in a VM with dedicated memory allocation from