Re: [ceph-users] CephFS overwrite/truncate performance hit

2019-02-19 Thread David Turner
If your client needs to be able to handle the writes like that on its own, RBDs might be the more appropriate use case. You lose the ability to have multiple clients accessing the data as easily as with CephFS, but you would gain the features you're looking for. On Tue, Feb 12, 2019 at 1:43 PM

Re: [ceph-users] CephFS overwrite/truncate performance hit

2019-02-12 Thread Gregory Farnum
On Tue, Feb 12, 2019 at 5:10 AM Hector Martin wrote: > On 12/02/2019 06:01, Gregory Farnum wrote: > > Right. Truncates and renames require sending messages to the MDS, and > > the MDS committing to RADOS (aka its disk) the change in status, before > > they can be completed. Creating new files

Re: [ceph-users] CephFS overwrite/truncate performance hit

2019-02-12 Thread Hector Martin
On 12/02/2019 06:01, Gregory Farnum wrote: Right. Truncates and renames require sending messages to the MDS, and the MDS committing to RADOS (aka its disk) the change in status, before they can be completed. Creating new files will generally use a preallocated inode so it's just a network

Re: [ceph-users] CephFS overwrite/truncate performance hit

2019-02-11 Thread Gregory Farnum
On Thu, Feb 7, 2019 at 3:31 AM Hector Martin wrote: > On 07/02/2019 19:47, Marc Roos wrote: > > > > Is this difference not related to chaching? And you filling up some > > cache/queue at some point? If you do a sync after each write, do you > > have still the same results? > > No, the slow

Re: [ceph-users] CephFS overwrite/truncate performance hit

2019-02-07 Thread Hector Martin
On 07/02/2019 19:47, Marc Roos wrote: Is this difference not related to chaching? And you filling up some cache/queue at some point? If you do a sync after each write, do you have still the same results? No, the slow operations are slow from the very beginning. It's not about filling a

Re: [ceph-users] CephFS overwrite/truncate performance hit

2019-02-07 Thread Marc Roos
Is this difference not related to chaching? And you filling up some cache/queue at some point? If you do a sync after each write, do you have still the same results? -Original Message- From: Hector Martin [mailto:hec...@marcansoft.com] Sent: 07 February 2019 06:51 To: