Re: Squeezing Performance of CEPH

Massimiliano Cuttini <max@xxxxxxxxxxxxx> · Fri, 23 Jun 2017 15:34:35 +0200



    Hi Ashley,
    
      
      You could move your Journal to another SSD this would remove the
      double write. 
    If I move the journal to another SSD, I will loss an available OSD,
    so this is likely to say improve of x2 and then decrease of
    x½ ...

    this should not improve performance in any case on a full SSD disks
    system.

    
    Ideally
      you’d want one or two PCIe NVME in the servers for the Journal.

    
    This seems a really good Idea, but image that I have only 2 slots
    for PCIe and 12 SSD disks.

    I image that it's will not be possible place 12 Journal on 2 PCIe
    NVME without loss performance..... or yes?

    
      Or if you can hold off a bit then bluestore, which removes
        the double write, however is still handy to move some of the
        services to a seperate disk.
    
    I hear that bluestore will remove double writing on journal (still
    not investigated), but I guess Luminous will be fully tested not
    before the end of the year.

    About the today system really don't know if moving on a separate
    disks will have some impact considering that this is a full SSD
    disks system.

    
    Even adding 2 PCIe NVME.... why should not use them as a OSD instead
    of journal solo?

  
_______________________________________________
ceph-users mailing list
ceph-users@xxxxxxxxxxxxxx
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com