Re: Performances issues with SSD volume ?

Thomas

Hi Thomas,

This is just a wild guess. Are you using hardware RAID? Is the cache battery still working?

Cheers

On 18 May 2015 9:36 pm, "Thomas SIMON" <tsimon@neteven.com> wrote:

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@neteven.com> 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