Re: Analysing ceph performance with SSD journal, 10gbe NIC and 2 replicas -Hammer release

Lionel Bouton <lionel-subscription@xxxxxxxxxxx> · Sat, 7 Jan 2017 13:31:10 +0100



    Hi,

      
      Le 07/01/2017 à 04:48, kevin parrikar a écrit :

    
      i really need some help here :(

        
        replaced all 7.2 rpm SAS disks with new Samsung 840 evo 512Gb
        SSD with no seperate journal Disk .Now both OSD nodes are with 2
        ssd disks  with a replica of 2 . 

        Total number of OSD process in the cluster is 4.with all
        SSD.
    
    
    These SSDs are not designed for the kind of usage you are putting
    them through. The Evo and even the Pro line from Samsung can't write
    both fast and securely (ie : you can write fast and lose data if you
    get a power outage or you can write slow and keep your data, Ceph
    always makes sure your data is recoverable before completing a write
    : it is slow with these SSDs).

    
    Christian already warned you about endurance and reliability, you
    just discovered the third problem : speed.

    
    Lionel

  
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