Re: Linux vs FreeBSD

On Apr 9, 2014, at 1:33 PM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> wrote:

> On Wed, Apr 9, 2014 at 9:02 AM, Christofer C. Bell
> <christofer(dot)c(dot)bell(at)gmail(dot)com> wrote:
>> On Thu, Apr 3, 2014 at 11:03 PM, François Beausoleil
>> <francois(at)teksol(dot)info> wrote:
>>> Hi all!
>>>
>>> Does PG perform that much better on FreeBSD? I have some performance issues on a Ubuntu 12.04 which I'd like to resolve. iowait varies a lot, between 5 and 50%. Does FreeBSD better schedule I/O, which could alleviate some of the issues, or not at all? I have no experience administering FreeBSD, but I'm willing to learn if I'll get some performance enhancements out of the switch.
>>>
>>> $ uname -a
>>> Linux munn.ca.seevibes.com 3.2.0-58-generic #88-Ubuntu SMP Tue Dec 3 17:37:58 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
>>
>> From the research I've done online, this is likely your issue. Kernel
>> 3.2.0 has some issues that directly and severely impact I/O wait times
>> for PostgreSQL. The suggested fixes (that seem to have worked for
>> most people reporting in) are to revert the OS to Ubuntu Server 10.04
>> or to install one of the HWE (HardWare Enablement) kernels into the
>> 12.04 system (this would be one of the kernels from a later release of
>> Ubuntu provided in the 12.04 repositories).
>
> 12.04 supports 3.8.0 directly. There's a site on putting 3.10.17 or so
> on it as well I found by googling for it. You need 3.10+ if you wanna
> play with bcache which is how I found it. But you don't need to jump
> through any hoops to get 3.8.0 on 12.04.4 LTS

Or wait <checks watch> 8 days for14.04 LTS with kernel 3.14.

Cheers,
Steve