Re: Performances issues with SSD volume ?

Thomas SIMON <tsimon@xxxxxxxxxxx> · Mon, 18 May 2015 15:35:55 +0200



    Hi matheus,

      thanks for reply.

      
      Kernel is slightly different ; with a 3.10.23-xxxx-std-ipv6-64
      kernel (OVH kernel) on HDD server, and  3.2.65-1+deb7u1 kernel on
      SSD server.

      I'm using debian wheezy on both servers.

      
      I didn't changed the 2 parameters you talk about.

      
      Thanks,
      Thomas
      Le 18/05/2015 15:13, Matheus de Oliveira a écrit :

    
          On Mon, May 18, 2015 at 10:05 AM,
            Thomas SIMON <tsimon@xxxxxxxxxxx>
            wrote:

            
              After the change, I had the following behavior, and I
              don't understand why : everything seems to work fine (load
              is ~6/7, when it was previously ~25/30 on the HDD server),
              so the SSD server is faster than the HDD one, and my apps
              run faster too, but after some time (can be 5 minutes or 2
              hours), the load average increases suddently (can reach
              150 !) and does not decrease, so postgres and my
              application are almost unusable. (even small requests are
              in statement timeout)
          
          
        Before we go mad, what is the
          OS/kernel/distro that you are using? Did it change from the
          previous one?

          
          If Linux, have you disabled transparent_huge_pages and
          zone_reclaim_mode (two known problematic Linux features)?

        
        Best regards,

        
        -- 

          Matheus de Oliveira

            Analista de Banco de Dados

            Dextra Sistemas - MPS.Br nível F!

            www.dextra.com.br/postgres