Hi Partick, Thanks for getting back to me. Looks like I found the issue. Its due to the fact that I had thought I had increased the max_file_size on ceph to 20TB turns out I missed a zero and set it to 1.89 TB.
I had originally tried to fallocate the space for the 8TB volume which kept erroring. I then tried DD and DD the entire space needed without errors. What I dont understand is, what happens to cephFS when you do this. The files I'm writing into the pre-allocated volume in ceph are still there "luckily" but I thought that ceph would stop you from writing to cephFS if it hit the upper limit of max_file_size. Kind regards, Kyle ________________________________ From: Patrick Donnelly <pdonn...@redhat.com> Sent: 11 May 2021 03:14 To: Kyle Dean <k.s-d...@outlook.com> Cc: ceph-users@ceph.io <ceph-users@ceph.io> Subject: Re: [ceph-users] Write Ops on CephFS Increasing exponentially Hi Kyle, On Thu, May 6, 2021 at 7:56 AM Kyle Dean <k.s-d...@outlook.com> wrote: > > Hi, hoping someone could help me get to the bottom of this particular issue > I'm having. > > I have ceph octopus installed using ceph-ansible. > > Currently, I have 3 MDS servers running, and one client connected to the > active MDS. I'm currently storing a very large encrypted container on the > CephFS file system, 8TB worth, and I'm writing data into it from the client > host. > > recently I have noticed a severe impact on performance, and the time take to > do processing on file within the container has increased from 1 minute to 11 > minutes. > > in the ceph dashboard, when I take a look at the performance tab on the file > system page, the Write Ops are increasing exponentially over time. > > At the end of April around the 22nd I had 49 write Ops on the performance > page for the MDS deamons. This is now at 266467 Write Ops and increasing. > > Also the client requests have gone from 14 to 67 to 117 and is now at 283 > > would someone be able to help me make sense of why the performance has > decreased and what is going on with the client requests and write operations. I suggest you look at the "perf dump" statistics from the MDS (via ceph tell or admin socket) over a period of time to get an idea what operations it's performing. It's probable your workload changed somehow and that is the cause. -- Patrick Donnelly, Ph.D. He / Him / His Principal Software Engineer Red Hat Sunnyvale, CA GPG: 19F28A586F808C2402351B93C3301A3E258DD79D _______________________________________________ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
